I wanted to test some 35mm KODAK TRI-X 400 found in fridge using my Home-Made 510-Pyro -- looked up Massive Dev Chart = it said '8mins' 1+100 @ 400 but I did a short length from 800ASA to 100ASA in my PENTAX KX having tested shutter -- set 1/500th and altered the APERTURE to alter the exposure. I gave the 8 mins and on fixing in Alkaline Fix negs were GHOSTLY THIN !