Fabrics for the twenty-first century - The Courtauld Institute of Art

Original research or treatment paper 

Fabrics for the twenty-first century: As artist 

canvas and for the structural reinforcement 

of easel paintings on canvas 

Christina Young, Suzanne Jardine 

Courtauld Institute of Art, London, UK 

The requirements for, and assessment of, suitable fabrics for artist canvas and for the structural reinforcement 

of easel paintings on canvas are presented. Crucially, the aesthetic and kinaesthetic, as well as physical 

properties of the canvas fabrics have been taken into account. To evaluate the fabrics the following 

properties were measured: stiffness, ultimate tensile strength, moisture response, crimp, drape, and lustre. 

Fabrics investigated include cotton, linen, polyester, polyamides, and carbonized fibres. Although 

polyester is yet to match linen or cotton kinaesthetically or aesthetically, overall it exhibits the best 

combination of properties. However, the results have shown that even when raw fibre material has suitable 

properties the finished woven fabric may not. This is because of the strong influence of the woven 

geometry on the final behaviour. It has been found that drape and lustre are very good properties to 

quantify some aspects of the feel and look of fabrics, in the context of conservation, and to provide a 

common language to ensure that the specification incorporates these aspects. 

Keywords: Canvas, Design, Lining, Mechanical, Aesthetic, Artist, Twenty-first century 

Introduction 

It has been 20 years since a wide range of fabrics 

(including polyester, nylon, and fibreglass) were 

tested to find options other than linen and cotton for 

the lining of paintings (Hedley, 1981). Following 

further research, it was suggested that woven polyester 

was the most promising fabric (Hedley, 1982). 

Subsequent smaller studies have investigated suitable 

synthetic fabrics; some of these have been adopted 

for short periods but have not found wide-scale acceptance 

(Ackroyd, 2002; Hapgood, 2007; Legris, 2009). 

Manufacturers and suppliers of artists’ materials 

have also looked, with some success, for solutions to 

mitigate the problem of the moisture response and 

degradation of natural fabrics (Labreuche, 2011). 

However, during the same period, sophisticated 

fabrics have been developed for the aerospace, military, 

and sports industries and, in the twenty-first 

century, advances in printing technology for graphic 

design applications have pushed the development in 

artist canvas. These developments, combined with 

the continuing trend for perceived minimally invasive 

methods and artists’ continuing exploration and 

Correspondence to: Christina Young, Courtauld Institute of Art, Somerset 

House, Strand, London WC2R ORN, UK. 

Email: christina.young@courtauld.ac.uk 

manipulation of canvas, suggest that it is timely to 

reassess what alternatives are available and what properties 

we require of such fabrics. This paper reports on 

one aspect of a two-year research project into the specification 

and assessment of fabrics in tension for 

architectural enclosures, artist canvas, and for the 

structural reinforcement of paintings on canvas. One 

object of the project was to design and/or identify a 

suite of fabrics, useful for conservators and artists, 

which met both the conservation requirements in 

terms of physical properties, and the required aesthetic 

and kinaesthetic properties, properties mainly lacking 

in the available synthetic alternatives to natural linen 

and cotton canvas. 

An important aspect of this work was to include, at 

the specification stage, the opinions and knowledge 

of conservators, internationally, who are regularly 

involved in the structural treatment of canvas paintings. 

Twelve such conservators answered the questionnaire 

(which allowed for three different scenarios and 

all aspects of the requirements of the fabrics). 

Discussions with a further ten such conservators, 

fabric suppliers and manufacturers, and ten years of 

experience of treating paintings and testing materials 

in the Conservation and Technology department at 

The Courtauld, formed the basis for the requirements 

© The International Institute for Conservation of Historic and Artistic Works 2012 

DOI 10.1179/2047058412Y.0000000007 Studies in Conservation 2012 VOL. 0 NO. 0 1

Young and Jardine Fabrics for the twenty-first century 

2 

and assessment criteria for the fabrics. Not surprisingly, 

a predominant requirement that arose was for a fabric 

that had the mechanical properties and minimal 

moisture response of the existing ‘restoration’ polyester 

sailcloth but the look and feel of linen. Replies to the 

questionnaire, and feedback at a canvas workshop 

held at The Courtauld, indicated that the fabric properties 

that were considered very important by more than 

50% of the conservators were: a linen lookalike, 

good handling properties, dimensional stability, and 

minimal response to moisture. The next most important 

criteria were the demands of the client for a ‘sympathetic 

look’ and the need for a stiff fabric to hold down 

cupping and tears. In all but three of the 36 treatments 

described by conservators, the adhesive used for strip 

lining or full lining was BEVA 371. An interest in a 

stiff but thin fabric for interleafs was also highlighted. 

Surprisingly, a fabric with minimal degradation was 

not felt to be a high priority but it was clear that preventive 

measures including deacidification, stretcher bar 

linings, and air filtering of pollutants were thought to 

mitigate some of the causes of degradation of linen 

and cotton. Essentially, the desired properties have 

changed little from those specified by Hedley (1981) 

over 30 years ago. 

The requirement for fabrics in conservation applications 

to have long-term stability and longevity, for 

instance, over 25 years (Ackroyd & Villers, 2003), is 

not normally applied by fabric manufacturers. They 

use the BS (British Standards), ISO (International 

Organization for Standardization), or ASTM 

(American Society for Testing and Materials) standards, 

which are performance tests based on industrial 

applications for fabrics requiring shorter service lives, 

hence these data are usually insufficient. Therefore, it 

is necessary to collaborate with the manufacturers to 

inform them of specific conservation requirements 

and for them to inform us of practical limitations in 

the manufacturing process. Heathcoat Fabrics (incorporating 

Haywoods Ltd) was the Courtauld industrial 

partner for this research. They are the manufacturers 

of the polyester sailcloth modified for use as a ‘restoration’ 

fabric, L00169. They agreed to produce fabric to 

our requirements using existing fabrics as a starting 

point. A polyester plain weave fabric was chosen 

from their product range because it had similar feel 

and weight as medium-weight linen. However, it was 

anisotropic and modification to the material did not 

improve its properties. No further prototypes could 

be manufactured within the timescale of the project. 

There are many parameters that can be altered in 

the manufacturing process. These include choosing 

between continuous or spun yarns, spin direction 

and degree of twist of the yarn, the yarn diameter 

and density in each direction, the tension in each direction 

while weaving, additional finishing processes, and 

Studies in Conservation 2012 VOL. 0 NO. 0 

surface modifications. It would appear from discussions 

with a number of manufacturers that altering 

these physical parameters to modify the physical properties 

of the fabric is, to some degree, an empirical 

process. This is partly because design software that 

uses modelling of the complex woven structure of 

fabric is still to be fully developed (Tan et al., 1997; 

Manjit, 2009). Thus, the specification, manufacture, 

and testing of a new fabric is a slow iterative process. 

This factor combined with the small volumes required 

for testing meant that modifying existing fabrics was 

more efficient than starting from scratch. Thus, the 

original objective of a design specification developed 

into a list of desirable requirements. 

Fabric selection 

A range of potential fabrics, including woven and 

non-woven, were surveyed. Twill weave confers 

greater dimensional stability than plain weave. 

However, no suitable synthetic twill fabrics were 

readily available for testing. Triaxial woven fabrics 

(the third set of yarns at 45°) were of interest because 

they provide greater stability and strength in the bias 

direction (Scardino & Ko, 1981). This is the direction 

where the design of the stretcher and keying-out causes 

greatest stress (Young, 1996a). However, triaxial 

weaving looms are rare and a manufacturer was not 

found who could weave a fabric of appropriate type 

or weight for this application. Such fabrics could 

offer great potential in the future. Non-woven fabrics 

were not evaluated experimentally as part of this 

research because a preliminary survey found that 

they do not have good drape and have a tendency 

to creep (Das et al., 2005). Additionally, the resin 

binders in bonded non-woven fabrics may not have 

the required long-term stability (Aslanzadeh & 

Haghighat, 1990; Dupuis et al., 1991). 

