I'm new to lith printing and I have question regarding this technique. I've found that in the mid tone areas of the print I'm getting a discernable pattern or texture. It first happened with a neg from a pinhole camera and I thought I was seeing distortions from the pinhole. It's now happened with a lens neg.

I'm printing with a Durst L900 fitted with an Ilford Multigrade head. My theory is that I could be seeing the texture of the diffuser plate that's below the light mixing box. Is this likely and does anybody have suggestions for fixing this problem ?- short of getting rid of the enlarger. Thanks Jeremy

-- Jeremy Jeffs (doublex1@doublex.com), September 17, 2001

Answers

It's probably 'pepper fogging'. Rudman explains the phenomenon in his book pretty well. His solution was to add some sodium sulfite to the diluted developer. Good luck, DJ.

-- N Dhananjay (ndhanu@umich.edu), September 17, 2001.

No - I'm sure it's not pepper fogging - that's why I stressed this was a regular pattern and had a definite texture -thanks any way - anybody else have an idea?? J

-- Jeremy Jeffs (doublex1@doublex.com), September 18, 2001.

Hmmm, that's odd then. Do you see it only on lith prints or also in silver prints? I would try making some prints without any neg, at small apertures (so that DOF is at its maximum - most likely to reach the diffusor plate) on the highest contrat paper you can find. If you detect the pattern then, it probably is the texture from the diffusor plate. You could try replacing it with opal glass or something, I guess (you can get them from www.stephenshuart.com). Good luck, DJ

-- N Dhananjay (ndhanu@umich.edu), September 19, 2001.