Homebrew PCBs

In article <4D6F23AB.6050501@...>,
   Jon Elson <elson@...> wrote:
> but somebody there said to dilute the fixer.  I tried that, didn't seem
> to make any difference. I am using Kodak rapid fixer,

It's quite an interesting phenomena. 

You could try changing the fixer completly of course. Most rapid fixers
are based on Ammonium Thiosuphate, often with additional (proprietry)
additives, instead of the traditional Sodium Thiosulphate but I would not
have thought there would have been such a result.

It can do no harm to experiment with a simple fixer.

This is about as simple as you can get:

240g Sodium Thiosuphate.
10g  Sodium Sulphite (anhydrous)
25g  Sodium Metabisulphite

Made up to 1l water. (pure if possible)

This is non-hardening and contains no acid to arrest development.

Are you using a stop bath and are you rinsing well between processes?

-- 
Stuart Winsor

Midland RISC OS show - Sat July 9th 2011