Sorry to butt in but I've never used Perceptol and am interested in its "high actance / fine grain" properties. I million years ago when I was processing my own film I used Rodinal and LOVED the acutance but had to put up with the grain.
Does Perceptol possess as much acutance as Rodinal?
Is the grain truly that much finer than Rodinal?
I wasn't thinking of such a high pH. I want to stay below the point where ascorbates alone are active. Ascorbate will still serve to regenerate oxidized Metol at pH = 8.7, at which pH it produces results like those of sulfite. This is the reason it works in place of sulfite in the Pyrocat developers that are dissolved in glycol. Its function there is to allow Phenidone or p-aminophenol or Metol to interact synergistically with the catechol when water is added to the glycol stock as sulfite does in the water stock.Patrick,
The rate of aerobic oxidation of ascorbic acid has maxima at pH 5 and 11.5 (google ascorbic acid oxidation pH lester packer).
If that is true the ascorbate version at pH 14 will probably not be as resistant to oxidation as Rodinal.
However it may show considerable increase in film speed.
Is there a formula to test yet?
Perceptol has a LOT less grain than Rodinal. Well, so do XTol and all other developers. If you want grain try APX 400 in Rodinal and push it to 1600.
Ilford Perceptol alias Kodak Microdol-X is not too bad in terms of acutance, and it becomes pretty good at 1+3. But with most films you lose some speed. And of course it is not as comfortable to use as Rodinal and does not last for centuries.
Ian: I tried T-Max a l-o-n-g time ago and hated the results (muddy and blocked simultaneously) but I never really experimented with it because it was so bad. I'll try sanking's formula. That's with T-Max 100? I'll be shooting 4x10.
Photo Engineer: I don't care about speed... only acutance and grain... in that order.
If you are serious about this, I suggest you use ISO 12 with an ISO 25 film and develop accordingly.
PE
OK, I will take the bait. I want good sharpness and definition of detail without emphasising graininess for my chosen film stock and I am happy to sacrifice some effective film speed if necessary to obtain that. Which developer(s) do you suggest? Xtol, D-76/ID-11, Ilfotec DD or others? This would be for Ilford`s Plus series films and Kodak`s T-Max films please, I am not bothered about the other B&W films available.I should remind you that you can only get 2 out of 3 properties at their peak from any film or developer combination. You have speed, sharpness and grain to consider. Pick two of the above and then pick your developer accordingly.
Kodak has published a chart of this for their developers which has been referred to many times here on APUG. IDK if anyone else does.
PE
I have seen that chart many times, although I am not sure that there is an absolute "Best developer" available, even though there are some particular B&W film and developer combinations that seem to be very well matched for each other.Kodak is the only one that publishes such a chart. Go here:
http://www.kodak.com/global/en/prof...wFilmProcessing/selecting.jhtml?pq-path=14053 and take your pick.
PE
BTW, Ilford provide a similar chart.
There are developers that I know of that can do what XTOL does or even better... I know of modern ones that are better. PE
I could supply potassium p-aminophenolate, but it is so sensitive to oxidation that I would have to ship it in concentrated potassium sulfite solution. Would that be alright?
I looked on Ilford`s site, but I can not find it there now. The publications that I have are rather old, so perhaps they are updating them.Keith;
I provided the URL to Kodak. Would you please supply the Ilford equivalent?
Oh, and I appreciate knowing that Kodak is not the only one to publish that type of chart.
Thanks.
PE
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