Liquid Pyrocat-HD at PhotoFormulary

[Dean Cookson]

I thought folks might be interested in this:

I got mail from the nice people at The Photographer's Formulary today announcing that they've started selling a liquid Pyrocat-HD kit. They've got a 10L and a 50L kit and when I emailed a question about the overly strong B solution in the dry kits they said they've both changed the dry kits and mixed the liquid kits to match Sandy's formula.

FWIW, I have no affiliation with the PhotoFormulary and I'm only 3 sheets of film into the liquid Pyrocat-HD kit I bought from B&S a couple of weeks ago.

[steve simmons]

We will compare PMK and HD developers in the July issue of View Cmea. Here are my preliminary findings

sharpness - PMK is a little sharper, grain - PMK is slightly grainier, stain - HD creates a cleaner film base (less overall stain) than PMK, film speed - about the same but PMK gives slightly better shadow detail, local contrast - undecided at the moment.

steve simmons

[sanking]

I look forward to the reviews in View Camera.

Here are my own observations, based on both practical field comparisons and sensitometric testing. Bear in mind that I used PMK for over ten years as my main developer before developing the Pyrocat-HD formula.

Let me mention one issue of paramount importance in comparison of developers. The films *must* be developed to the exact CI, or contrast, and that is *effective printing contrast.* And that is not particularly easy to achieve unless one uses control procedures such as step tablet controls. My comments, which are based on comparison of PMK and Pyrocat-HD at the same effective printing density, area s follows.

1. Sharpness -- With constant and intermittent agitation I can see no difference in either resolution or sharpness between PMK and Pyrocat-HD. However, negatives developed in Pyrocat-HD with minimal agitation procedures are sharper than those developed with constant agitation because of an increase in micro-contrast. Minimal agitation would not be recommended for PMK because of its tendency to stain without vigorous agitation.

2. Grain -- Pyrocat-HD has slightly finer grain than PMK.

3. EFS is about the same, but Pyrocat-HD gives about 1/4 stop more emulsion speed than PMK with some medium speed films, including FP4+. Field tests would be inconclusive with differences this small because of the inaccuracies of the exposing equipment. I base my EFS on light integrated based exposures.

4. Development times -- PMK times for the same CI are about 15-20% longer than those for Pyrocat-HD for silver printing, and 30-40% longer for printing with UV processes.

5. Stain -- Pyrocat-HD gives a cleaner stain with most films than PMK. Also, the color of the stain is different and if development is such that PMK and Pyrocat-HD negatives print with the same CI with graded silver papers the Pyrocat-HD negative will print with much more contrast with UV processes such as Pt./Pd. (the brown stain of Pyrocat-HD is a more effective filter of UV light than the yellow/green stain of PMK). This makes Pyrocat-HD negatives much better dual-purpose negatives for persons who would like to print with silver papers and Pt/Pd.

6. Rotary processing -- A working solution of Pyrocat-HD oxidizes much less rapidly than a working solution of PMK. For this reason Pyrocat-HD gives in general better results with rotary processing, as in Jobo or BTZS tubes. Most people who have switched to Pyrocat-HD from PMK have reached the same conclusion.

In my opinion if one were to limit a comparison of PMK and Pyrocat-HD to silver printing of tray processed negatives there would be little if any difference in results. Where I find Pyrocat-HD to be really superior is as follows: 1) rotary processing, 2) can be used with minimal agitation procedures for the enhancement of micro-contrast, and 3) better for making dual-purpose negatives intended for both silver and Ptd/Pd printing.

[Paul Metcalf]

Don't know if this is possible, but given all of the discussions on film and developers (esp Pyro), maybe a session at the next LF conference (whereever it may be) on this topic is warrented. I envision some sort of negative "sharing" sort of session where actual negatives can be viewed, discussed and visually compared between different methods, materials AND developers (people). Maybe even something like what Bruce Barlow did with paper and paper developers, but with film. It would nessitate having light tables, but that could be worked, I quess. Gordan Hutchings had a few of his negatives at his session on PMK at the first LF conference (in Albuquerque) which was very beneficial (I didn't attend this year's session of his so don't know if he did the same). Just like with prints, it goes without saying (but I will anyhow!) that seeing the real thing in person makes a big difference. Just a thought.

[steve simmons]

Gordon Hutchings did another session n The Art and Craft of Black and White in Monerey.

I will look at your suggesions and may do an article in an upcoming View Camera looking even mor closely nd different developers and how they make images on film.

steve simmons

[Andre Noble]

Steve, did you mean to write "Moneyrey"?

:-)