Developer Color Change

[farzin_darihaki]

<p>Hello everyone,<br /> I've had a 4-liter non-diluted developer. It was an old product from a native company, originally in powder form.<br /> I've used more than half of it during 4-5 months, developing three expired films. I've tried my best to keep air out of the storage tank, and kept it in a dark, cold place.<br /> Two months ago when I was wanted to develop an expired (12/2008) Kodak Tmax 400 (the last of those three films) with it, I saw the developer has a yellowish color. The thing that I didn't see last two times. I took the risk and did the process. The result was not bad, except a few spots (seen like rust) mostly out of the frames.<br /> These three films are the only ones that I did the process myself and I have a little experience on this. So I want to know is the developer's color change due to long time storage or not? and should I use the rest of it?<br /> Thanks for any suggestion,<br /> Farzin</p>

[chris_waller]

<p>If it's turning yellow then it's oxidising. It may still work but its activity will be reduced. I seem to remember that Ilford recommend using film developer within 4 weeks once the container is half-full or less, even if tightly capped.</p>

[glen_h]

<p>I would call the color of bad developer brown, not yellow. A very light tan color is pretty usual. Even at an ordinarily light tan, it should be fine. </p>

<p>If it looks like mud, or is on the way to mud, it is bad. (That is, you can't see through it.)</p>

<p>With T-max, your developer will often turn pink. That is usual, it is the sensitizing dye from the film.</p>

<p>Well stored, in full bottles, it should last longer than they say.</p>

<p>But I recommend Diafine which lasts close to forever with reasonable storage. I always be sure to get the air out, but it oxidizes pretty slowly anyway. Mine is now over three years old.</p>

[Alan Marcus]

<p>Most all developers are spin-offs of benzene. Chemically they are the benzene ring with side chains. <br>

Benzene was initially obtained from coal, now it is synthesized. Nevertheless, developers as the oxidize and otherwise breakdown, revert to coal tar. Thus spent and exhausted developers take on a dark perhaps black coloration. Initially they are clear solutions commonly they resemble tea. A key ingredient of developer formulations is a preservative. The preservative retards aerial oxidation and neutralizes staining agents. As the developer ages, the preservative is consumed and oxidation triumphs. The solution darkens and finally tar balls form. </p>

[farzin_darihaki]

<p>Thank you Chris, Glen and Alen.<br>

I was not sure if it is because of oxidization or something else; like reaction with the container, as its color became pretty the same as the container.<br>

Recently I've received an Ilford ID-11, so I conclude it's better to use that one.</p>