Well.. you also asked me "do you think the alkali stop bath works better than a water stop for staining developed". Isn't that a question best answered by someone who has had the opportunity to use both stops extensively and compared the results? John Finch (or Peter Hogan) could be that guy.I was simply asking your views on whether the £23 bottle of alkali stop bath at 38 pence a roll would be a worthwhile purchase for you. I will take it that you do not wish to answer
That would be a very creative reading of Henry as his results show something rather different in terms of the relationship between sharpness and sufficient agitation for even density (and which agrees with the publication record).
While zero agitation will increase sharpness, it comes at a cost of extremely uneven development - once sufficient agitation is given for even development, the differences between almost all agitation methods/ intervals declines to well within the margin of error. If agitation really had meaningful effects on sharpness once over the threshold for even development, Kodak, Ilford etc would be recommending it at every turn (unlike someone like Sandy King or Barry Thornton - or for that matter Geoffrey Crawley - their analytical wherewithal is much more considerable and statistically significant - and done in concert with double blind visual/ perceptual testing) - instead, they found that it is much better to design emulsions that will react with the developer (in particular developer solvency) to deliver heightened sharpness while allowing for sufficient agitation to deliver very even development (this is really, really important when dealing with colour/ colour separations and getting even grey scales).
That 'bromide drag' you describe is essentially macro scale effects of development inhibiting agents being released from the emulsion(s) - in other words, the stuff that under adequate agitation conditions actually enhances sharpness.
I don't think Kodak and Ilford make Glycin and also Catechol based developers like FX-2 and Pyrocat /Prescysol so it is hardly surprising that they have no recommendations for them. Those that have formulated them do however suggest that reduced agitation provides increased sharpness,which conclusion is supported by some of the users on Photrio.
Gentlemen and Ladies (because who can say for sure with screen names),
We have received at least one suggestion that, as this thread has wandered significantly from anything related to the thread title, shouldn't most of the wanderings be in a different thread all their own.
Would anyone like to start that separate thread? We could put complementary links in both threads.
If there is a clear demarcation somewhere, we could probably start that thread with an edited version of an existing post here, and move everything after that there.
I don't think Kodak and Ilford make Glycin and also Catechol based developers like FX-2 and Pyrocat /Prescysol
have you done tests to compare extreme minimal agitation with Kodak/Ilford recommended agitation? and in your experience have you found that there are no meaningful effects on sharpness?
....
Catechol has intermittently appeared in HC-110 as well - and Glycin in various uses by Ilford, Kodak, Agfa, M&B etc, etc, etc - but there seems to be a point somewhere 1955-70 where the industry collectively catches on to HQMS (and the commercial sensitivity of this knowledge - hence the rather piecemeal and haphazard disclosure of it over the years) and increasingly moves its attention away from the needlessly exotic to a far more remarkable, useful and commonplace (at least in terms of in-situ formation) component instead.
Kodak Alaris current MSDS for HC-110 shows Catechol as an ingredient (under an alternative name, 1,2-Benzenediol)
But it is present in too little a weight percent (0.1 - < 1) to play a role as a significant developing agent once the concentrate is diluted into working solution. It was suggested, IIRC, by @Pixophrenic in a previous discussion on this subject that Catechol plays the role of a preservative in HC-110.
Lachlan, you say that old observations (I presume referring to effect of reduced agitation) began to disintegrate when subject to the level of analytical wherewithal that major research labs had.
Why is this not mentioned in The Theory of The Photographic Process, Mees and James, or in Photographic Processing Chemistry, LFA Mason?
Can you cite one paper to support your claim?
When Haist and Mason wrote their books stand development was largely a newspaper darkroom technique for push processing underexposed films.
Mason does state that care must be taken with High Acutance Developers and agitation, too much nullifying the effects of localised exhaustion, too little reducing the gamma. The instruction sheet for Hyfin warned about excessive agitation, I can't find that sheet at the moment, but the recommended agitation was less than with other developers.