A survey was made of commercially available 

uncoated plain woven fabrics in all fibre types from 

9 to 15 oz in weight with relatively even weave count. 

Fifty were found that met these criteria. Using data 

sheets and handling swatches from different suppliers, 

25 were found empirically from our own experience to 

be of similar stiffness, thickness, and flexibility to existing 

conservation fabrics. These 25 underwent uniaxial 

testing to eliminate fabrics where the warp and weft 

stiffness were found to be uneven or where there was 

a very large bias extension. This narrowed the group 

down to a subset of 15 fabrics for full testing, which 

included traditional and synthetic fabrics regularly 

used at present, and the most promising new fabrics. 

This category included fabrics sourced by conservators 

which they felt had aesthetic and kinaesthetic potential, 

but for which there were insufficient data to evaluate 

(Buzzegoli, 2008). Commercially available primed and 

unprimed polyester fabric provided a good starting

point for an artist canvas. For comparison, two grades 

of Belgium linen were also included in the majority of 

the tests because they are both used as artist canvas and 

as lining fabrics. The raw material types fully tested 

were cotton, linen, polyester in polyethylene terephthalate 

form (PET), polyamide (DuPont TM Kevlar ® and 

Nylon 6,6), and carbonized polyamide. Details of the 

fabrics are given in Table 1. 

It should be noted that some fabrics were supplied 

without additional coatings that would normally be 

added to the commercial product such as fire retardants 

(see Appendix 1), nor were the linen and cotton duck 

wetted and stretched to ‘decrimp’ by the authors 

before testing. As is known empirically, and shown 

experimentally (for natural fabrics which absorb a 

greater amount of water than synthetic fabrics) this 

‘decrimping’ process can result in the warp and weft 

stiffness becoming more similar (Young, 1996b; 

Young & Hibberd, 1999). Water is absorbed into 

fibres through bounding of their polar functional 

groups in the amorphous regions of their polymer 

structures. In the crystalline regions water cannot 

easily penetrate because of the closely packed structure 

and cross-linking of the molecules (Tímár-Balázsy, 

1999). Synthetic fibres have a lower proportion of 

polar groups in their amorphous region compared to 

natural fibres, and their degree of crystallinity is often 

higher (Morton & Hearle, 1993; Tímár-Balázsy, 

1999). Therefore, wetting and stretching should not 

produce a permanent change for the synthetic materials 

tested. However, lubrication of the yarns in the woven 

fabric does affect their tension (Young, 1996a). 

Measured properties of the fabrics 

The properties chosen to be measured were stiffness, 

strength, moisture response, crimp, drape, and lustre. 

The mechanical and physical properties of the 

fabrics were measured for the bulk woven fabric 

rather than the yarns or fibres e.g. stiffness (uniaxial, 

biaxial, and Young’s modulus). The relative degree 

of degradation of the fabrics chosen has been 

assumed from the published literature (National 

Research Council, 1992). However, finishing processes 

may play a role either in protecting or hastening degradation. 

It was decided that measurement of the moisture 

response of the woven fabric under biaxial restraint 

was more pertinent to this application than using published 

equilibrium moisture content values for yarns. 

The degree of the crimp of the yarns is thought to 

have an influence on the bulk properties of fabrics at 

low load, and thus it was measured in the warp and 

weft directions. Continuous or spun yarns were identified 

(using optical microscopy at 20× magnification) 

in each direction because they affect the moisture 

response, feel, and appearance. To provide a quantitative 

measure of the feel and look of the fabrics two 


parameters were chosen that are used by the apparel 

industry; these are drape and lustre. 

Uniaxial testing 

Uniaxial tensile testing was performed on an Instron 

4301, with a sample width of 25 mm, gauge length 

of 80 mm, and speed of 5 mm/minutes at 55% RH 

(relative humidity) ± 5% RH and 21 ± 4°C. A 

minimum of three samples were tested in the warp, 

weft, and bias up to a tensile load of 500 N. The thickness 

of the samples was measured, using a micrometer 

with a friction thimble to exert a constant force on 

each material, in three places for each sample and averaged. 

Previous testing by the authors (using the same 

equipment and test method) had shown that new 

12 oz cotton duck, Ulster and Fine Belgium linen, 

polyester sailcloth and monofilament all had uniaxial 

ultimate tensile strengths (UTS) far above the tensile 

forces that are exerted on a painting (Young & 

Hibberd, 1999). Thus, UTS was measured only for 

the previously untested fabrics. However, the 

maximum load exerted in all the uniaxial tensile 

tests was found to be at least a factor of four 

above typical working loads (Young & Hibberd, 

1999, 2000). 

Biaxial tensile testing 

A biaxial tensile tester measures the load and extension 

in two directions, usually chosen to be the weft and 

warp of the fabric. The principles behind their design 

are discussed in detail elsewhere (Young & Hibberd, 

1999). The tester consisted of four translation stages, 

where extension of the fabric is achieved by displacement 

of the stages with a resolution of 2 μm, measured 

for each stage by a linear variable differential transformer 

(LVDT) with an accuracy of ±0.7 μm. The stages 

are coupled to interchangeable grips, allowing selection 

of a suitable grip type for a given sample. A 

1 kN load cell in each axis measures the in-plane load 

with an accuracy of ±0.05 N. The tester can be operated 

in load control or displacement control mode, 

with the sample in a horizontal orientation. In displacement 

control, the fabric is held at a constant position 

and the change in load monitored. This change can be 

passive (creep) and/or active (moisture/temperature 

induced). This latter method was used to monitor the 

wetting and RH response of the fabrics. 

The integrated environmental chamber operates 

from −30 to +60°C and, from 0 to 100% RH, via 

feedback proportional integral derivative control and 

in-house software. It consists of two RHs and temperature 

sensors, one inside and one outside the 

chamber, and a heater and three fans inside the 

chamber. The humidity is pumped into the chamber 

from an ultrasonic mister and moisture removed by a 

chiller and/or CO2 cooling system. The amount, and 

Studies in Conservation 2012 VOL. 0 NO. 0 3


4 

Table 1 Fabric details 

Stock 

(width/m) 

Yarn 

count 

weft/cm Finishing 

Yarn 

count 

warp/cm 

Fabric 

thickness 

(mm) 

Weight 

(oz/m 2 ) 

Fabric Fibre material Yarn type Supplier Manufacturer 

5.2 0.23 50 22 Washed, 2 

scoured, 

and heat set 

9.1 0.42 24 24 Loom state 1.5 1.5 

Heathcoat 

Fabrics Ltd 

Sailcloth 00169 Polyester Continuous Heathcoat 


Heathcoat 


Plastok 

9.1 oz Clipper Polyester Spun Heathcoat 


Plastok 


Monofilament 55/31* Polyester Continuous Associates Ltd Associates Ltd 1.8 0.05 95.2 95.2 Loom state 1.5 1.56 

P110 2004 Polyester Spun AP Fitzpatrick Lascaux Colours 7.6 0.42 10 10 Not known No longer 

& Restauro 

available 

P110 2008 Polyester Spun AP Fitzpatrick Lascaux Colours 7.6 0.42 10 10 Not known 3.14 

& Restauro 

Fredrix ® Polyflax 1008 Polyester Spun Tara Materials, Tara Materials, 16.75? 0.39–0.48 30 20 Loom state 1.5 3.2 

Inc. 

Inc. 

Fredrix ® Polyflax 1008 Acrylic Polyester Spun Tara Materials, Tara Materials, 

Primed 

Inc. 

