Unusual developer sludging

[chris_raney]

<p>I am thrilled with the results I've been getting from using David Vestal's version of divided D-76, and I have no reason--especially in a tropical climate--to change formula. So...forget the sales pitches for your favorite developers, please.</p>

<p>That said, something that has been troubling me is that once solution A has been used (I shoot Tri-X almost exclusively) then returned to the (glass) bottle it will, within a day or two, turn into an cloudy-gray sludge; awful little flakes of schmutz can often be seen floating in it. Unused, in it's glass container, that developer will remain clear and viable for months. Introduce it to film, though, and it goes bad, quickly.</p>

<p>I doubt I can do anything about it without drastically altering the outcome of my development, which I will simply not do. But is this some sort of oxidation that's taking place because of that nasty purple (anti-halation?) dye now being used in Tri-X film? A lot of that dye is leached out whenever I run the film through the clearing stage. And even when I use my wetting agent just before I put the film in the dryer it will frequently discolor the the wetting agent (LFN). This discoloring of my chemistry, though, does not occur during the fixing stage ( Kodak F-5).</p>

<p>What's happening here, wizened chemical heads? </p>

[jay_de_fehr]

<p>Chris,</p>

<p>Your sludge is anything but unusual. D-76 relies in part on physical development for its fine grain characteristics. Physical development is accomplished by silver freed in the development process by the solvent action of sodium sulfite being redeposited on the film. Some of this silver, along with other developer products, remains in the solution as sludge. If you use D-76 one-shot, you'll never notice the sludge, but if you use it stock/replenished, you might. I don't think the dye has much to do with your sludge. You could probably eliminate much of the sludge by pouring through a filter when returning the solution to its storage container. </p>

[leicaglow]

<p>As Jay indicates: I seldom re-use developer because I don't like deposits on my next batch of film. But there are times when I haven't received a shipment of new developer in, and I will use replenished stock. I always pour it through a coffee filter before using it again. And it is, indeed, very common with D-76, and not really that big of deal.</p>

[leighb]

<p>If you're getting anti-halation dye in the photo-flo, you're not washing the film properly.</p>

<p>The dye should be completely removed in the washing process, and part of it in earlier stages.</p>

<p>There should be absolutely none left by the time you get to the photo-flo.</p>

<p>Regarding your developer issues...<br>

It's always wise to filter any chemistry being returned to its bottle, to remove physical contaminants.</p>

<p>- Leigh</p>

[Alan Marcus]

<p>The developing agents used in the Kodak D-76 formula and its uncles', aunts' and cousins' are all related to benzene, initially extracted from coal tar. Today these agents are syntheses in the laboratory but retain their coal tar personality. Developing agents have an affinity for oxygen and when oxidized revert to coal tar. Additionally as they oxidize, a catalyst is generated that speeds up oxidation. The formula thus contains a preservative that retards oxidation and neutralize staining oxidation products thus keeping the solution clear. The preservative is sodium sulfite and it and its byproducts play no significant part in image formation . The preservative works by forming various organic compounds and sulfite salts that also slows the formation of the harmful catalyst. Replenisher formulas bolster spent preventives and developing agents etc. </p>

[craig_shearman1]

<p>I've used D-76 and Tri-X for more than 30 years with excellent results, so congratulations for sticking to a tried and true standard. But my developer never, ever goes back into the bottle. It gets used and goes down the drain. My philosophy is that developer is too cheap and the photos I shoot too valuable take the risk of squeezing a few extra pennies out of the bottle.</p>

[chris_raney]

<p>Thank you all, and yes, I do filter those chemicals that get re-used, like my Vestal solution A and my fixer. And Leigh, after fixing the film goes immediately into a heavy sodium sulfite solution and agitated for a full five minutes. Then it goes into the washer for 20 minutes. That purple dye is STILL leaching slightly by the time it goes into the LFN--I don't use Photo-Flo on my film. </p>

<p>The residual purple isn't the problem. The problem is that I can't just develop one or two roll of film without having to sacrifice an entire quart of solution A. Oh, sure, I can run many rolls though a single bottle of solution if I'm doing a marathon development, but once that solution A used at all--even for a single roll of film--as I've pointed out, it's toast. That's why I always keep three quarts on hand. </p>

<p>I purchase my sodium sulfite in 50 pound buckets. Might have to start doing the same for metol and hydroquinone! (sorta kidding)</p>