You don't need to do a lot of testing with TP if you're just going to use Technidol: EI 25 and use the time in the box of Technidol. If you can expose slide or Polaroid film successfully then you'll be fine with TP as far as exposure latitude goes.(posted 8893 days ago)I wouldn't even worry about using a fine-grain developer with TP (who does?). Even Dektol can't make TP grainy. The only reason I can think of to stray from Technidol (which most decent camera shops stock) for most photographic purposes is to get more tonal range or to get a pyro stain.