Alan, we must try and work on this problem - because I have over £20-worth of Pyrogallol locked up in that 250ml 'A' bottle !
Looking back at the formula, I can see that one of the differences between the WD2D and H , comparing to PMK, is that they use a lot more Sodium Bisulphite : it's 3:1 Pyrogallol to Bisulphite in the WD developers, and 5:1 in PMK. Maybe one of the chemistry experts can comment on what difference that makes ?
Mark, I found in the printing of my neg that it was indeed quite under-developed. Honestly, I hate testing this kind of thing when I already have other developer formulas that I'm satisfied with. I had mixed only a small amount of WD2H so I'm not concerned if I toss it someday. Who knows? I'll leave it sitting on the shelf and, maybe, some day in the future I'll get the itch to experiment further with it.
Good luck and pass on any info you discover.
Fine, I understand ; let's see if anyone else comments. I can do some maths in the near future and work out how to make a larger bottle of 'A' solution that adds more water, Metol and Pyrogallol but no Bisulphite .
I will also ping John W one more time, for comments.
For reference, here is a comparison of the contents of working solutions of WD2D, WD2H and PMK. I've excluded the EDTA-Na4 as it is sometimes there, sometimes not. WD2D originally had different dilution recommendations for roll and sheet film, the sheet film being the more concentrated end of the range.
I have not measured the pH values. Hutchings claimed PMK is 9.6. The Wimberley developers should be somewhat higher, which makes the working solution less stable without more sulfite. More sulfite means less stain (all other things being equal), however note WD2H has less sulfite than WD2D and in fact the sulfite and developing agent concentrations of WD2H are essentially the same as PMK.
I have not tested the Wimberley developers myself but a different stain color than PMK is claimed due to the different alkali and/or alkalinity.
PMK seems to temper highlight contrast somewhat. This would tend to allow for more development which could result in slightly better film speed than other pyrogallol developers. It is possible this could have to do with a reaction between the metaborate and pyrogallol which reduces activity. This reaction between borate and ortho-hydroxybenzenes has been reported in the literature but I don't know if Hutchings knew about it.
Thanks for putting that together Michael.
I went part-way through something similar when I got the first results from WD2H.
I'm not sure I can agree with you that the sulphite-to-developer ratios are essentially the same. I'm still seeing 30 to 35% for the WD developers and 20% for PMK. If as I suspected ( and you confirm) , the sulphite reduces stain, then that seems like the only explanation for what I've seen, which is distinctly less stain on Fomapan 200 with WD2H , even in increased concentration. In fact there is hardly any stain, which make it rather pointless to use !
This goes against what I'd expected from the Wimberley developers, where John had said that the more alkaline 'B' solution with the carbonate would allow the stain to develop more fully, in contrast to PMK.
I think the pH of WD2H ( which I tested during the problems ) is around 9.8 or 9.9
However it looks to me like the extra sulphite ( aka sulfite ) is working against this.
The main reason I wanted to try WD2D+ or WD2H was that the stain is supposed to be more yellow/brown, rather than greenish with PMK, which ought to work better with VC paper.
I suppose i could still try something with less sulphite, like a PMK 'A' , with the carbonate 'B' solution ? Presumably some of the the issue with stability is about using the developer soon enough, which I do anyway ( typically 2mins from mixing to deploy ) ...
Unlike John, I'm not currently doing long development times for N+3 or 4 as John was with the petroglyph photos.
It’s really the concentration of sulfite in the working solution rather than the ratio of sulfite to pyrogallol that affects stain. The difference between 0.2 and 0.3 g/l is small. All other things being equal, a sulfite concentration of 0.3g/l should allow for significant imagewise stain. U haven’t used Wimberley’s developers so I don’t know what the negatives are supposed to look like. Imagewise stain can sometimes be difficult to evaluate visually. I suggest trying to print the negatives and/or taking some densitometer readings through a blue filter (or the blue channel on a colour densitometer) to get an idea of how much density there is.Originally Posted by Mark J
OK. I haven't got a densitometer ( we used to have one at work but it's been retired ) .
I keep thinking about it but find it hard to justifiy approx £1000 for a current one with a blue channel option.
I have negs from WD2H and PMK on the same scene on the same day, I just need to dig out the correct pair ( there was some initial trouble with a suspect mix of carbonate ) .
Hence I can compare , knowing what I'm used to from PMK over the years. Even with a 10% increase on concentration on the A and B , the WD2H negs fell well short of the visual density of the PMK ones.
I will try & take a shot to illustrate if I can get the negs & info together.
It’s interesting you’re saying visually the WD2H negatives are noticeably thinner than the PMK negatives of the same scene. Even if we leave aside the difference in staining, if the silver density is noticeably thinner and contrast is the same I’m puzzled by that, because it would mean a big speed loss from WD2H relative to PMK, which I would have trouble explaining. On the other hand if both the density and contrast are low maybe the development time needs to be extended (which would also increase stain).
OK I should clarify, the Zone 2 detail on the WD2H ones was nearly the same as the PMK ones, so i don't think there's a fundamental loss of speed; they just look under-developed.
Thime for a Proper Proof or two. Never mind how the negatives "look", see how they perform.
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