I've recently tried fogging the litho film I use to lower its contrast. It appears to be working.
I've done some test exposures with a Stouffer step tablet in the darkroom. I'm able to get an 18 step range and maintain good speed, an ASA of at least 12. I took some shots with a pinhole camera and the results look promising. I cam able to get much more shadow detail that I was able to previously. To do the fogging I use my enlarger in the darkroom. I did a number of test exposure's to determine how much exposure the film can take before it starts to fog. I fog the film at an exposure a stop less than at what it begins to fog at. I stick it in the camera and shoot as normal and process as normal. I think I may be able to use this technique to boost the speed a bit. I will try fogging at a somewhat higher exposure to see if this increases the speed. Here's my hypothesis: Litho film seems to have a threshold exposure level, any exposure below this isn' recorded. Flashing, or fogging the film may bring the exposure level to the threshold so that very little additional exposure is needed to record an image. I'm wondering if anyone else has tried this, and what their experience is. Gord --------------------------------------------------------- Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca 112 Science Place http://duke.usask.ca/~holtsg University of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 ---------------------------------------------------------