Inc. 

Stern 16207 Polyester Continuous Stern & Stern Stern & Stern 11.3 0.48 25 15 Scoured 1.42 

Industries Industries Inc. 

Inc. 

Stern 16221 Polyester Continuous Stern & Stern Stern & Stern 2.9 0.13 50 50 Scoured 1.55 

Industries Industries Inc. 

Inc. 

Carbotex 03_82 CF Carbonized polymide Continuous Sefar Ltd Sefar Holdings 1.3 0.09 85 85 Scoured 1.08 

(Nylon) 

Inc. 

Carbotex 03_120 CF Carbonized polyamide Continuous Sefar Ltd Sefar Holdings 1.8 0.12 90 65 Scoured 1.58 

(Nylon) in warp 

Inc. 

Polyamide (Nylon) in weft 

Peektex 17-220/56 Polyetheretherketone Continuous Sefar Ltd Sefar Holdings 1.3 0.13 40 40 Scoured 1.24 

Inc. 

Kevlar ® Scenic Polyamide 

Spun Russell & Heathcoat 

3.7 0.19 Loom state 1.5 1 

(polyparaphenylene 

Chapple Fabrics Ltd 

terephthalamide) 

12 oz Cotton Duck Cotton Spun Russell & India (mill 

12 0.62 21 15 Loom state 1.5 3.05 

Chapple unknown) 

Fine Ulster Linen 3151 Flax Spun Ulster Weaving Ulster Weaving 0.37 0.37 18 18 Scoured No longer 

Company Company 

available 

Fine Belgium Linen Flax Spun Russell & Belgium (mill 9.3 0.41 18 18 Scoured 2.13 


Superfine Begium Linen Flax Spun Russell & Belgium (mill 7.2 Scoured 3.05 


*55/31 denotes 55 μm filament diameter and 31 denotes 31% open area (OA).

ate of moisture entering the chamber, is controlled by 

relay valves on the outlet. 

Biaxial samples were prepared in a cruciform shape 

with the testing region being 273 × 273 cm. The loaded 

sample was stabilized to 5 N (no drift for 20 minutes). 

Load extension tests were performed on the fabrics 

between 5 and 200 N, with an exception of the previously 

untested monofilament fabrics which were tensioned 

between 5 and 400 N to check for failure. 

Cyclic loading 

The mechanisms that lead to slackening of canvas over 

a long time result from stress relaxation and creep 

under tension and recovery. These originate from the 

original preparation of the canvas on the stretcher, 

subsequent cycles of keying out or re-stretching, and 

environmentally induced movement. This slackening 

is caused by a combination of movement of the 

woven structure after the weaving and finishing processes, 

slippage between multifilaments/staples, viscoelastic 

creep of the constituent molecules of the fibres, 

and chain scission of the molecules resulting from 

degradation (Morton & Hearle, 1993; Tímár-Balázsy 

& Eastop, 1998). Various methods have been used to 

measure stress relaxation and creep in canvas under 

uniaxial tension (Conti et al., 1972; Michalski & 

Daly Hartin, 1996). However, the effects of creep 

and stress relaxation are hard to separate. The tests 

reported here repeatedly load and unload under 

biaxial tension because this replicates the forces 

acting on a stretched canvas. They do not replicate 

long-term viscoelastic creep. Stress relaxation of the 

fabric is calculated from the cyclic load/extension 

data. Practically, these data will indicate whether a 

fabric will become significantly slack over time once 

tensioned, and whether it is necessary to wet and 

stretch the fabric several times before use. 

Each sample underwent biaxial tensile cyclic 

loading a minimum of three times (the typical 

number of times that a canvas might be wet and 

stretched in the preparation process); the majority 

were cycled ten times. Tests were performed at 55 ± 

5% RH and 21 ± 3°C. 

Measurement of environmental response 

Wetting 

The procedure to assess the moisture response and 

ability of the fabrics to subsequently recover was as 

follows: the cruciform of fabric was pre-tensioned to 

50 N in the warp and weft direction, and then repeatedly 

re-tensioned until this load was stable for 20 

minutes. The upper surface of the fabric was then 

wetted with water with a sponge thoroughly until it 

felt damp on the underneath, and subsequently left 

to dry out. The temperature was kept constant 

during the tests. The RH below the fabric and the 


tension induced were logged until no change in the 

load occurred. Natural fabrics have a tendency to 

take up moisture and attempt to shrink. However, 

because the fabric is under biaxial restraint it increases 

in tension. Synthetic fabrics have a tendency to lose 

tension but not always recover. 

Relative humidity response 

To give a better understanding of the rate and magnitude 

of fabric response to ambient RH, samples were 

monitored for step changes in RH. The samples were 

tensioned as before. The RH was then reduced to 

10% until no further change in tension occurred, 

then raised to 40% instantaneously. After which it 

was raised in 15% steps to 85% RH. The RH remained 

constant at each step for one hour, ensuring that the 

fabric came into equilibrium before the RH was 

changed (Carlyle et al., 2008). 

Measurement of crimp 

Crimp is the ‘waviness’ imparted to yarns by the 

weaving process. On the loom, each alternate warp 

yarn is raised to insert the filling yarn (weft) into the 

warp to form a shed. As the warp is raised, the 

filling yarn is inserted through the shed by a carrier 

device. This results in the warp curving around the 

weft. The crimp is also affected by the yarn diameter, 

yarn density, and the tension in the weft yarn while 

weaving. Finishing processes can also change the 

ratio of warp to weft crimp. To measure the crimp, 

the weft and warp yarns were carefully removed from 

the unstretched fabric. The yarns were digitally 

imaged under a microscope at 5× magnification. An 

image of a 1 mm graticule with a resolution of 

0.01 mm was also taken for calibration purposes 

(pixels per mm). The yarn images were processed 

using Adobe Photoshop CS2 to measure the wavelength 

(λ) and amplitude (A) of the yarns (see 

Fig. 1). The crimp, C, was calculated using equation 

(1) and the crimp ratio, Cr, equation (2) was calculated 

using Pierce’s model (Pierce, 1937). 

C ≡ πA 

� �2 λ 

Cr = Cweft 

Cwarp 

Figure 1 Magnified (5×) image of 9.1 oz Clipper warp yarn 

showing amplitude and wavelength. 

(1) 

(2) 



6 

More sophisticated theoretical models have been 

proposed to describe crimp in fibres and yarns, 

which take into account yarn diameter and the 

angles of the curved elements (Manjit, 2009). 

However, these models were not developed for this 

research because the measurement of A and λ, resulted 

in estimated errors of λ ± 0.002 mm and A ± 

0.004 mm, thus the limiting factor in the accuracy of 

determining the crimp. 

Measurement of drape 

The tactile properties of a fabric with which there is a 

sensory response is known within the textile industry as 

‘hand’ and encapsulates not only physical but also 

human perception, physiological, and social factors. 

However, there is no direct measurement of hand. 

Researchers have attempted to develop different 

methods to evaluate hand; these usually involve measuring 

many parameters and attempting to correlate them 

with human studies (Pan, 2007). Drape, colour, lustre, 

and texture are important factors that affect the 

aesthetics and kinaesthetics of fabrics. Drape is just 

one factor that will influence hand and has been 

chosen as the starting point in this research because it 

is usually assessed empirically by feeling a fabric and 

observing how it hangs under its own weight. 

Practically, it affects the canvas or painting handling 

properties when stretching, lining, and folding around 

a stretcher bar. 

The textile and clothing industry use drape to class 

and compare batches of fabric. It is described by 

BS5058:1973 (British Standards Institute, 1973) as 

‘the extent to which a fabric will deform when 

it is allowed to hang under its own weight’. 

