The DARKROOM COOKBOOK, Third Edition

116 THE DARKROOM COOKBOOK
because in order to be fully effective, the print must be toned to completion, which means
lower dilutions (1:9 or less) resulting in an often undesirable color shift.
Gold-Toning for Protection
The classic formula for gold protective toning is Kodak GP-1 Gold Protective Solution. Like
selenium toner, GP-1 not only protects the print but causes a minimum color shift. What shift
there may be is toward a slight blue-black that some photographers fi nd pleasing. With some
papers, GP-1 will also improve separation in the highlights.
More recently it has been found that Kodak GP-2 offers more protection than GP-1.
Studies by the Image Permanence Institute (IPI) at the Rochester Institute of Technology
(RIT) indicate that it may be the thiocyanate present in GP-2, not the gold, which protects
the image. The IPI tests also brought into question whether gold toning was effective at protecting
photographic materials. Notably these tests were performed in 1988 and only on
microfi lm. More recent tests performed by Liam Lawless on Ilford Warmtone FB developed in
Dassonville D-3 indicate that the IPI tests may not be valid for paper and that the classic GP-2
formula does provide archival protection.
For further discussion on toning for archival quality, see Appendix 5: Archival Print
Procedure.
OTHER TONERS AND METHODS
Organic Dye Toners
Organic dye toners come in two types: mordant and straight. As carbon-based (organic) dyes
do not normally combine with inorganic compounds such as silver, mordant dye toners use a
speical bleach to convert metallic silver to either silver iodide or silver ferrocyanide so that an
organic dye will adhere to it. The dye is deposited in direct proportion to the density of the
mordant (bleached) image. In other words, the more silver that is mordanted the stronger the
fi nal color (Formulas: Toners: Two-Solution Dye Toner).
With straight dye toners, the silver is not converted and the dye affects all areas
equally. Although straight toning can produce vivid colors the lack of difference in toner
intensity between the highlight and shadow areas tend to create a fl at color effect. This can
either unify an image or make it visually dull. However, by masking off certain areas of the
image, selected areas can be toned using a straight dye toner, while others remain unaffected
(see Multiple Toning, below).
DuPont 6-T Toning System
The 6-T system consists of three separate bleaches, three separate toners, a sodium chloride
solution, plus a gold-tone modifi er. By mixing and matching the various bleaches and toners,
and throwing in the chloride bath and/or the modifi er, a large variety of tones can be
achieved from purplish-brown to a bright sunlit sepia. This system works best with old-style
soft emulsion papers. (Formulas: Toners: DuPont 6-T Toning System)