How to tell if metol (in powder form) has gone bad

[Ben Calwell]

I have a jar of metol (powder) that I bought about three years ago to use in making D-23. Haven't mixed any D-23 recently, but when I looked at the jar of metol today, I noticed the color had changed. It's gone from white to light brown. Does this color change mean it's no longer any good?

[Doremus Scudder]

If the Metol powder is only light brown, it should work fine. Of course, the test would be to mix some D-23 and develop a small piece of film (leader or the like) in daylight to see if the developer is active. Since Metol is the only developing agent in D-23, this should tell the tale. The test would be even better if you had previously done the test and had a benchmark for developing in fresh developer. I'd bet your Metol is good; mine is the color of light sand and it works just fine.

Doremus

[koraks]

Light brown/tan should be fine.
You may want to reconsider how you store it if it shifted much in color within 2-3 years.

[BradS]

This came up a while back too and iirc, the chemists said that light gray (and pink???) are also ok.

[LabRat]

If it's inky blue/black, it's bad...

Steve K

[Jim Noel]

Mine is stored in glass at a relatively constant 72deg. It is barely light tan.

[Ben Calwell]

Thanks, everyone. I’ll go ahead and mix up a batch.