Originally Posted by
Mark J
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.
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