And while we’re getting all retro and talking about film chemistry, the original D-76 formula has a basic problem - the classic formula is more alkaline immediately after you mix it and ideally you should mix it, let it ‘settle’ for 24 hours, then use it. Kodak’s more recent versions are buffered to prevent this, and the nicest version you can make yourself is buffered D-76:
Water (52°C) 750mL
Metol 2g
Sodium sulfite (dry) 100g
Hydroquinone 5g
Borax 8g
Boric acid 8g
Water (room temp) to make 1L
Add the chemicals in this order and stir until dissolved before adding the next. Let it come back to temperature before using.
This is essentially infinitely scalable, and I also used to sometimes make it in 50L batches. Borax-boric acid buffers are great, and the pH increases with dilution so buffered D-76 1+1 and 1+3 work really well.
There were several photo chemistry sites back in the day. Whenever I posted a formula if what I posted was even vaguely like anything one particular site owner had on his site, he would send me the most awesomely abusive messages, usually claiming I ‘stole’ from him. I generally responded by sending him scans of the original Kodak documents, or my work SOPs where they were not confidential, or direct him to an online scan of The Darkroom Cookbook. I wonder if I’ll hear from him now? But maybe he’s gone to the big darkroom in the sky.
www.freestylephoto.com