Commercially, measurements are made using the 

Cusick drape meter (Cusick, 1965). A drape meter 

was constructed based on the 1968 Cusick design 

(Cusick, 1968) capable of capturing digital images 

from which to calculate the drape coefficient (DC), a 

number between a theoretical maximum of 1 (stiff) 

and 0 (floppy). Two concentric discs in the middle of 

the opaque box hold the annular ring of fabric, allowing 

it to drape into folds around the bottom supporting 

disc and held in place by the top disc. The 

instrument has a supporting disc of 18 cm diameter, 

using test samples of 30 cm diameter. A shadow of 

the draped fabric is cast down onto the image 

window from a point light source above the discs. 

The shadow is imaged by a digital camera, and the 

area of the shadow the footprint is calculated using 

Image J software. The DC is calculated using 

DC = 

Area under the draped sample − Area of support disk 

Area of the sample − Area of support disk 

(3) 


The correlation of drape analysis using image processing 

techniques with other fabric properties has 

been investigated in relation to the apparel industry 

(Robson & Long, 2000). 

Measurement of lustre 

Lustre is a term used to describe the way light is scattered 

from a fabric resulting from reflection, refraction, 

and diffraction at the yarns. A combination of 

macro-level gloss measurement and micro-level 

image analysis of yarns has been applied to determine 

which parameters influence lustre (Kim et al., 2004). 

In the apparel industry, lustre is measured in accordance 

with BS3424-28:1995 (British Standards 

Institute, 1995) to determine the specular gloss of the 

coated fabrics. A modified version of this was 

employed on the uncoated fabrics using a Sheen 

Instruments Tri-Microgloss 20-60-85 Meter (Model 

160) at 60°. Measurements were made in three places 

for each warp, weft, and bias direction. 

Results 

Crimp data 

Table 2 and Fig. 2 summarize the measured parameters 

A (amplitude) and λ (wavelength) from which crimp 

and crimp ratio Cr are calculated. A Cr = 1 means 

that the warp and weft have the same crimp in both 

directions. P110 2008 has a warp crimp of 0.073, weft 

crimp of 0.027, and Cr = 0.37. Polyflax 1008 has a 

warp crimp of 0.09, weft crimp of 0.06, and C r = 

0.67. Therefore, the Polyflax 1008 has more even 

crimp, as does Ulster linen 3151 (Cr = 0.9), 9.1 oz 

Clipper (C r = 1.07), and Carbotex 03_82 (C r = 1.23). 

The Carbotex 03_82, 9.1 oz Clipper and the Stern 

16221 (Cr = 7.42) are the only cases where the crimp 

is greater in the weft than the warp. 

Drape data 

Table 3 and Fig. 3 summarize the drape data for both 

the front and back face of the fabrics. Rigid cardboard 

that does not drape has been used for comparison 

(measured DC = 1). The results demonstrate that 

Sailcloth 00169 has very little drape (DC = 0.91 

front), whereas Kevlar® Scenic (DC = 0.68 front) is 

closest to Ulster linen 3151 (DC = 0.64 front). 

Figs. 4A and B show the drape images for Ulster 

linen 3151 and Sailcloth 00169. The linen drapes 

well whereas the sailcloth drapes less. Some fabrics 

exhibit a large difference in their DCs between the 

front and back faces, most notably Plastock 33/51 

which has values of 0.48 (front) and 0.82 (back), 

respectively. Thus, it will conform to a corner or 

edge better with the front face uppermost. (This is 

the face that would be on the uppermost when 

weaving. Usually, fabric is rolled with the back face 

on the inside.) There is a small difference for

Table 2 Measured crimp properties of the yarns 

Fabric 

Weft 

wavelength 

(mm) 

Amplitude 

(mm) Cweft 

Figure 2 Bar chart summary of calculated crimp of the warp 

and weft yarns. 

Warp 

wavelength 

(mm) 

Amplitude 

(mm) Cwarp Cratio 

Sailcloth 00169 0.410 0.003 0.001 0.929 0.084 0.081 0.01 

9.1 oz Clipper 0.935 0.075 0.063 1.110 0.086 0.059 1.07 

Monofilament 55/31* 0.196 0.001 0.000 0.199 0.022 0.121 0.00 

P110 2004 0.974 0.047 0.023 1.119 0.074 0.043 0.53 

P110 2008 1.148 0.060 0.027 1.228 0.106 0.073 0.37 

Fredrix ® Polyflax 1008 

Fredrix 

0.756 0.059 0.060 1.160 0.111 0.090 0.67 

® Polyflax 1008 

Acrylic Primed 0.756 0.059 0.060 1.160 0.111 0.090 0.67 

Stern 16207 0.797 0.038 0.022 1.384 0.111 0.063 0.35 

Stern 16221 0.518 0.040 0.059 0.494 0.014 0.008 7.42 

Carbotex 03_82 CF 0.268 0.022 0.066 0.270 0.020 0.054 1.23 

Carbotex 03_120 CF 0.382 0.028 0.053 0.382 0.038 0.098 0.54 

Peektex 17-220/56 0.602 0.023 0.014 0.581 0.029 0.025 0.59 

Kevlar ® Scenic 0.711 0.042 0.034 0.541 0.044 0.065 0.53 

12 oz Cotton Duck 0.945 0.037 0.015 1.342 0.151 0.125 0.12 

Fine Ulster Linen 3151 1.126 0.083 0.054 1.734 0.135 0.060 0.90 

Fine Belgium Linen Not 

Not 

Not 

Not 

Not 

Not Not 

measured 

Superfine Belgium Linen Not 

measured 

measured 

Not 

measured 

measured 

Not 

measured 

*55/31 denotes 55 μm filament diameter and 31 denotes 31% open area (OA). 

Table 3 Measured drape coefficient 

Fabric 

Drape coefficient 

front face 

Drape coefficient 

back face 

Cardboard 1.00 1.00 

Sailcloth 00169 0.91 0.90 

9.1 oz Clipper 0.78 0.74 

Monofilament 55/31* 0.48 0.82 

P110 2004 0.78 0.75 

P110 2008 0.68 0.74 

Fredrix ® Polyflax 1008 0.81 0.81 

Fredrix ® Polyflax 1008 Not measured Not measured 

Acrylic Primed 

Stern 16207 0.85 0.83 

Stern 16621 0.54 0.54 

Carbotex 03_82 CF 0.56 0.77 

Carbotex 03_120 CF 0.91 0.90 

Peektex 17_220_56 0.84 0.93 

Kevlar ® Scenic 0.68 0.75 

12 oz Cotton Duck 0.91 0.87 

Fine Ulster Linen 3151 0.64 0.70 

Fine Belgium Linen Not measured Not measured 

Superfine Belgium Linen Not measured Not measured 

*55/31 denotes 55 μm filament diameter and 31 denotes 31% 

open area (OA). 

measured 

Not 

measured 


measured 

Not 

measured 

measured 

Not 

measured 

measured 

Not 

measured 

Figure 3 Bar chart summary of the DC for the back and front 

face. 

Figure 4 (A) Drape shadow for Ulster Linen 3151 (front face). 

(B) Drape shadow for Sailcloth 00169 (front face). 

Sailcloth DC = 0.91 (front) and DC = 0.90 (back). 

For Ulster fine linen (considered by conservators in 

many cases to have a desirable feel) DC = 0.64 

(front) and DC = 0.70 (back). 

During the workshop and discussions, fabrics with a 

DC between 0.6 and 0.85 were thought to ‘feel’ right. 

This region includes Ulster linen 3151, P110 2004, 

Polyflax 1008, Kevlar ® Scenic, and both Carbotex. 

