I am having severe problems whilst attempting to print a series of pics as
continuous tone images on Process Supplies/Sterling Lith FB paper. With
Novalith, I am getting just the tonality & image colour I want, but am
bugged by "pebble fogging". This is a speckle-fog, across the midtones and
lower values. Highlights are free of it.
Kodak RT Lith does it a great deal less, if at all, but the image colour
is all wrong.
Novalith is a 2 pack liquid lith developer by Champion (UK). Like others
it is basically hydroquinone + sodium hydroxide. For lith, usual dilution
is 1A+1B+6H2O. To achieve continuous tones, I am using between 1+1+18 and
1+1+40. Dilution doesn't seem to affect the fogging. Nor does agitation,
temperature, safelighting or not. It is driving me nuts, not least when I
first tried this paper + dev a couple of years ago, I had no problems.
I have spoken to Process Supplies several times, and they say it is a very
common problem they haven't got to the bottom of - though some people
never get it, and others see it all the time. Some batches of paper seem
worse than others, but Sterling test every batch with Novalith, and seem
unable to replicate the problem. This makes me wonder if it's water
quality (here hard-ish, chlorinated/fluoridated London-style, 10 micron
filtered). God knows...
I imagine it is due to the infectious development getting a little out of
hand on the odd grain, but the distribution is so even that I suspect a
developer oxidation product or something, reaching such a concentration
that fogging occurs. PS mentioned a Sterling suspicion it might be due to
localised production of "an amino acid". Could be plankton for all I know.
I have tried reducing the proportion of sol B (the sodium hydroxide), but
contrast gets knocked back without much reduction in fogging.
I have tried all sorts of permutations of exposure/dev dil/temp/dev time,
with no effect on the pebble fogging
I have also tried dosing the dev with additional KBr, and that makes a
little better, but not a lot. Past a certain point, there's no improvement.
I have tried a different, very fresh batch of paper with no improvement.
It occurs to me to try additional sodium sulphite, maybe as well as KBr.
But PS said Sterling had been investigating and recommended reducing the
dev alkalinity by the addition of an unspecified amount of ascorbic acid
(vitC).
Whilst I am happy to give this a go, I have so far wasted a *lot* of paper
trying to get to the bottom of this, vitC is expensive here in UK in
retail quantities, and I am running out of time as well as money! Contones
on lith is such a seat-of-pants process at the best of times, and
variables seem to be multiplying in all directions... So I thought I would
ask here, just in case anyone has triumphed over this particular problem -
or has some damn clever idea what is going on and how to solve it?
Thanks if anyone can help.
Tony Sleep