Pyrocat HD or in Glycol?

[John Kasaian]

Since I'm doing some 'spirimenting with developers, what is the difference between the two? Which one would work best for rotary processing? Thanks!

[sanking]

Since I'm doing some 'spirimenting with developers, what is the difference between the two? Which one would work best for rotary processing? Thanks!

The difference is only in shelf life of the Stock A solution. Pyrocat-HD in water has a shelf life of 8-12 months in partially full bottles. The shelf life of Pyrocat-HD in glycol is several years, at least 3+.

Pyrocat-MC, which is only available in glycol, is an entirely different developer in that the seconary reducer is metol rather than phenidone and it also contains ascorbic acid to reduce oxidation. The stain, which is orange/brown in comparision to the brown stain of Pyrocat-HD, gives greater UV blocking. It also gives greater acutance in rotary development than -HD. It is my choice for rotary development, especially for alternative processes where development times are very long since proportional stain is high and B+F stain is very low.

Sandy King

[John Kasaian]

Thanks Sandy!

[Mike Castles]

Good information, Sandy...do you know the shelf life of part B? Is it the same as part A in water, or does it go off sooner (and how does one know)?

[sanking]

Good information, Sandy...do you know the shelf life of part B? Is it the same as part A in water, or does it go off sooner (and how does one know)?

Mike,

The shelf life of Part B, which is a 75% potassium carbonate solution, is several years if mixed in distilled water. Part B is the same for both Pyrocat-HD and Pyrocat-MC.

Sandy

[Andrew O'Neill]

Part B last indefinately. As far as mixing up part A I, only use distilled water as I go through 500ml in about 5 months.

[Mike Castles]

Thank You Sandy, was hoping to hear that. Always distilled water, but have been thinking of giving the glycol a go (after reading your comment about -MC, may just give it a go).

[steve simmons]

The other staining developer that works well in this type of sitation is Rollo Pyro. It mixes with water so you dont have to worry about different versions. Give Bostick and Sullivan or Photographer's Formulary a call before making any decisions.

steve simmons

[rachase]

Thanks for the info, Sandy. I have been getting excellent results using HD in Glycol for my FP4 with the JOBO CPP2/3010 combination. I may give the MC a try to compare acutance.

Steve, isn't Rollo Pyro a different animal with respect to stain color and, for that reason, may have some significant printing ramifications?

[steve simmons]

Rollo Pyro is a variation of PMKspecifically designed for roller processing.

steve

[rachase]

Right, but in addition to Rollo Pyro being suited for roller processing, it uses pyrogallol rather than pyrocatechin and therefore has somewhat different staining properties. One may produce better results than the other depending on printing specifics.

[tim atherton]

The other staining developer that works well in this type of sitation is Rollo Pyro. It mixes with water so you dont have to worry about different versions.

steve simmons

Pyrocat -HD mixes with water (at least that's what I mix it with)? Mixing part with glycol - which I've never bothered with - just seems like another option.

As I understand it Pyrocat MC is a different developer isn't it?

[sanking]

Pyrocat -HD mixes with water (at least that's what I mix it with)? Mixing part with glycol - which I've never bothered with - just seems like another option.

As I understand it Pyrocat MC is a different developer isn't it?

Pyrocat-HD mixes easily in water, and when mixed with distilled water it's shelf life is 8-12 months in partially full bottles. Mixed with Glycol the shelf life of Pyrocat-HD is on the order of many years. And as I noted earlier, there is no difference in the development characteristics of Pyrocat-HD, whether mixed in water or glycol.

And yes, Pyrocat-MC is not just a variant of Pyrocat-HD, but an entirely different formula. Persons who understand developers could look at the formulas and immediately understand that fact. The active reducers in Pyrocat-HD are pyrocatechin/catechol and phenidone, in Pyrocat-MC the active reducers are Pyrocatechin/catechol, metol and ascorbic acid.

Sandy King

[j.e.simmons]

John, to answer your original question, I have not seen any difference in Pyrocat HD mixed in water or in glycol other than longevity. I once had a bottle of the water mixed version go bad after about nine months. I use brush development which is continuous agitation, as roller development is.

Pick one and use your time for playing long tones.
juan

[Mike Davis]

J
Pick one and use your time for playing long tones.
juan

John, I picked one (HD for several years), but you can only play tones so long on the tuba.

Mike