The DARKROOM COOKBOOK, Third Edition

110 THE DARKROOM COOKBOOK
● Do not use an exhausted or over-concentrated stop bath. Stop bath left in the tray overnight
will evaporate and become concentrated. This can cause mottling in the base of a toned print.
Replace the stop bath frequently or use an indicator stop bath.
● Improper fi xing is probably the major cause of stains in toned prints. An exhausted fi xing bath
contains insoluble silver compounds that will be retained by prints and cannot be completely
removed by washing. When these residual silver compounds come into contact with a toner,
they form a yellow stain that is especially noticeable in the highlights and borders.
● Excessive fi xing with acid fi xers is almost as bad. Prolonged fi xing expands the paper and allows
the solution to penetrate the base. Acid fi xer that is trapped in this way is diffi cult to wash out
and may cause prints toned in selenium or sulfi de to turn yellow. Alkaline fi xers do not exhibit
this characteristic.
● Purple stains can occur in both selenium and sepia toner when prints have previously stuck
together in the fi xer.
● Avoid the use of hardening fi xers. Hardening fi xers do just what the name implies: They harden
the emulsion. This prevents toners from penetrating the emulsion and doing what they are supposed
to do. Use Plain Hypo, Looten’s Acid Hypo, Kodak F-24 Nonhardening Acid Fixer, TF-2, TF-3,
ATF-1 Nonhardening Rapid Fixer, or commercial formulas such as Photographers’ Formulary TF-4
Alkaline Fixer or Ilford Rapid Fixer.
● Insuffi cient agitation of prints, especially during the stop bath, can also cause mottling. The mottling
will not be evident until the print is toned with a selenium or sulfi de toner.
● Thorough washing before toning is especially important, unless otherwise indicated by the formula
or process. Residual silver salts and traces of hypo in the paper may cause stains, uneven
tones, and fading. Hypo Clearing Agent (HCA) may be used to conserve water without adverse
effect.
● HCA should be used after selenium toning and before washing. HCA is unnecessary after other
toners unless re-fi xing is indicated (for example, Nelson Gold Toner; partial redevelopment/
toning, etc.).
● While it is perfectly acceptable to tone prints that have just been fi xed and washed the most
consistent results are obtained from toning dry prints that have been re-wet for 5 minutes. This
is because the emulsion of freshly processed prints is still in a state of fl ux. This instability may
cause minor variations between prints, even within the same batch. If the prints are to be stored
for extended periods prior to toning, use proper storage techniques, as you would for any fi ne
print. Prints that have been stored in or around materials that off-gas may exhibit staining.
● It is diffi cult to wash toner from the edges of a print. Therefore, when toning RC paper, keep
toning times to a minimum to prevent the solution from penetrating the edges of the paper. If
toning times longer than fi ve minutes are anticipated with RC paper use salon borders of at least
one inch around the image. The same is true for fi ber-based prints meant to be toned for times
of ten minutes or longer.
● Toned prints should be dried face up on clean drying racks, as many toners will transfer to the
screen when placed face down. One exception is properly washed selenium toned prints, which
may be safely dried face down. Drying racks should be cleaned with a solution of household
bleach diluted 1:4 with water (wear gloves and use proper ventilation when using bleach).
● If you must dry toned prints with heat use the lowest and coolest setting. Heat drying may cause
a cool color shift in toned prints. You can often compensate by using a more dilute solution of
toner and/or toning the prints to a warmer color.
● Do not use metal trays or tanks. Use trays made of nonmetallic material such as glass, inert plastic,
or hard rubber.