For those who specifically wanted a stiffer lining 



8 

Table 4 Measured lustre 

Fabric Gloss coeff. Weft Gloss coeff. warp Gloss coeff. bias 

Sailcloth 00169 3.3 3.9 2.6 

9.1 oz Clipper 2.7 2.7 2.7 

Monofilament 55/31* 2 2.2 2.3 

P110 2004 2.1 2.1 2.1 

P110 2008 Not measured Not measured Not measured 

Fredrix ® Polyflax 1008 2.4 2.5 2.4 


Not measured Not measured Not measured 


Stern 16207 2.3 2.7 2.3 

Stern 16221 3.3 2.8 2.5 

Carbotex 03_82 CF 0.3 0.3 0.3 

Carbotex 03_120 CF 1.7 1.1 1.2 

Peektex 17-220/56 1.6 1.6 1.6 

Kevlar ® Scenic Approx 0.85 were preferred. Researchers have 

found drape correlates very well with fabric mechanical 

properties including fabric shearing and bending, 

and the subjective assessments of apparel designers 

(Collier, 1991). Thus, it is reasonable to suggest that 

drape is a measureable quantity with which to describe 

one aspect of the ‘feel’ of canvas fabric and hence of 

help when specifying to manufacturers or suppliers, or 

choosing a fabric for a specific application. 

Lustre data 

The gloss measurements (lustre) for the warp, weft, 

and bias direction are summarized in Table 4 and 

Fig. 5. Ulster linen 3151 has gloss coefficients of 2.2 

(weft), 2.1 (warp), and 2.1 (bias). P110 2004, linen lookalike, 

has values of 2.1 in all directions. This similarity 

in gloss correlates with its popularity with 

conservators in terms of appearance. It is achieved 

through a mixture having spun rather than continuous 

filaments, and dyeing them in one direction. Sailcloth 

00169 has the highest gloss coefficients of 3.3 (weft), 

Figure 5 Bar chart summary of measured luster (gloss 

coefficient) in the warp, weft, and bias directions. 


3.9 (warp), and 2.6 (bias). A negative point often 

cited for this Sailcloth is its synthetic shiny look and 

feel. This is a result of the white yarns and because 

they are continuous, which results in higher specular 

to diffuse light scatter from their surface. The remaining 

white multifilament polyester fabrics have gloss 

coefficients in the range of 2.3–3.3. Polyflax 1008 has 

values of 2.4 (weft), 2.5 (warp), and 2.4 (bias). This 

fabric has spun yarns in both directions. The spun 

nature of the yarns also imparts a hairiness because 

the fibres in the yarn splay out from the main core. 

In the apparel industry this property is measured as 

‘hairiness’ by three different commercial methods; 

the Shirley hairiness meter, the Zeigle hairiness meter 

(G566), and the Uster Eveness Tester 3. It has been 

shown that results from each method cannot be 

directly compared, as factors including the speed of 

the test lead to different results (Wang, 1998). 

However, a relative scale of hairiness for the fabrics 

tested here would provide additional useful data for 

fabric specifications. Hairiness provides a better 

surface for adhesion but conversely allows greater 

dirt pick-up. For dark-coloured linen (spun yarns), 

this dirt pick-up is less noticeable than for the white 

spun polyester fabrics. Thus, dyeing of these yarns 

would be desirable. 

Uniaxial tensile data 

Table 5 summarizes the stiffness (gradient of the load 

extension curve) and Young’s modulus calculated at a 

load of 50 ± 10 N for the warp, weft, and bias direction. 

Because the majority of published data for 

fabrics is based on uniaxial tensile testing, the uniaxial 

results are included for the reader to make comparisons. 

For the majority of fabrics tested, the measured 

weft stiffness was greater than the warp stiffness. The 

bias direction was the least stiff for all fabrics. By

Table 5 Calculated uniaxial and biaxial tangent stiffness and Youngs modulus 

Weft youngs 

modulus 

(GPa) 

Warp youngs 

modulus 

(GPa) 

Biaxial 

stiffness 

ratio 

Biaxial 

weft 

stiffness 

Biaxial 

warp 

stiffness 

Uniaxial 

UTS (N) 

Bias 

Uniaxial 

UTS (N) 

Weft 

Ave 

uniaxial 

UTS (N) 

Warp 

Uniaxial bias 

stiffness 

(N/m) 

Uniaxial weft 

stiffness 

(N/m) 

Uniaxial warp 

stiffness 

(N/m) 

Fabric 

Sailcloth 00169 68 790 72 496 67 43 >500 >500 >500 113 200 118 340 0.96 0.557 0.585 

(Note) 

9.1 oz Clipper 16 941 55 334 10 127 >500 >500 >500 61 690 102 340 0.35 0.156 0.264 

Monofilament 55/31 † 

10573 12 448 4636 167 128 76 46 954 38 730 1.21 0.994 0.82 

P110 2004 20248 26 188 8871 >500 >500 >500 31 203 73 441 0.42 0.084 0.198 

P110 2008 Not measured Not measured Not measured 12 671 36 397 0.35 0.027 0.0786 

Fredrix ® Polyflax 1008 34 183 26 744 7976 >400 >400 >300 80 908 97 012 0.83 0.206 0.247 

Fredrix ® Polyflax 1008 Not measured Not measured Not measured Not measured Not measured Not measured Not measured Not measured 


Stern 16207 53 989 97 805 Not measured >450 >450 Not measured Not measured Not measured Not measured Not measured Not measured 

Stern 16221 10 978 33 022 Not measured >200 >200 Not measured 195 900 37 400 5.24 1.610 0.308 

Carbotex 03_82 CF 6768 6586 3657 128 132 84 18 173 36 514 0.50 0.220 0.44 

Carbotex 03_120 CF 8339 8152 4098 154 159 98 26 050 26 224 0.99 0.250 0.24 

Peektex 17-220/56 6136 6100 3469 147 137 76 32 790 51 070 0.64 0.277 0.431 

Kevlar ® Scenic Not measured Not measured Not measured 87 461 274 430 0.32 0.464 1.37 

12 oz Cotton Duck Not measured 400* 

56 089 225 680 0.25 0.086 0.3454 

Fine Ulster Linen Not measured 582** 

3151 

37 219 263 710 0.14 0.091 0.636 

Fine Belgium Linen 32 860 9000 Not measured 700 400 Not measured 

Superfine Belgium 56 995 5000 Not measured 332 372 Not measured 

Linen 


† 

55/31 denotes 55 μm filament diameter and 31 denotes 31% open area (OA). 

* published in Young, 1996a 

** published in Carr et al., 2003 



10 

comparing across the uniaxial and biaxial data one 

can see that firstly, uniaxial data give lower stiffness 

and modulii. Secondly, the direction of highest stiffness 

(weft or warp) was in some cases reversed. Both 

these features occur because under uniaxial tensile tensioning 

the yarns are not restrained in the non-tensioning 

direction. Thus, the interaction between the pulling 

out of the crimp (low load), then the subsequent 

stretching of yarns (higher load), and the friction at 

the cross-over points is different than when under 

biaxial tensile tensioning under load control. 

For contemporary paintings and new artist canvas 

it is reasonable to suggest that, when new, goodquality 

artist linen and cotton-duck canvas has 

adequate strength. Therefore, values of UTS for new 

fabrics can be compared against their values (see 

Table 1). The quality available to and from the 

supplier can vary across batches, as canvas for artists 

is a small market dependent on the commodities 

market for its source. Both the raw material and the 

weaving will influence properties. For degraded paintings 

on cotton and linen, UTS values can be compared 

with published data, by the authors and other 

researchers, on archival and artificially aged painting 

reconstructions (Hackney & Hedley, 1981; Carr et al., 

2003). UTS values for new Ulster linen 3151, 12 oz 

cotton duck, and Sailcloth 00169 are approximately 

550, 600, and 900 N, respectively (Young, 1996b; 

Carr et al., 2003). Carbotex 03_120 CF, Carbotex 

03_82 CF, Peektex 17-220/56, and monofilament 

55/31 have significantly smaller UTS values than sailcloth 

e.g. in the warp their values are 154, 128, 147, 

and 167 N, respectively. However, these materials 

are much thinner, e.g. the monofilament 33/51 is 

0.05 mm thick compared to 0.23 mm for the sailcloth. 

