pigmented colorants: dependence on media and time - Cornell ...

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Table 2.1: Average pigment particle size. Adapted from [Mac05]. Size Material Size Material 1000µm = 1 mm = 10 −3 m pyrroles 100µm coarse historical pigments naphthols 50µm smallest unmagnified 500nm wavelength of green light particles visible cadmium yellow cobalt violet titanium white manganese blue transparent red iron oxides 10µm cobalt green/turquoise translucent synth. organics cerulean blue arylides manganese violet benzimidazolones black iron oxides dioxazines 5µm viridian 100nm zinc white cobalt blue prussian blue violet/yellow iron oxides transparent synth. organics 1µm = 10 −6 m quinacridones ultramarine blue phthalocyanines red iron oxides 50nm carbon black cadmium red/orange 1nm = 10 −9 m opaque synthetic organics 0.3nm water molecule 23
A V = O(r2 ) O(r3 ) = 1 O(r) 24 (2.1) illustrates that the particle size is inversely related to the surface area. As particles decrease in size, the surface area increases. This affects the tinting strength of pigments, the colorant power in relation to its mass. As particles get smaller, the tinting strength is increased and the quantity of pigment needed to produce a required color intensity is reduced. Tinting strength also indicates how much a pigment will dominate the color of a mixture with other pigments. Tinting strength is an important characteristic when determining relative costs of different <strong>colorants</strong>. For example, an artist purchasing a tube of a particular colorant may wish to know which brand is the best value. If an expensive brand contains more pigment per unit volume, it has a higher tinting strength, and hence may be a better bargain. A larger surface area demands a higher ratio of liquid to pigment. There- fore, more finely divided pigments need more binder to maintain a similar paint consistency to that of larger particles. As the particle size goes below about 10 times the wavelength of light (particle diameter ¡ (4000-7000nm)), scattering effects begin to become significant. Incident light is reflected multiple times before exiting the medium. At this level, the increase in tinting strength is sometimes offset by the increase in total surface scattering. High scattering is desirable in white paints, because more scattering means increased hiding power and opacity; so fewer coats are necessary to cover the surface. Figure 2.10 illustrates how differently light behaves in response to varying particle size, given the same material. Finer ground pigments typically result in more
Page 1 and 2: PIGMENTED COLORANTS: DEPENDENCE ON
Page 3 and 4: ABSTRACT We present a physically ba
Page 5 and 6: Acknowledgements This work would no
Page 7 and 8: Table of Contents 1 Introduction 1
Page 9 and 10: List of Tables 2.1 Average pigment
Page 11 and 12: 3.15 Photoreceptor absorption .....
Page 13 and 14: B.15 Variation of spectral reflecta
Page 15 and 16: corrode the surfaces of materials.
Page 17 and 18: Figure 1.1: Detail of the Azor-Sado
Page 19 and 20: However, since mural artwork is typ
Page 21 and 22: at a very high quality (albeit limi
Page 23 and 24: heterogeneous sum of very different
Page 25 and 26: which linseed oil derives (the most
Page 27 and 28: oration of a rigidly painted layer
Page 29 and 30: ing will hit the ground and reflect
Page 31 and 32: tion of paint tubes in 1841 and the
Page 33 and 34: Figure 2.8: Natural pigments of ant
Page 35: ecome more common recently. The Ame
Page 39 and 40: Table 2.2: Pigment specific gravity
Page 41 and 42: provide the underlying color to a p
Page 43 and 44: though the speed of light in air is
Page 45 and 46: In general, when light travels from
Page 47 and 48: materials while lit from behind. Li
Page 49 and 50: Table 2.4: Index of refraction η f
Page 51 and 52: to completely congeal. Hence, these
Page 53 and 54: ond together to form proteins. Exam
Page 55 and 56: to its original state by any means.
