The color of Pyrocat-PC Stock A

[Bruce Osgood]

I suspect my Pyocatchin (Catechol) has gone bad. It was a slate grey.

When I diluted (electric hand-mixer) it in 900 mL Propylene Glycol at +150-F it turned nearly black in color.

I continued with ascorbic acid (4g) and p-Aminohenol (5g) and mixed another 15 minutes.

It is an opaque golden-amber color and you cannot see the therometer standing in it.

Is this about right?

 

[sanking]

I suspect my Pyocatchin (Catechol) has gone bad. It was a slate grey.

When I diluted (electric hand-mixer) it in 900 mL Propylene Glycol at +150-F it turned nearly black in color.

I continued with ascorbic acid (4g) and p-Aminohenol (5g) and mixed another 15 minutes.

It is an opaque golden-amber color and you cannot see the therometer standing in it.

Is this about right?

Hi Bruce,

There is a good chance that the developer is ok in spite of the deep golden amber color. Normally the developer is a very pale amber or light yellow after mixing in glycol, but many factors can affect the final color. It may change further in color with age but this does not appear to interfere with the working characteristics of the developer. A Pyrocat-PC solution that I mixed about six months ago was very light yellow just after mixing, but is now a fairly dark maroon color but still works perfectly. Hope I don't confuse it with the Zinfandel!! The chemical Pyrocatechin chemical itself is slightly off-white or light beige when fresh. Slate gray is probably ok.

Just run a sacrificial roll of film through the developer and see what happens. If it works now it will work fine for several years.

Sandy

 

[Bruce Osgood]

Thank you Sandy,
I'm just about to test try a couple of sheets of Bergger BPF200 (4X5) which I will develop in my Jobo CPE2. It has but 1 speed and you had suggested I might try 1.3 + 1 + 100 to compensate for the rapid speed. I think that is what I'm goingto do.