Biaxial tensile data 

The biaxial stiffness and the biaxial modulus are summarized 

in Table 5. The stiffness of the fabrics in the 

warp and weft was calculated from the tangent of 

the load extension curves at 50 ± 10 N on the second 

loading cycle of tensioning; this is representative of 

the typical load on a 300 mm 2 stretched canvas 

(Young & Hibberd, 1999). (For new canvas a tension 

of 120–200 N/m needs to be applied to become 

taut.) For a universal comparison of mechanical properties 

in the warp and weft, Young’s modulus was calculated 

from tangent of the stress–strain curve (for a 

stress 50 N m 2 ± 10 N) on the second loading cycle. 

(Stress is defined as the load divided by area under 

load.) For example, monofilament 55/31 has a lower 

weft biaxial stiffness of 38 730 N/m than Sailcloth 

00169 which is 118 340 N/m. However, as stated 

earlier the monofilament is much thinner. 

Biaxial stiffness is a more intuitive method for comparing 

the data (as is used in the apparel industry). 


Figure 6 Bar chart summary of the biaxial tangent stiffness 

in the warp and weft directions. 

This is reasonable as long as dimensions and exact 

product used in the testing are given and hence a 

valid comparison can be made. Fig. 6 compares the 

biaxial stiffness of the fabrics. In all but one case, the 

weft direction is stiffer than the warp. The fabrics 

with the most even stiffness (ratio of warp to weft stiffness) 

are monofilament 55/31 (1.21), Sailcloth 00169 

(0.96), Polyflax 1008 (0.83), and Carbotex 03_120 

(0.99). The fabrics with the most uneven stiffness 

were Ulster linen 3151 (0.14), 12 oz Cotton duck 

(0.25), Kevlar ® Scenic (0.32), and P110 2008 (0.35). 

The data in Table 2 show that in the weft direction, 

the calculated crimp is less. However, a quantitative 

comparison of both the uniaxial and biaxial stiffness 

with the calculated crimp in the warp and weft 

showed no correlation. This is not surprising for 

values calculated at a tension of 50 N (Hookean 

region). It is generally accepted that for fibres, yarns, 

or the bulk fabric, the crimp influences the degree of 

extension under tensile load, at low loads, below the 

Hookean region. Calculation of the low-load stiffness 

using the load extension data was attempted. However, 

inconsistencies in the calculated values were immediately 

apparent. This is because in the initial part of 

the tensile test there is a slack region before the 

tension is taken up by the sample. This slack region 

turns into a crimp removal region and then the 

Hookean region. It has been shown by photographic 

observations of the crimp removal for individual 

polyester fibres during a tensile test that these regions 

cannot be ascertained from the load extension plot 

alone because there is no clear transition from one 

region to the other (Buer-Kurz, 2000). 

Cyclic loading data 

The difference in extension between the tenth and 

first loading cycles at 5 N was taken as a measure of 

the creep of the fabric. The difference in extension 

between the loading and unloading on the first cycle 

at half the maximum loading tension was taken as a 

simplified expression of the hysteresis. A ratio of 

these properties in the warp and weft was also

Table 6 Calculated biaxial stress relaxation and hysteresis 

Fabric 

Creep (5 N) 

warp, warp 

(mm) 

Creep (5 N) 

weft, weft 

(mm) Creep ratio 

calculated. Table 6 summarizes the values of creep, 

hysteresis, and their ratios for the fabrics tested. 

Figs. 7A and B show the cyclic load extension 

plot for P110 2008 and Polyflax 1008. It can be 

Hysteresis 

(200 N) warp, 

warp (mm) 

Hysteresis 

(200 N) weft, 

weft (mm) 

Hysteresis 

ratio 

Sailcloth 00169 0.27 −0.01 −0.05 0.36 0.28 0.79 

9.1 oz Clipper 0.77 0.89 1.15 0.53 0.66 1.25 


−0.01 0.12 −12 0.25 0.05 0.2 

P110 2004 0.41 0.47 1.15 1.37 0.61 0.44 

P110 2008 1.87 0.38 0.20 2.12 0.79 0.37 

Fredrix ® Polyflax 1008 0.14 0.09 0.67 0.38 0.45 1.2 



Not measured Not measured Not measured Not measured Not measured Not measured 

Stern 16207 0.10 0.04 0.44 0.34 0.20 0.59 

Stern 16221 0.51 2.98 5.85 0.45 2.13 4.72 

Carbotex 03_82 CF 1.90 1.07 0.56 2.21 1.30 0.59 

Carbotex 03_120 CF 2.08 1.95 0.94 1.76 2.32 1.31 

Peektex 17-220/56 1.88 1.18 0.68 1.90 1.41 0.74 

Kevlar ® Scenic 0.41 0.08 0.19 1.11 0.05 0.04 

12 oz Cotton Duck 2.27 0.384 0.17 3.04 0.79 0.26 

Fine Ulster Linen 3151 Not measured* Not measured Not measured Not measured Not measured Not measured 

Fine Belgium Linen Not measured* Not measured Not measured Not measured Not measured Not measured 

Superfine Belgium 

Linen 

Not measured* Not measured Not measured Not measured Not measured Not measured 

Note: Samples were not tested to UTS. Values quoted are the maximum load reached during stiffness measurements, actual UTS will 

exceed this. 

* Data published for the same fabric types but different batches (British Standards Institute, 1973; Dupuis et al., 1991; National 

Research Council (U.S.) Committee on High-Performance Synthetic Fibers for Composites, 1992; Tan et al., 1997; Robson & Long, 

2000; Buzzegoli, 2008). 

† 55/31 denotes 55 μm filament diameter and 31 denotes 31% open area (OA). 

Figure 7 (A) Cyclic load versus extension for P110 2008. 

(B) Cyclic load versus extension for Polyflax 1008. 


seen that in both cases there is greater creep and 

hysteresis for the warp direction. However, values 

are higher for the P110 2008 (creep is 1.87 mm 

warp, 0.38 mm weft; hysteresis is 2.13 mm warp, 

0.79 mm weft) than the Polyflax (creep is 0.17 mm 

warp, 0.09 mm weft; hysteresis is 0.38 mm warp, 

0.45 mm weft). 

Greater creep is exhibited in the warp direction for 

all fabrics except for the Stern 16221 and the 9.1 oz 

Clipper. These two fabrics are also the only ones to 

have a greater crimp in the weft than the warp. 

The least creep and hysteresis was exhibited by 

the Sailcloth 00169, 9.1 oz Clipper, monofilament 

55/31, Polyflax 1008, Stern 16207, and Kevlar ® 

Scenic. These data have provided comparative performance 

data rather than clearly identifying or correlating 

the mechanisms. By comparing the crimp ratio 

with the hysteresis ratio (see Fig. 8) and creep ratio 

one can see a general trend that shows that the 

greater the difference in warp and weft crimp (Cr 

tends to zero), the greater the difference in hysteresis 

or creep. However, no direct correlation was found 

for this set of fabrics between the amount of crimp, 

and hysteresis or creep. Thus, crimp cannot be used 

as a criterion for evaluating the suitability of a fabric 

in this context. 