Page 57 and 58: While it has been used since the 19
Page 59 and 60: organic binder found in more conven
Page 61 and 62: 3.1.1 Visible Light Spectrum Light
Page 63 and 64: Figure 3.2: Hue, brightness and sat
Page 65 and 66: measures how much light is reflecte
Page 67 and 68: Figure 3.6: Additive color mixing o
Page 69 and 70: Figure 3.9: The physical amount of
Page 71 and 72: The vascular tunic lies on the wall
Page 73 and 74: Figure 3.11: Cross section of the r
Page 75 and 76: Not all areas have the same sensiti
Page 77 and 78: identify and distinguish between va
Page 79 and 80: that range between zero and full in
Page 81 and 82: spectrum. This insures that the res
Page 83 and 84: Figure 3.19: Graphical representati
Page 85 and 86: X x = (X + Y + Z) Y y = (X + Y + Z)
Page 87 and 88:
color into the appropriate RGB colo
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components in the image (the smalle
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haviors of subtractive mixing and i
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of perceptually equal sizes. Unfort
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enabling one to transform between t
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andwidth as converted signals are s
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Figure 3.28: Retinal ganglion recep
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example shown in Figure 3.28. Under
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Figure 3.31: The work of Josef Albe
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sensations for each trial and picke
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Chapter 4 Previous Work There is no
Page 109 and 110:
different location. Subsurface scat
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describes the scattering and absorp
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only accounts for a small percentag
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σ ′ t = σa + σ ′ s and α
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104 Figure 4.4: A model of an alaba
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effects or are too computationally
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108 Figure 4.6: Results using Kubel
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specifying pigments works adequatel
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color representation, it is not fea
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time. A metallic surface patina is
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the system consisted of wetness and
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or darkening enables the museum per
Page 133 and 134:
in front of a displayed work. Felle
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light exposure. This effect is espe
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over time. Perceptually, these hues
Page 139 and 140:
The rate of change of the concentra
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over white grounds) suffer the grea
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protects the deeper remaining color
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light source. This method is used w
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chemical smog and have been identif
Page 149 and 150:
Chapter 5 Preparation & Measurement
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tending transparent pigments used i
Page 153 and 154:
140 Figure 5.1: Spectral reflectanc
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the requirements of the work at han
Page 157 and 158:
144 Figure 5.2: Left: Magnified vie
Page 159 and 160:
Table 5.2: Relevant data regarding
Page 161 and 162:
historically one of the best grades
Page 163 and 164:
created far too strong of a binder,
Page 165 and 166:
too brittle and cracking. While wor
Page 167 and 168:
154 Figure 5.4: Reflectance values
Page 169 and 170:
5.1.5 Painting After the layers of
Page 171 and 172:
The gray card reflected 18% of the
Page 173 and 174:
160 Figure 5.8: The optical setup f
Page 175 and 176:
Note that harmonics reflect at the
Page 177 and 178:
Note that the calibration factors f
Page 179 and 180:
Chapter 6 Experimental Results 6.1
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168 Figure 6.1: Lapis Lazuli in dif
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(such as CIE standards C, D50, orD6
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172 Table 6.2: Perceptual differenc
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174 Figure 6.3: Munsell plots of La
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and j has a saturation of red rsat,
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178 Figure 6.4: Variation of spectr
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visible spectrum are increasing at
Page 195 and 196:
182 Figure 6.5: Munsell plots of La
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trying to match color ca from the p
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as it ages. This is in direct contr
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teractive viewer. In our applicatio
Page 203 and 204:
190 Figure 7.1: Our simulated canva
Page 205 and 206:
where n is the normal at the curren
Page 207 and 208:
In summary, our implementation prov
Page 209 and 210:
Chapter 8 Conclusion We have studie
Page 211 and 212:
inks are beginning to find their wa
Page 213 and 214:
Appendix A Derivation of K-M theory
Page 215 and 216:
∆i − =(K + S) idx 202 ∆j −
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Equation A.8 is now: Rearranging yi
Page 219 and 220:
and if the paint is infinitely thic
Page 221 and 222:
One concatenates the layers into a
Page 223 and 224:
210 Figure B.1: Cold Glauconite in
Page 225 and 226:
Table B.1: Color conversions from t
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214 Figure B.4: Munsell plots of Co
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216 Figure B.5: Burnt Sienna in dif
Page 231 and 232:
Page 233 and 234:
220 Figure B.8: Munsell plots of La
Page 235 and 236:
222 Figure B.9: Red Ochre Tint in d
Page 237 and 238:
Page 239 and 240:
226 Figure B.12: Munsell plots of C
Page 241 and 242:
228 Figure B.13: Variation of spect
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230 Figure B.15: Variation of spect
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Table B.13: Color conversions of Bu
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234 Figure B.18: Munsell plots of C
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236 Figure B.20: Munsell plots of R
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References [Alb71] Josef Albers. In
Page 253 and 254:
240 [GLL + 04] Michael Goesele, Hen
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242 [KM31] Paul Kubelka and Franz M
Page 257 and 258:
[Rat72] Floyd Ratliff. Contour and
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