Pyrocat-HD vs MC Vs. Rollo Pyro / ABC+ for use in Jobo

[Pere Casals]

in my experience, significantly more flexibility is achieved with a PyroCat negative speaking specifically about the Silver Gelatin process.

Steve, I've witnessed your preference for Pyrocat, an this was the main factor in my choice.

IMHO it is with VC paper that we'll see the stain footprint, because stain color has an effect in the contrast and, as the stain is stronger as the densities are higher, then the stain works as a contrast mask that modifies paper grade depending on density in each spot.

I guess that at the end this is equivalent to modified (corrected) toe in the paper curve.

(Paper toe shows the highlights, that are in the film shoulder)

[Fred L]

if you're concerned about the weight of chemistry in the drum, you can just load 4 sheets instead of the 5, or use a different roller base. ( I use Simma bases) and not worry about the weight. Just keep in mind the drum has a tendency to walk off the roller base

[Steve Sherman]

Thanks for responding Pere. I’m aware of the masking technique that Ross suggests as well as other more intricate masking systems. I believe my method of negative design and EMA processing eliminates the need for masking of any type. In my experience any introduction of Green stain or Green exposure with Multi-Contrast papers simply cannot be recovered in lost mid-tone contrast. I regularly pre flash MC papers so that I can reduce the Green exposure which is “projected” through the negative yielding an appreciable gain in mid tone contrast. Pre flashing paper with Green light is significantly different than projection of Green light through the various negative densities. So, starting with a negative producing a stain other than Green seems to negate the need for any sort of masking or other labor intensive and registration dependent techniques. Clearly, the Green stain is counter productive to the Silver printer but does not impact Alt processes using a UV light source. My understanding is that PyroCat may not be as readily available in Europe when compared with PMK and that can be a factor I don’t have to overcome.

[Pere Casals]

My understanding is that PyroCat may not be as readily available in Europe when compared with PMK and that can be a factor I don’t have to overcome.

Steve, there is no problem to mix pyrocat from raw chemicals, also there are at least some 4 ebay sellers (EU based) that make cheap 20L kits, some sell it mixed in bottles.

masking or other labor intensive and registration dependent techniques.

This is not USM, those color masks don't require a precise registration, in the same way that in burning/dodging (split grade) does not require precise boundaries, a mylar diffuser is placed in the middle, and the mask itself may be pretty diffuse.

I made preliminary tests by printing a transparency (mask) having yellow level proportional to the scanned density, it looks it may be really worth sometimes. But (to me) better if no digital mask is there....

Clearly, the Green stain is counter productive to the Silver printer

I try to realize that from the sensitometric effect. The stronger green in the high densities lowers more the contrast in the highlights than in the mids. This tends to compress highlights (with VC papers), this is not necessarily bad if at the end we would burn highlights with the 0 filter in the split grade.

But with EMA you do well that job in the development, of course one of the benefits of EMA is that the highlights are compressed from the local developer exhaustion, so in that case green is not of interest, but anyway it may help perhaps if the negative has high densities in the highlights from a regular development.

With higher stained green in the high densities then the VC paper sports a longer toe, of course paper toe is what shows the highlights (shoulder in the film ). IMHO it all depends on the paper toe extension we want.

What is clear is that the stain revival has a nice interaction with VC papers...

[Steve Sherman]

I believe we’ve gone off the OP original topic so I’ll check out for now

[Pere Casals]

I believe we’ve gone off the OP original topic so I’ll check out for now

Yes, a bit...

Anyway discusing stain color vs VC paper has been really interesting, what's about me I've realized that several factors are involved.

[Tim V]

Thanks again, guys for all of your advise. The discussion around effects of stain colour when printing with VC papers is facinating. Again, I think it's a good time for me to try different developer combinations, having been using PMK only with HP5 / FP4 for quite some time in various formats, although mainly 8x10". THrowing the new process variable of the Jobo CPP-3 in the mix is a bit dangerous, but PMK for rotary it seems. At least, I'm not keen on testing the reliability boundaries for myself, prefering to use something that people describe as 'bullet proof' and still leaves me with the qualities I'm used to, or near enough to it.

So going by all of the experience conveyed above, 1000ml of HD/MC mixed at 1:1:100 is enough to run 5 sheets in a 3005 drum... I guess maybe I'm paranoid because Sandy's instructions say at least 250ml per sheet, but maybe he's erring on the extra safe side? If group concensus is that 1000ml is enough to develop all five sheets in one fill of the drum, so be it. I'll give it a go!

If anyone out there is in fact splitting the development time into two baths, I'd like to hear from you and know how / why.

Thanks again, it's all of great help. I've never used a Jobo before and I already know it's going to be a revelation in more ways than one.

[Tim V]

A new CPP-3 and drums should be on the way to me in the next few days... Just in time, as I have 40+ 8x10" sheets of HP5+ I need to process.

Still a bit nervous about using only 1L of Pyrocat-HD (1:1:100) for 5 sheets... Maybe it's simply safer to process on 4 sheets at a time, that way I'm within Sandy's recommendation of 250ml of chemistry per sheet?

The other option is of course split the development bath into two 1L batches. For those that do this, is it simply a matter of emptying the first bath at the halfway point, refilling with the second bath and completing the development with it? Do you need to add any extra time to compensate for the time it takes to empty / refill, or are there any other tricks I need to be aware of? Potential pitfalls?

Thanks!

[Peter De Smidt]

Just use 4 sheets, until you have time to test. Honestly, if they're really valuable negatives, I would do all testing first.

[agregov]

Just use 4 sheets, until you have time to test. Honestly, if they're really valuable negatives, I would do all testing first.

I agree with Peter. I'm still new to 810 processing in a 3005 drum (CPP3 in my case). Omar at CatLabs also recommended 1000ml max. Talking one day to Rod Klukas (Arca) he suggested 4 sheets with the Expert drums. In my processing so far with PyroCat and C41, I feel my negs were slightly thinner than usual processing 5 sheets at a time. What is interesting is I process 10 4x5 negs in my 3010 with 500ml (2:2:100 or C41) with no issues (= 2.5 810 negs). So, in theory 5 810 negs with 1000ml should perform equally. So, far that hasn’t been my experience. Maybe you don’t get the same amount of agitation in a 3005 versus 3010? Also worth noting, I can see the motor straining some on my processor, even with the latest CPP3 motor. For longevity, it would probably be better to go with less chemistry. I am likely going to move to 4 sheets and see how that goes.

One related story, I took a workshop with Michael Smith several years ago and he scoffed at using a Jobo for 810 negs. He would process up to 14 810 negs at once in a 11x14 tray. He said he came back from trips with hundreds of negatives and processing in a Jobo would take forever. So there is still something to tray processing.