Full wetting response 

Table 7 summarizes the wetting response data, tabulating 

the maximum or minimum tension in each 

direction Twarpmax and Tweftmax, and the difference 



12 

Figure 8 (A) Graph comparing hysteresis ratio to crimp ratio 

for the tested fabrics. (B) Graph comparing stress relaxation 

ratio to crimp ratio for the tested fabrics. 

between the initial tension before wetting and the final 

tension after drying out, ΔTwarp and ΔTweft (see annotations 

in Fig. 9A). 

Two main types of responses are observed on 

wetting. For the Ulster linen 3151, 12 oz cotton 

duck, Kevlar ® Scenic and Peektex 17-220/56, an 

increase in tension occurs. Figs. 9A and B show the 

response curves for 12 oz cotton duck and Peektex 

17-220/56. The cotton duck exhibits a fast increase 

Table 7 Calculated wetting and relative humidity response 

Fabric 

Wetting response 

Tmax (N) warp 

(1 N/second) in tension from 50 N in the weft and 

warp, to 177.24 N in the weft and 192.1 N in the 

warp, respectively. Once the fabric has dried out 

the final tension is 22.3 N in the weft and 13.8 N in 

the warp. This response is consistent with previously 

published data for cotton and linen (Collins, 1939; 

Young, 1999). Peetex 17-220/56 (Fig. 9B) exhibits a 

very small change in load in the weft of 1.4 N which 

remains on drying out. Of all fabrics tested Peektex 

17-220/56 (which has a partially crystalline molecular 

structure) was the least responsive to moisture. Even 

though Kevlar ® has a highly crystalline molecular 

structure, RH has a significant effect on the rate of 

moisture absorption in the fibre. Its equilibrium moisture 

content is linear with RH. At 95% RH its moisture 

regain from a dry state is 6.2% (Kevlar ® Technical 

Guide, 2008). This is consistent with the response of 

the Kevlar ® Scenic fabric. Presumably the yarns are 

swelling with increased moisture, and thus the fabric 

responses in a similar way to linen and cotton, increasing 

in tension when restrained, but with less 

magnitude. 

All the polyester fabrics (with the exception of the 

P110 and Carbotex fabrics) showed an initial fast 

decrease in tension on wetting followed by a partial 

recovery in tension on drying. Figs. 10A and B show 

the response curves for the Carbotex 03_82 and 

Polyflax 1008. Carbotex 03_82 loses the most tension 

down to 2.7 and 1.7 N in the weft and warp, respectively. 

It has a permanent decrease in tension of 11.6 

and 16.9 N in the weft and warp. Polyflax 1008 

(Fig. 10B) loses tension down to 38.7 and 39.0 N, in 

the weft and warp, respectively, recovering with a permanent 

decrease of 2.2 and 4.3 N. Polyflax 1008 and 

T max (N) 

weft ΔTwarp (N) ΔTweft (N) 

RH response rate 

warp (N/%RH) 

Rate weft 

(N/%RH) 

Sailcloth 00169 33.1 37.4 −8.0 8.3 −0.24 −0.15 

9.1 oz Clipper 45.2 40.6 −1.8 −2.6 −0.21 −0.22 


41.6 43.6 −5.0 −4.6 −0.11 −0.12 

P110 2004 2.9 5.9 −47.0 −44.3 Non-linear Non-linear 

P110 2008 35.7 32.7 −17.1 −16.9 Non-linear Non-linear 

Fredrix ® Polyflax 1008 39.0 38.7 −4.3 −2.2 −0.16 −0.13 



36.0 33.1 −10.7 −13.9 −0.16 −0.11 

Stern 16207 38.8 37.2 −7.4 −1.2 −0.20 −0.20 

Stern 16221 48.2 39.5 −2.1 −10.4 −0.30 −0.31 

Carbotex 03_82 CF 1.7 2.7 −16.9 −11.6 Non-linear Non-linear 

Carbotex 03_120 CF 2.1 4.6 4.5 9.3 Non-linear Non-linear 

Peektex 17-220/56 50.2 51.2 0.0 1.4 −0.03 −0.01 

Kevlar ® Scenic 76.5 122.5 −31.7 −25.6 Non-linear Non-linear 

12 oz Cotton Duck 192.1 177.2 −36.9 −27.6 0.62 0.62 

Fine Ulster Linen 3151 135.0 150.0 −42.0 −34.0 * * 

Fine Belgium Linen Not measured Not measured Not measured Not measured Not measured Not measured 

Superfine Belgium 

Linen 

Not measured Not measured Not measured Not measured Not measured Not measured 

*See Tan et al., 1997. 

† 55/31 denotes 55 μm filament diameter and 31 denotes 31% open area (OA). 

Studies in Conservation 2012 VOL. 0 NO. 0

Figure 9 (A) Tension response curve on wetting for Peektex 

17-220/56. (B) Tension response curve on wetting for 12 oz 

cotton duck. 

Clipper exhibit the lowest permanent changes in 

tension of all the polyester fabrics. Interestingly, 

acrylic primed Polyflax 1008 showed a greater 

response and permanent change (ΔTwarp −13.9 N, 

ΔT weft −18.4 N) than unprimed Polyflax 1008 

(ΔT warp −12.4 N ΔT weft −12.8 N). This is probably a 


result of the moisture sensitivity of artist acrylic 

paints, which has been reported elsewhere (Hagan & 

Murray, 2005). 

Fig. 10C shows the response curve for Sailcloth 

00169. Compared to unprimed Polyflax 1008 

(Fig. 10B) it has a high value of ΔTwarp (−17.5 N). 

Figure 11 (A) Tension response curve for step changes in RH 

for P110 2004. (B) Tension response curve for step changes in 

RH for P110 2008. 

Figure 10 (A) Tension response curve on wetting for Carbotex 03_82. (B) Tension response curve on wetting for Polyflax 1008. 

(C) Tension response curve on wetting for Sailcloth 00169. 



14 

Figure 12 Bar chart summary of maximum change in tension 

on wetting. 

This batch of sailcloth was found to have a different 

response to previously tested batches; the permanent 

change in tension results in a decrease in the warp of 

8.0 N and an increase in the weft of 8.3 N, compared 

to previous data that found a permanent decrease in 

the weft and warp of 25 and 18 N, respectively 

(Young, 1999). Figs. 11A and B show the response 

curves for the two batches of P110 tested. Both show 

unusual behaviour for a 100% polyester material in 

that they do not recover tension after wetting and 

drying. P110 2004 (Fig. 11A) loses tension on 

wetting and subsequent drying down to a value of 

5.9 N weft and 2.9 N warp, whereas P110 2008 

(Fig. 11B) has values of 35.6 N weft and 34.0 N 

warp, respectively. P110 2008 also takes only 1.5 

hours compared to 5 hours for the P110 2004, 

because it has absorbed less moisture. This difference 

may be a result of differences in the residual size in 

the fabric, the amount of twist in the yarn, or 

additional finishing processes. The PET from which 

the filaments are made may have different degrees of 

polymerization and crystallinity. Fig. 12 summarizes 

the Tmax data (see Table 7) which clearly demonstrates 

the relative moisture response of the fabrics. 

RH response 

Fig. 13A shows the response curve of Polyflax 1008, 

showing the change in tension as function of time at 

different RH values. The step drop in load corresponds 

to the step increase in RH. Assuming a 

typical relationship between equilibrium moisture 

content as a function of RH (high gradient at 

10–40%, plateau around 40–75%, high gradient 

75–95%), then the slope of the initial region, from 10 

to 40% RH, measures how fast moisture was taken 

up by the fabric and it gives a maximum response 

rate for the fabric. The slope of the region from 40 

to 85% RH measures the response rate for the fabric 

due to slow changes in typical RH conditions. 

Because the moisture diffusion processes are nonlinear, 

by applying step changes one can also identify 

which RH values result in large changes in tension. 

