Afterbath - sometimes the sheets just go back into the used PMK developer, sometimes into a separate tray of metaborate. Doesn't seem to make much difference.
Just an alkaline environment.
Afterbath - sometimes the sheets just go back into the used PMK developer, sometimes into a separate tray of metaborate. Doesn't seem to make much difference.
Just an alkaline environment.
My understanding was that this second bath just raised FB+F and did not really contribute to usable stain and that GH himself no longer favored this second bath? Not first hand knowledge-just something I vaguely remember from a couple of years ago.
Thanks,
Kirk
at age 73:
"The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep"
Depends, Kirk. GH's more recent tweak of PMK (Pyro Max) and omitting the afterbath
was an attempt to make HP5 more printable on both conventional VC papers and Azo
or other contact processes. It does this as a kind of compromise. (I won't get into this
tweak vs. pyrocat formulas or w2d2+ strategy etc. When I contact I prefer high-end
VC papers anyway, mainly for the way they tone.) With HP5 and FP4 an afterbath can
indeed overdo the stain. But with TMX and tabular grain films, an extended afterbath allows fine-tuning of the highlights, and I don't see any evidence of across-the-board neutral density - it seems selective. In other words, what is true in one set of circumstances does not warrant a generalization with all types of film.
This has been my observation using used developer.Originally Posted by Kirk Gittings
Any staining in a used developer should be non-selective as there is no development occurring at that point, as all the undeveloped silver halide should have been removed at this point.
Kirk - www.keyesphoto.com
Drew,
Every time I've measured stained step wedges that have been treated with an after bath, any increase in stain is in general stain, not proportional stain. In other words, if the stain increases by 0.15 on the dense end of the wedge, it also increases by the same amount on the thin end. This is using the spent developer. A plain alkali bath adds no stain whatsoever over simply soaking in water for the same length of time.
PMK is extremely sensitive to oxidation which leads to chemical fogging ...read high base fog densities and ugly tonality. Some years back I incorporated nitrogen gas into my process, both in a jobo and in inversion tanks. The base fog all but disappeared and the color of the stain on the neg changed from a yellowish green to an amber. The negs print much better too. If the dev. comes out the same color as it went in, you're in good shape. If it's very much darker then it's oxidized.
The alkali after-bath was Hutchings' original suggestion back when he first printed his how-to book on PMK in the late eighties (was it really that long ago?) and of course everyone, including myself, followed suit. While you are increasing the stain on the negative it is a general, overall increase effecting the less dense areas just as much as the areas of greater density. This has the effect of simply increasing your b+ f density effectively flattening out your mid-tones and making it increasingly more difficult to print for black. It's really not at all a surprise that once the mid-nineties rolled around Mr. Hutchings changed his mind on the whole extra-stain/afterbath thing. So some of that stain that you are seeing might be the result of an overall oxidation/chemical fogging which, yeah, I guess makes your highlights brighter.
If you had been paying attention to my diatribe, I already mentioned something which
defintively gives evidence that the stain is not just added overall density due to aerial
oxidation. Namely, I made a tweak to PMK with afterbath included in which there is no
visible silver image - in other words, put the developed HP5 neg over a lightbox and you see almost nothing unless viewing thru a deep blue filter (and printing with one
onto VC or very hard graded paper). The prints have exceptional crisp scale, and were
therefore printed off PROPORTIONAL yellow stain. Whether the current HP5 will act
in the same manner I don't know. And I couldn't get this tweak to work with any other
film. But even with other films like T-grain, you can judge the effect thru a blue filter
respecting microdensity, edge effect, what is and is not proportionately stained.
You're telling me that elephants don't exist when I've got them roaming the darkroom on a routine basis. Maybe you're confusing this kind of stain with fog from aerial oxidation. I'm well aware of what happens with PMK in a rotating drum and don't use one for this kind of developer. My negs tend to have relatively clear margins.
Drew,
PMK definitely produces proportional stain, but the after bath does not. Many have bleached out the silver from stained negatives and printed the stain image. I've done it with many different films. It's more useful for scanning than printing, in my opinion, and even there, the combined silver/stain image is more practical and flexible.
I totally agree with Jay on this. The after bath produces nothing but general (base+fog) stain. Like Jay I have tested this with both Visual, Blue and UV light with numerous films. The general stain contributes nothing to image formation, and nothing to overall density range or CI, but it does add extra density, which will increase printing time slightly.
The only possible positive benefit to the after bath might be a reduction in the appearance of grain.
As others have pointed out, the after bath procedure was recommended in Gordon Hutchings book, but my understanding is that he has since changed his mind and no longer recommends this practice. I have never recommended the after bath with either Pyrocat or with any other pyro staining developer. I am 99.99% convinced that it offers no benefit whatsoever to printing, whether it be VC silver, graded silver or alternative printing, with the possible exception of finer grain, and I am not convinced of even this.
Sandy King
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I'm just not getting that impression of fog in the shadow areas. It seems more like
selenium enhancement on thin-emulsion films (different printing effect, of course, which is the whole point). I was going to ask about bleaching tests, which thank you for anticipating. But my HP5 tweak involved no bleaching whatsoever. Just did some
comparison dev with Bergger 200 w/o afterbath, but haven't printed any of it yet.
I've used PMK with just about every film out there except TriX, and do notice with
respect to this question a real difference between thicker emulsion behaving films
(like HP5 and Super-XX, which base stain relatively easily), and thin fine-grained films which seem to need the afterbath to get good highlt stain and differentiation
from the shadows. I'm obviously a bit skeptical that all the variables have been
successfully covered by the usual suspects. As they say, maybe it's phases of the
moon ...
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