Anyhow, my thread "Scans retain developer properties" does suggest that Pyrocat HD might have an edge.
Sorry I cannot link to it directly.
....... various amateur-hour individuals who are rehashing stuff that was questionable with primitive emulsions and pointless with highly controlled and intentionally engineered ones......
It's just possible that Lachlan is not impressed by by amateur tests and since since all the tests on Pyro and Pyrocat have been done by amateurs they have no chance.
Funny that I have better results by not following the manufacturers' instructions (exposure and development times).
All that I saw was results that could be achieved, equalled or bettered by more direct process control means (i.e. a reduction in process time) to match density - if there was sufficient agitation to get even development.
A bit of anecdata here: I've found that full strength ID-11 seems to actually make noticeably seemingly visually sharper 4x5 negs (i.e. low frequency sharpness effects) with current issue Ilford materials - probably because of the stronger level of developer access to the emulsions releasing more of iodide placed for exactly that purpose.
The SPSE handbook (which is published about the time that C-41 and E-6 are deep in R&D - and thus highly commercially sensitive) discusses agitation and sharpness effects in considerable detail, making the point that evenness of development negates the highest sharpness effects that can be achieved through zero agitation (there's even MTFs of 1+10 DK-50 used without agitation).
Thank you.
Was hoping to find a discussion on minimal agitation techniques and/or diluted staining developers in the SPSE handbook but all I could find was the following:
Section 17.5.2 page 956: "developing with a dilute developer without agitation accentuates the [adjacency] effect."
Section 9.5.2: "development should therefore be under relatively still conditions, because agitation minimizes the [adjacency] effect."
Further, "adjacency effects disappear at full development, but normally one does not develop fully."
And "the same factors that promote adjacency and interimage effects often make uniform processing over the area of the film more difficult."
None of this is new information to many here.
Was hoping to find a discussion on minimal agitation techniques and/or diluted staining developers
There are all kinds of developers out there. When someone claims the developer he champions has magical properties, ask to see his prints.
the various staining developers that have more-or-less-usable function aren't any sharper than something like dilute Perceptol (PQ can potentially go sharper than that) with worse granularity overall.
merely stain your film without adding anything that process controls and Beutler (or Ilfosol 3) can already do or better.
If I understood the discussion on FX-1 and Pyrocat-HD here, it was not claimed that Pyrocat-HD is much sharper than FX-1 or Beutler:
"In a metol developer it is hard to beat FX-1 for absolute sharpness. Beutler should come close. FX-2 is almost as sharp and provides nicer tonal renditions."
"For a pyro type developer PMK, Pyrocat-HD and WD2D+ give excellent sharpness with good tonal rendition and much finer grain (from grain masking by the stain) than Rodianl or FX-1."
I think the claim made, implicitly, was that for an acutance developer, Pyrocat-HD gives a good balance of tonality, fine grain and acutance. Isn't this what long terms users of Pyrocat-HD have also been saying based on their experience?
If dilute Perceptol gives the same or better balance of tonality, fine grain and acutance than Pyrocat-HD, then it is definitely worth considering. What is the dilution you recommend?
Probably the sulphite is required to dissolve Glycin, I have read somewhere in this regard.Well this is supposed to be DiXactol Ultra
DiXactol Ultra (type) Developer
Stock Solution A
Sodium Sulphite 3 g
Glycin 2 g
Pyrocatechin 10 g
Phenidone 0.2 g
Sodium Metabisulphite 5 g
Water to 100 ml
Stock Solution B
Sodium Hydroxide 10 g
Distilled water to make 100 ml
To make a standard working solution, mix 1 part A with 1 part B with 100 parts water.
Develop: 6 mins @ 20ºC
So Part A is acidic like Pyrocat, change Part B to Potassium Carbonate and who knows what it's called . . . . . . . .
The Sodium Sulphite in Part A is completely unnecessary, the Metabisulphite forms Sulphite in an Alkali solution once mixed
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