Catechol color in PF Pyrocat kits

In my experience, the catechol included with the dry PF kit has ranged from light tan to grayish green. I've never had development problems that seemed to stem from an entirely bad batch, and in most cases the solution (in DI water) never took on a dramatic color.

My latest kit (arrived today) contained catechol which was greenish purple. After mixing w/ propylene glycol, solution A is DEEP purple, as in Dimetapp or grape soda purple. I'll give it a shot later tonight on a couple sheets, but are these colors indicative of impurities or catechol breakdown prior to mixing? The glycol was heated to 140F before the sodium bisulfite, catechol, phenidone, and potassium bromide were added, then allowed to cool. The glass bottle it's in received a thorough rinsing beforehand. Any thoughts?

Kerey K. Barnowe-Meyer
www.kerey.com

I have never seen anything like this, even in mixing with propylene glycol.

Maybe someone else can offer some suggestion as to why this would happen.

Sandy

kerey said:

In my experience, the catechol included with the dry PF kit has ranged from light tan to grayish green. I've never had development problems that seemed to stem from an entirely bad batch, and in most cases the solution (in DI water) never took on a dramatic color.

My latest kit (arrived today) contained catechol which was greenish purple. After mixing w/ propylene glycol, solution A is DEEP purple, as in Dimetapp or grape soda purple. I'll give it a shot later tonight on a couple sheets, but are these colors indicative of impurities or catechol breakdown prior to mixing? The glycol was heated to 140F before the sodium bisulfite, catechol, phenidone, and potassium bromide were added, then allowed to cool. The glass bottle it's in received a thorough rinsing beforehand. Any thoughts?

Kerey K. Barnowe-Meyer
www.kerey.com

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I agree with Jay's observation. Colored solutions generally indicate oxidation or contamination of the chemicals. Of course, strange colors can result from heating the glycol solutions so there me food dyes or something in there causing the color.

Let us know how your negatives come out. I am very interested to learn more about this.

Sandy

jdef said:

Hi Kerey.

I use Hypercat, which is a catechol developer formulated to be made up in glycol. In my experience, oxidised catechol runs from amber to reddish brown. Hypercat concentrate is very clear. Colored solutions generally indicate oxidation or contamination of some kind, and the color can be a clue to the form of contamination, or the oxidized agent. Since the catechol in your kit was green-purple, it's a safe bet that it is the source of the color. The contamination might or might not affect the working properties of the developer, as a very small amount of contamination can produce a lot of color. In any case, it's not likely to degrade further. Good luck.

Jay

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didnt Bostick and Sullivan have an issue with weird colors too. I think Jeremy Moore had some problems with the readymix pyrocat hd. They replaced it right away and I have not heard anymore from him about it.

lee\c

Well, things came out pretty well... though I'm not sure why. I did two batches just to make sure (2 and then 6 4x5 sheets of 100 Delta in a hand-inverted Jobo) and, despite some overexposure issues which deserve a new thread, development seems to have gone normally.

The A solution gradually cleared to a smokey gray, much more clear than immediately after mixing but still much darker than I've seen before. The mixed working solution (1.4 liters) was a forest green. The spent developer (11 minutes at 73F) was a strange urine-like yellow. Are these colors typical when using propylene glycol and Delta films? I usually do my mixing (using distilled water) in opaque bottles and rarely stop to check the color of the spent developer.

I've also noticed a crystalline compound in the A stock solution. At least some of it refuses to go into solution... perhaps the rest is causing the color change. It doesn't seem to have had any effect on development, although many of the particles are large enough to clog the tip of a 5mL volumetric pipette.

When I received the kit, I also discovered the sleeves containing both the phenidone and the sodium bisulfite weren't properly sealed. The phenidone looked to be all there, but nearly half the bisulfite coated the rest of the internal packaging and instruction sheet. Based on Anchell/Troop and some comments I've found here, I figured this wouldn't matter too much since I was mixing A into glycol. So despite the apparent contamination of catechol, potential contamination of phenidone, and insufficient bisulfite, it could have been worse. I should add too that I've never had problems with packaging in the PF kit before, and don't expect to in the future.

My big decision now is whether to stick w/ this stock or ditch it and remix another batch. :confused: Isn't this fun!!

Kerey

jdef said:

Hi again Kerey.

I'm going to go out on a limb and guess that your kit included glycin instead of catechol. Glycin turns deep purple when oxidized, but looks much like catechol in dry form. Your developer will still work, but there will be no stain, and its characteristics might be far different than those of Pyrocat HD. It might be a good substitute for Rodinal. I hope you'll let us know how it turns out.

