Is Rollo Pyro only for rotorary processing?

[brian steinberger]

I'm using Rollo Pyro to process 4x5 film in a Jobo 3010, but I also process 120 film, two reels at a time in a stainless steel tank. Can I use Rollo Pyro for this purpose even though it's no continuous agitation? Is it true that Rollo Pyro is PMK but with and substituted additive (vitamin C) which helps to not oxidize so quickly?

[Kerik Kouklis]

I use rollo in trays all the time. Works great.

[Andrew O'Neill]

Rollo was formulated for constant agitation but you shouldn't have any trouble using it with intermitant agitation in a tank.

[brian steinberger]

But would regular PMK be better for intermitant agitation?

[Jay DeFehr]

But would regular PMK be better for intermitant agitation?

Hi Brian.

In my opinion, no. I posted a more detailed response to your question at pnet.

Jay

[Geary Lyons]

It depends on what you are trying to achieve. Rollo pyro will develop the roll film in a normal inversion tank, yes. But the stain will be, most likely, mimimal. Rollo was developed to operate in a constant rotation, lower developer to air space environment.

If you want pyro stain, better to use PMK or Pryrocat HD.

Cheers,
Geary

[Jay DeFehr]

Geary,

Have you actually measured the stain produced by the developers you mention? When corrected for general stain, the differences in image stain produced by these developers are insignificant.

Jay

[sanking]

But would regular PMK be better for intermitant agitation?

IMO, yes, though the answer depends on what "better" means for you. Rollo Pyro is a much more concentrated developer than PMK and at the recommended dilution develops film to a higher CI much faster. Rollo Pyro also contains ascorbic acid, which further speeds up the action and reduces oxidation. However, the ascorbic acid is synergistic with pyrogallol/metol and for any given dilution there should in theory be less local exhaustion with Rollo Pyro than with PMK, thus decreasing edge or adjacency effects, and acutance. In practice I believe this is the case because in my experience PMK gives more acutance than Rollo Pyro with intermitent agitation, say shuffling in a tray. Just for the record, my experience is based on contact printing LF and ULF negatives, not on projection printing.

Sandy King

[Geary Lyons]

Geary,

Have you actually measured the stain produced by the developers you mention? When corrected for general stain, the differences in image stain produced by these developers are insignificant.

Jay

Nope, not into densitometry. Purely anecdotal. IIRC, my negs, with Rollo in Nikkor tanks, visually had far less general stain and appeared more contrasty than the same brand of 120 film processed in the jobo. I had to compensate during printing. It was an "out of town stop gap", not to be repeated.

Haven't used PMK since I went jobo quite a few years back. I have never used Pyrocat HD, but folks whose skills I respect do.
Cheers,
Geary

[Jay DeFehr]

Hi Geary.

Maybe it's just a difference in interpretation. Higher contrast indicates more stain, in my experience, and not less, but the low general stain can significantly reduce the apparent stain, and those accustomed to the general stain produced by PMK can misinterpret negs without apparent general stain as having less stain, and sometimes be surprised by the printing contrast of those negatives. It is a mistake to believe that since PMK produces more apparent stain with rotary processing, that it follows logically that developers producing less general stain with rotary processing also produce less image stain with intermittent agitation than they do with rotary processing. Staining developers that work well with rotary processing are superadditive developers, and retain film speed with rotary processing because they include metol or phenidone which are regenerated by pyrogallol, catechol and ascorbic acid, as they oxidise, and might form secondary products that accelerate development. As Rollo-Pyro demonstrates, PMK is unsuitable for rotary processing solely based on the amouint of general stain it produces with rotary development, and not because it doesn't retain film speed with contraction development. Single agent staining developers, like Hypercat, rely on local exhaustion of dilute developer solution to produce full film speed, and are not compatible with rotary processing, except when using a very active alkali like sodium hydroxide, which elevates fog levels but rotary processing eliminates the advantages offered by tanning/staining, single-agent acutance developers, which are best suited to intermittent agitation and thin, slow, contrasty films. Superadditive developers are far more general purpose, user-friendly, and versatile than single-agent developers, but can't deliver the maximum sharpness that a true acutance developer can. Choosing the right tool for the job (when available) will result in less frustration and the best possible results, and I think you've chosen a good developer for your application. Good luck.

Jay