Homebrew PCBs

> Jon wrote:
>
> It is Kodak Rapid Fixer, really sold for
> print paper <SNIP>
> The film looks great after development,
> completely white with black marks where
> intended.  About 5 seconds after putting
> it in the fixer, I can see it starting
> to darken.
> 
> I am quite sure the film is not SUPPOSED
> to look like this, as the pink-orange
> color is blotchy.  I would expect it to
> be very consistent if it was the
> intentional color of the backing.

Long ago I saw some high contrast paper
that went light yellow in the acidic
rapid fixer.  It had to be used with
non-rapid (hypo) fixer.

Or it could be something that happens to
the film when old.