I want to know what is the optimum pH (in film developer) for Glycin and Metol respectively.

Regards Xosni

-- Xosni (xosni@gega.net), October 16, 2001

Answers

The activity of any developer tends to increase with its alkalinity (higher pH value), but I've never heard of, or seen, a table of 'optimum' pH value for a particular developing agent.
Most film developers have a pH of between 8.5 and 10 at their working strength.
All I can add is that both Metol and Glycin are regarded as soft working, low activity developers. Both will work with Sulphite alone as both the preservative and alkali, so I guess they're at their best at around pH 8.5 to 9.
When they're compounded with other developing agents, like Hydroquinone, that's a completely different matter.

-- Pete Andrews (p.l.andrews@bham.ac.uk), October 16, 2001.

In my article on Mixing Developers at http://unblinkingeye.com/Articles/Developers/developers.html, under the heading "Accelerators", I provide pH values for various alkaline agents at standard dilutions. You might study some standard metol and glycin formulas to see how much of various accelerators are used, and from that derive approximate pH values.

-- Ed Buffaloe (edb@unblinkingeye.com), October 16, 2001.