Quote Originally Posted by Kami-the-Trout View Post
I'm about to give a go at making a basic emulsin to coat on glass for my 13x18 plate camera. I've assembled all the bits and pieces (including a magentic hot plate stirrer) and have a coupe of questions.

1. If my darkroom safe light (red) is safe enough to not fog paper for several minutes, is that dark enough for emulsion mixing purposes? How do I know if the light is OK? I don't want to mix in the dark . . .

2. All the recipes say to add silver to the gelatin slowly, to increase the speed. A quick dump increases contrast at the expense of speed, as I understand it.

If I like the idea of contrast more than speed, is it OK to do a quick add? How slow would that likely make the final product? Any idea?

3. There are a variety of recipes to try, each with slightly varying amounts of silver nitrate to gelatin to pot. bromide/iodide. Is there a guideline that suggests more silver is better/worse, contrasty/less contrasty, faster/slower, etc? I'm trying to decide which recipe to do first.

4. Most recipes call for thymol as a preservative. I don't have that yet. Is it absolutely crucial, or can i do a batch without it, and still expect some longevity from the emulsion? Or should I wait until I get it?
The advice already given is far more knowledgable that I could give, but I do have the experience of a novice trying to figure it out.
1. Don't worry about your safelight. My emulsion takes 1 minute of a 1watt red LED set on the emulsion iteslf to fog.
2. I think you will find the contrast satisfying even with a slower dump. My contrast is more dependent on the quality of coating than the makeup of the emulsion. ( I guess, to be technical, that would be Dmax, rather than contrast, I find my emulsion similar to the Arista Ortho Lith film when developed in continuous tone developer. I find the quality of the coating has far more to do with the final print than anything else)
3. I've tried PE's SRAD and a few others. They all take pictures, my advice is to pick one and get some practice coating it and making reproducible results.
4. While others cite shorter lifespans, I've left coated plates in room temp for over a month with no discernable difference in the quality of the neg and I use no preservative. I don't think preservative is critical.