Hey Mark,
What a good tip you gave, I will try it right away. I also use Slavish Unibrom and get uneven developments in strange spots (in the sky for instance). I am about to print 50x60 lith on this paper and was really concerned about the uneven development.
Now tell us about the Naccolith developer, does it work well with this paper?
I have tried for months to find it in Europe bat alas no success.
Vincent
Or you could try the aquarium pump approach (if you have one handy)!
I'll share with you 2 of the forum posts from Russia in The World of Lith Printing
Tim
Method of continuous developer stirring: Lith printing on cold-tone papers (Forte Bromofort, Polygrade and Slavich Unibrom) can be a challenge as they are very responsive to infectious development and tiny variations of semiquinone, so if an area comes in contact with high-semiquinone developer it rapidly darkens. Semiquinone rises when exhausted developer comes in contact with fresh developer. Due to agitation developer near the edges of tray is fresher and developer near the print is more exhausted. Thus prints will have darkened edges and some random streaking along developer flow. My solution was to develop emulsion in a thin moving layer of developer using an aquarium pump to continuously supply developer to the centre of print from the bottom of tray. Due to high productivity of pump (around 10 litres per minute) and water surface tension, developer forms thin even layer on the surface of print. Developer in this layer is quickly exchanged; fresh portions come to the centre and exhausted portions come off the print near the borders. Duration of contact with emulsion is around 1-2 sec. This method gives ABSOLUTELY even development to any lithable paper. Now I can completely control edges of cold-tone lith prints! Arthur Suilin Russia.
Printing on Slavich papers. I live in Russia so many lithable papers described by Tim Rudman are not available here. But we have Slavich Unibrom paper. It can give excellent prints with unique tonality between Forte Bromofort (very cool, almost grey) and Sterling Lith (warm, beige). Depending on developer, the tone varies from yellowish-grey to pinkish-brown. Shadows are much colder than highlights, grey or brownish-grey. Dilute ferricyanide bleach shifts highlight tones from yellow to pink, leaving cool grey shadow tones. In gold toner, highlight tones shift to lavender, lilac, and violet. Unbleached print gives tones from lilac to blue. Anastasia Medvedeva Russia.