Jay

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Hmmmm. I've only developed one sheet in something other than Pyrocat in my entire life (I started out with this whole B&W developing thing last year). But in comparing these current negs with my lone DD-X neg, they looked stained to me. I don't know what a glycin negative would look like, but the subtle brown color and 'look' are similar to my previous Pyrocat negs... unless I'm the victim of a long-term Formulary glycin experimental trial. :rolleyes:

kerey said:

I've also noticed a crystalline compound in the A stock solution. At least some of it refuses to go into solution...

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Ionic compounds like sodium bisulfite and potassium bromide are only slightly soluble in glycols. I suspect that not all of the bisulfite went into solution. In general ammonium compounds are more soluble in glycols. I use ammonium bromide rather than potassium bromide when mixing developers in propylene glycol.

Then, too, with a divided developer like Pyrocat or PMK, the bromide and sulfite or bisulfite may be put in the second solution. The main purpose of the sulfite in the first solution is for preservation of the developing agent which function is well done by the glycol. The less sulfite in the working solution, the stronger the proportional stain image. I don't think there is enough sulfite in the original working solution to change the granularity. I don't remember if it has an effect on tanning, but if it does, it can certainly be added to the second solution.

I have noticed odd colors with catechol - It never effected its use. With pyrocat, I notice the water turns blue when I add the A solution and it turns amber when I add the B solution and of course the exhausted color is dependent on the type of film I develop - With Tri-x sheets, It is usually a dark brown going down the drain.

I'm with Pat Gainer on this one. I mix my Pyrocat A solution in Propylene Glycol - with No bisulfite and no KBr. It keeps forever that way.

I mix the B solution (Sodium or Potassium Carbonate) in water - not glycol. If I want to use bisulfite and KBR (I've done it with and without) I add them to the B solution

I would be careful about using Ammonium Bromide in a developer. That ammonium ion is a great silver halide solvent and will affect the image strongly.

PE

jdef said:

Hi Kerey.

Glycin won't stain, so I must have guessed wrong. As long as the developer is working as usual, I wouldn't worry about the various color changes. Catechol in carbonate turns greenish, and then brown with oxidation, and different films use different backing dyes, which aren't bleached by the small amount of sulfite in Pyrocat HD, so things can get pretty colorful. I'm glad your developer is performing normally. Enjoy.

Jay in Caldwell

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Caldwell? No kidding. Thanks for your and everyone's help. If the solids I'm seeing are indeed bisulfite, and the negatives are coming out ok regardless, I suppose I'll keep on using it. Someday I'd enjoy seeing what 'pure' catechol looks like... assuming the discoloration is, in fact, the result of some secondary compound.

Thanks again!

Kerey

kerey said:

Caldwell? No kidding. Thanks for your and everyone's help. If the solids I'm seeing are indeed bisulfite, and the negatives are coming out ok regardless, I suppose I'll keep on using it. Someday I'd enjoy seeing what 'pure' catechol looks like... assuming the discoloration is, in fact, the result of some secondary compound.

Thanks again!

Kerey

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Catechol is a white to tan solid. It's been a long time since I worked with it in the lab though.

UPDATE NOTE:

Photographers' Formulary just unexpectedly delivered not only a replacement kit but also another pint of glycol. I developed another batch of film last night using the same stock solution, and everything came out beautifully. All of the additional mixing help you guys and gals have provided has been great!

Kerey

While it is true that a Pyrocat-HD solution mixed in glycol without the sodium metabisulfite and potassium bromide would work, the results would be slightly different. Without the bromide the B+F would be slightly higher, and without the sodium metabisulfite the energy level would be lower, i.e. for any given dilution you would need longer development times.

Sandy King

jdef said:

Hi Kerey.

The bisulfite is supposed to serve two purposes in Pyrocat; to preserve the stock A solution when made up in water, and to control general stain. The KBr is supposed to reduce fog, and possibly grain. I'm sure that both could be left out of a glycol solution, but there might be a slight increase in general stain and fog that could veil your shadows. I took a different approach with Hypercat, using ascorbic acid and BZT in place of the Sodium metabisulfite and potassium bromide. Ascorbic acid and BZT dissolve at the same temp as the catechol, making a very clear, sediment-free solution. I'm working on a similar developer that will eliminate both the ascorbic acid and BZT from the formula, work at a lower pH, and at the same time give a more active developer, that is virtually fog-free. My preliminary testing suggests it might be an excellent choice for rotary development or reduced agitation techniques. I still have a lot of testing to do, but if it holds together, I'll post the formula somewhere.

If you ever get down to the Boise area, look me up.

Jay

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