PMK or Pyrocat HD for enlarging 4x5 negs?

[sanking]

Sandy,

Yes, I got alot of base+fog stain, but I also overcooked them, as you might recall from a previous post a few days earlier. Will overdevelopment add alot of b+f stain?

My goodness yes. Overdevelopment should always be avoided, but overdevelopment plus overexposure with pyro staining developers is worse than the plague. The use of pyro staining developers requires good control of exposure and development or exposure times will be very, very long.


Sandy King

[sanking]

A question, not wanting to start any arguments, about color of stain relating to scanning the film for digital darkroom. Any pro/cons on the different stain colors?

Film developed in both pyrogallol and pyrocatechin based developers scan well. Most of my current printing is with digital negatives from scanned PMK and Pyrocat-HD negatives and I have been very pleased with the results from both types of negatives.

Sandy King

[Steve Wadlington]

Thanks Sandy. I have used HC-110 for years because it is so stable and long lived. I sometimes go a long time between developing. The pyrocat HD in glycol sounds like the ticket.

[Jay DeFehr]

Steve,

if you like HC110, you might consider 510-Pyro. 510-Pyro is a single solution, like HC110, and enjoys a similar shelf life.

Jay

[chilihead]

12 minutes for Tri X !!!! No wonder your base fog is high!!!! That is way, way ,way to long!!! What dilution are you using is also what I would ask !!! Dilution is everything (almost) with Rollo!!! After extensive work and I mean extensive- I have found Rollo is a masterful developer -capable of perfect development - 4x5, 8x10 and - 35mm!!! Perfect stain, low B/F, and absolutley CONSISTENT. Not to mention keeping qualities that are just plain marvelous... Harold Leban (inventor of Rollo) was a genius when he came up with this developer for work with the Jobo!

[Jim Noel]

I use Rollo and Pyrocat HD in addition to trying some other staining developers.

I like both Rollo and PCAt but if I intend to enlarge the negatives I prefer PCat because at similar temperatures, rotation speeds, etc I get far less base stain with it. This enables me to have shorter exposures under the enlarger.

I have not tried Pyrocat M as Sandy suggests, but will do so the next time I mix a batch.

[Jorge Gasteazoro]

The green stain does have a relevant effect on the way VC papers react or "see" the light. This has been a well known fact for many, many years. The color stain might vary slightly with the type of water used, or film, but it is not an easily seen variation or imprtant for that matter.

The main difference is the color of the stain which will give different results. I used to use graded paper and for that staining or non staining developers made no difference and in fact was pretty happy with Tmx RS.

As Sandy posted, I think your problem is not the developer but a reasonable way to figure out your correct exposure/development settings.

[Jay DeFehr]

Jorge,

my point was that pyro and catechol produce the same effect, not that there is no effect. If you're starting with a white light, and using subtractive filters (yellow=minus blue and magenta= minus green), it is simply a matter of how yellow the stain is. The result of the stain is a Yellow Filter Effect, which acts to extend the Exposure Scale of VC printing papers, and reduce print contrast. The YFE can be neutralized with magenta filtration, at which point the negative will print more or less as predicted by Blue channel densitometry. I say more or less, because the proportional nature of image stain warps the paper curve at one end or the other, or both to a lesser extent, depending on filtration. For this reason, stained negatives will never print on VC papers exactly like they print on graded papers, regardless of filtration.

Jay

[Jorge Gasteazoro]

I think you need to be more specific. Of course they can produce the same effect but the filtration would be different, therefore the color of the stain results in a different behavior for the paper. If, as you say, the color of the stain had no effect, then the filtration would be the same for both types of stain. This is an important distinction, specially if you are heading down the road of developer manufacturing, testing and experiment design.

Which reminds me, where do you get the light bands or strips they use for the sensitometers? As you know, they come with blue/green, or just blue or green. I would like to put one that is white (preferably 5500 ºK). Is this what you did with your sensitometer and where did you buy the band?

[Kirk Gittings]

May I say that I really appreciate the civility of this discussion. All of you guys have allot of knowlegde and experience to share. Even when it apears to be contradictory, it is all valid. Like Photoshop, there are numerous ways to achieve a given result, some are better for some outputs than others, some are more or less difficult to achieve, but all are successful to some degree and worth investigating.