The development induction period is normally very rapid with lith film, and
if there are specks of dust, tiny bubbles (created when the developer flows
over the surface), emulsion areas that do not wet immediately, or any other
condition that prevents immediate wetting, you will get the pinholes. Why
the lith formulas do not include a wetting agent is a mystery to me; all
the formulas I created do have the agent, and pinholes are a rarity. As to
wetting agent, none of the proprietary liquids (including Tween) are
satisfactory for use in a developer. In my formulas I specify one of the
Polysorbate compounds (Polysorbate 3000, because it's a powder) but any
polymer from 1500 to 4000 is satisfactory - whatever you can get. Add one
gram of the Polysorbate to each liter of solution - and add it last after
all the other ingredients are totally dissolved, or even better, dissolve
the Polysorbate in water (it's very soluble, so as little as 50 ml is OK,
but I use 100 ml) and add that. It works.
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
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