Table 7 summarizes the data, tabulating the slope for 

the 10–40% RH and the 40–85% RH changes. The 

response to RH is complicated by fast creep in some 

of the fabrics during the tests. This creep is probably 

because the water lubricates the yarn cross-over 

Figure 13 (A) Tension response curve for step changes in RH for Polyflax 1008. (B) Tension response curve for step changes in 

RH for 12 oz cotton duck. (C) Tension response curve for step changes in RH for Peektex 17–220/56. (D) Tension response curve 

for step changes in RH for Carbotex 03_82. 

Studies in Conservation 2012 VOL. 0 NO. 0

points and allows yarn slippage (Young, 1996a) or the 

water molecules acts as a plasticizer to allow filaments 

to slip past each other. The effect has been observed 

most in the continuous yarn synthetic materials. 

Figs. 13B and C show the response curves for 12 oz 

cotton duck and Peektex 17-220/56. In the initial 

10–40% RH region the cotton duck increases in 

tension with a delay before the tension reaches equilibrium 

at 40%. The fabric tension then increases in 

steps with step changes in RH. Peektex 17-220/56 

has a fast, but small drop in tension as the RH 

increases, then remains almost constant, until 85% 

RH where a small increase in tension occurs in the 

weft direction. Fig. 13D shows the response curve 

for Carbotex 03_82. It is clear that a different mechanism 

is occurring with the introduction of moisture to 

the fabric. The yarns are made of polyamide (moisture 

regain at 20°C, 65% RH is ∼4% (Sefar Ltd., 2009)) 

with a carbonized outer shell (not responsive to moisture). 

It is suggested that the outer shell prevents moisture 

from reaching the polyamide and thus it only acts 

as a lubricant allowing yarn slippage. The change in 

tension is not fully recovered on drying. Except for 

Kevlar ® , which behaves like cotton duck and linen, 

all other synthetic materials show a similar trend in 

moisture response to Polyflax 1008 but with different 

magnitudes. 

An attempt was made to correlate the measured 

moisture response from the wetting and RH tests 

with simple weave properties for each type of fabric; 

including weft and warp crimp amplitude, crimp 

ratio, weave count, and weave count ratio. No significant 

pattern emerged from these comparisons, probably 

because yarn diameter and twist also varied 

between the fabrics. 

Discussion and conclusions 

For artist canvas and fabrics for structural reinforcement 

of easel paintings on canvas, in the early 

twenty-first century, polyester (PET form) still offers 

the best starting point as a raw material. However, 

the exact geometry of the woven fabric plays a major 

role in determining its bulk properties. Thus, not all 

polyesters have the same response to moisture, nor 

the same balance of mechanical properties. Care also 

has to be taken in assuming the same properties 

from batch to batch for the same fabric, as variations 

in the manufacturing process occur that alter the fabric 

properties. 

The synthetic fabrics with the most even biaxial stiffness 

are monofilament 55/31 (1.21), Sailcloth 00169 

(1.04), Polyflax 1008 (1.20), and Carbotex 03_120. 

(1.01). The most uneven were Kevlar ® Scenic (3.14) 

and P110 2008 (2.87). The fabrics with the least response 

to moisture are: Polyflax 1008, Sailcloth 00169, loom 

state 9.1 oz Clipper, and Peektex 17-220/56. 


Drape and lustre were found to be useful parameters 

with which to quantify aesthetic and kinaesthetic 

properties of fabrics in the context of conservation. 

DCs between 0.6 and 0.85 give the ‘feel’ similar to traditional 

medium weight linen. A ‘stiff’ lining would 

require a DC greater than 0.85. Future research will 

relate the measurement of drape to flexural stiffness 

because this property directly measures out-of-plane 

properties of the fabric, and hence the ability to keep 

tears and cupping in-plane. 

Values of gloss in the range of 2.1–2.5 give an aesthetic 

similar to linen. This is achieved primarily by 

using spun rather than continuous yarns, and is 

further enhanced by dyeing the yarns in at least one 

direction. 

The amount of yarn twist will also have an influence 

(not evaluated as part of this study). Decreasing the 

yarn twist has been shown to decrease gloss (Kim 

et al., 2004). Twisting binds the fibres together and 

gives the yarn strength. There is an optimum twist 

factor for any yarn type depending on the fibre 

content and staple length. These two parameters 

could be incorporated into the design of future 

fabrics (Backer et al, 1956; Taylor, 2002). 

Overall, if aesthetics are not important and a very 

stiff fabric is required for lining with low moisture 

response and even properties, Sailcloth 00169 performs 

best. If a fabric is required which has very 

good kinaesthetic properties and quite good aesthetic 

properties, low moisture response, and is isotropic, 

then the Polyflax 1008 performs best. If a heavier 

weight fabric is required the loom state 9.01 Clipper 

is an option. These two fabrics also offer the best 

options for synthetic artist canvas. 

Clearly, application of an adhesive to the fabric will 

alter its properties when used as a lining canvas; this 

will depend on the type and penetration of the 

adhesive (Young & Ackroyd, 2001). An initial investigation 

into the application of adhesive and handling 

properties while lining was undertaken; further 

interpretation and application of these data, together 

with lining case studies, is reported elsewhere 

(Young, 2010). 

Both twill and triaxial weave geometries potentially 

offer better physical stability and resistance to tearing. 

Therefore, they will be investigated as part of future 

research. 

Surface modifications by irradiation with an 

excimer laser have been shown to affect the lustre, wetability, 

dyeability, and stability of the microstructures 

of the fibre surface (Lau et al., 1998). Surface treated 

polyester filaments have been developed for performance 

clothing which wick away moisture. Vapour 

deposition techniques have also been employed to 

modify the surface (Ma et al., 2005). Modification to 

the filament cross section e.g. trilobal cross sections 



16 

are another way to alter gloss. These are all potential 

methods to obtain the desired properties in the future. 

A dyed version and a heavier weight version of 

Polyflax 1008 would be of benefit. For artists who 

still prefer the aesthetic of natural fabrics, commercially 

available pH-buffered linen and cotton might 

address some of their disadvantages (Carey-Thomas, 

2005). Although there is still a big market for artist 

canvas (ColArt, 2009), in terms of the weaving industry 

the conservation market is insignificant. The emergent 

technology for surface modification of synthetic 

materials and continuing development of new 

materials means that almost certainly the requirement 

of conservation fabrics and artists’ materials could be 

met. However, the development of such fabrics is not 

considered commercially viable at present. 

Acknowledgements 

The projected was funded under an AHRC research 

grant, AH/E5018154/1, Designing for the 21st 

Century. Other acknowledgements include: Warwick 

University. 

All contributors to the questionnaire and attendees 

of the canvas workshop. 

Mike Entwistle and John Stimpson, Heathcoat 

Fabrics; Sefar Fabrics; Rick January, Tara Materials, 

USA; Kenji, Chelsea School of Art; Lynn Taylor, 

Royal College of Art; staff of the school of textiles, 

Galashields, Scotland; conservators from Tate, 

London; Metropolitan Museum and Museum of 

Modern Art, New York; and Opificio delle Pietre 

Dure, Florence. 

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Appendix 1: Summary of manufacturing 

processes 

Scouring: The cleaning process to remove the size from 

the fabric. 

Loom state: Fabric that is sold straight off the loom, 

with no washing/scouring and finishing processes. 

Finishing processes: Occurs after washing and scouring; 

they include fireproofing, rot proofing, and water 

proofing. 

Heat setting: A process to stabilize the yarns from 

shrinkage at elevated temperatures. The fabric is 

pinned out so it cannot shrink while heated to a temperature 

near its melting point. After this process the 

fabric will not shrink in temperatures up to the heat 

set point, whereas a fabric that has not been heat set 

would shrink (Entwistle, 2008). 

Calendaring: A finishing process where the fabric is 

passed the through heated rollers to make it shiny.

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