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View Full Version : Your experience with Pyrocat-M???



Bob Farr
26-Jan-2012, 21:23
Hi,

I've been using Pyrocat-HD in BTZS tubes at 75 degrees and quite pleased with it. Since P-M is supposed to have greater acutance was interested in learning about others experience with it.

Thanks in Advance,
Bob

mdm
27-Jan-2012, 01:30
I use home mixed Pyrocat M, most recently as divided developer. Seems fine to me, I wouldnt worry about it. Its cheap, easy to mix up and a little goes a long way.

Ken Lee
27-Jan-2012, 05:53
See the discussion on this forum at this thread (http://www.largeformatphotography.info/forum/showthread.php?t=63210), where the inventor states the following:

Pyrocat M will give very similar results to Pyrocat-MC. It is essentially identical to -MC but is mixed in water instead of glycol and contains sodium metabisulfite which is replaced functionally by ascorbic acid in -MC. Pyrocat M uses the same Stock B solution as -HD and -MC

Compared to Pyrocat-HD you should see a tad more acutance when developed with rotary processing (Jobo, BTZS tubes, etc). Film speed is slightly less than -HD but you probably won't notice the difference.

Another place to search is APUG.

For example, see http://www.apug.org/forums/forum37/27497-new-pyrocat-m-experiences-8.html where the inventor makes the following statement:

From the perspective of sensitometry there is very little difference between the three Pyrocats if measuring with Visual or Blue mode. And that is not by accident since I adjusted the amount of metol and p-aminophenol to give the same energy level as with Pyrocat-HD. However, for UV mode there is an advantage to Pyrocat-MC in that B+F or general stain is somewhat less with long develoment times than with Pyrocat-HD. Also, if you look at the grain structure through a microscope you will see a distinct difference between the three developers, which could matter for persons enlarging 35mm and roll film.

Finally, although my original testing indicated the contrary, a lot of additional testing recently has convinced me that Pyrocat-HD gives the highest EFS with most emulsions (which is just a tad more than D76 1:1 but less than Xtol by about 1/4 of a stop), followed very closely by Pyrocat-MC, with Pyrocat-P showing a loss of about 1/4 stop relative to Pyrocat-HD. However, as I have mentioned before in this thread, small variations i results are to be expected with formulas that we mix ourselves since we often wind up using chemicals from a variety of sources.

mikew
31-Jan-2012, 16:20
After running through all the Pyrocat formulas I actually settled on the para aminophenol formula for divided development in tubes that I fabricated my self (5x7, 8x10, 11x14). The ridges inside the 8x10 BTZS cause uneven staining and do not work so don't even bother trying them. I did notice a very slight increase in accutance with M and P over HD but very very slight. It would only make a major difference if you plan to enlarger the neg 10x. You might see a difference there. Otherwise, the stain is about the same for all but the film speed does differ with M and P relative HD.

Hope that helps.

Mikew

Bob Farr
31-Jan-2012, 17:21
Hi Mikew,

Thanks that is very helpful about the Pyrocat-M. Perhaps not enough of an issue to do the testing.

Have been using the BTZS tubes, 8x10 size, for 5x7 and have not noticed a problem with unevenness in development.

Bob

mikew
5-Feb-2012, 17:28
Hi Bob,

I should have mentioned that the testing that I do is from negatives exposed the old Ansel Adams way with bellows at infinity and the surface being within 1/10 stop luminance. I expose for different Zones and 7 and 8 seem to show any potential development issue. That's how I determine evenness. If you're using a textured surface life a group of trees as your test you'll be fine. Only if you have large expanses of sky or shadow it might cause a problem, but that's with from 8x10 testing.

I didn't use the BTZS tubes for 5x7 because when I saw the results I built my own tubes; and I'm sure that the physics of the developer action in the 8x10 tube and the size of the 5x7 film relative to the tube would offer different results than 8x10 film.

Best of luck.

Mikew

mdm
5-Feb-2012, 18:01
The 2 pictures I put in the safe havens for tiny format thread yesterday were both overdeloped in standing Pyrocat M 1:1:150. I forgot them and they were in the developer 50 minutes. Ok for the top underexposed neg and the normally exposed neg below it but contrasty negs are unscannable in the highlights. So 50 minutes is too long, 36 works fine for FP4 and acros 100. Experience is the best test, you cant really go far wrong.

mikew
6-Feb-2012, 04:08
Having not seen them, I would guess that's also assuming that your subject matter was textured without significant areas of either large expanses of blue sky or shadow...otherwise you'll get mottling for sure. I've tried it....25 different ways or more.


The 2 pictures I put in the safe havens for tiny format thread yesterday were both overdeloped in standing Pyrocat M 1:1:150. I forgot them and they were in the developer 50 minutes. Ok for the top underexposed neg and the normally exposed neg below it but contrasty negs are unscannable in the highlights. So 50 minutes is too long, 36 works fine for FP4 and acros 100. Experience is the best test, you cant really go far wrong.

Jay DeFehr
6-Feb-2012, 06:35
Not related to Pyrocat, but Low Frequency Agitation--the last pic I posted in tiny formats was TMY-2 developed in 510-Pyro 3:500, 70F, 15:00, agitated by inversion 10 seconds/ 5:00. The light was very flat, but development expanded the mid tones quite well, and development is perfectly even. I used the same development for Acros exposed in an old box camera, with similar results. In my experience, stand development with staining developers is a recipe for disappointment, and the very small increase in agitation frequency required to ensure even development does not significantly decrease the effects associated with stand development.

I formulated a developer specifically for stand development (GSD-10), but even so, except for testing, I always agitate at least once during development, and more often at thirds, as above.

mdm
6-Feb-2012, 09:06
I do 3 agitation cycles, 1 every 9 or 10 minutes. In my experience I am more likely to screw it up developing any other way.