I realize that HC-110 without acid would be a lot more active, but are you sure that even unexposed parts would be totally black? Also, you tried to use HC-110 1:16+acid instead of HC-110 1:64, so you could still run a meaningful comparison between these two. While it is trivial to slow down a developer with acid, you really want to make sure that you don't lose two stops of speed in the process.Fomapan developed in 1:16 HC-110 would turn out black because that dilution is too active for this film. That's why I reduced the activity by adding acid, and 1:16 was required in order to get the recommended minimum 6 mL of developer per roll of film, given the volume of the tank in my processor.
Although I did not try this with HC-110, I have always used baking soda to slow development. It is not drastic like vinegar and seems to allow for great tonality. You will have to experiment, but I would try about 5ml in your 300ml working solution. Try a clip test first: Why waste a full roll? - David Lyga
The curve I posted told me what I needed to know, which is what time of development would give me a reasonable characteristic curve for the new mixture I was interested in evaluating.A curve of Fomapan developed normally for it then would be of use. This curve does not tell me much.
PE
Yes, I think you are right. It might not be totally black, but HC-110 at 1:16 without acid would overdevelop fomapan 100 so severely that it would not be worth doing. As noted in my second-to-most recent post, I did do some HC-110 1:64 comparisons to the new mixture, though it was at a shorter development time. I posted the characteristic curves.I realize that HC-110 without acid would be a lot more active, but are you sure that even unexposed parts would be totally black? Also, you tried to use HC-110 1:16+acid instead of HC-110 1:64, so you could still run a meaningful comparison between these two. While it is trivial to slow down a developer with acid, you really want to make sure that you don't lose two stops of speed in the process.
Yes, the new curves you posted show a great match between 1:16+acid vs. 1:64 with times correctly adjusted, so I guess you found what you were looking for.Yes, I think you are right. It might not be totally black, but HC-110 at 1:16 without acid would overdevelop fomapan 100 so severely that it would not be worth doing. As noted in my second-to-most recent post, I did do some HC-110 1:64 comparisons to the new mixture, though it was at a shorter development time. I posted the characteristic curves.
Yes, the new curves you posted show a great match between 1:16+acid vs. 1:64 with times correctly adjusted, so I guess you found what you were looking for.
A final thing I still don't quite understand is graph 1 vs. graph 3 in your posting. In graph 1 you compare HC-110 1:16+acid with development times at 3 and 4.5 minutes against HC-110 1:64, with no temperature specified in this graph. In graph 3 you developed for 6 minutes at 23.9°C and got somewhat more contrast. Was graph 1 taken at the same temperatures? If 3 3/4 minutes is normal development, then 6 minutes should be a massive push ... am I reading this correctly?
This is, perhaps, the ADVANTAGE of using baking soda. Vinegar is too 'all or nothing' to suit me. I like the buffer idea. - David LygaThe good thing about vinegar is that it has no photographic effect other than lowering pH. Baking soda lowers pH, but also increases buffer strength.
I measure powders with volume, PE. Actually, maybe only ONE mL per 300 mL would be better, as the stuff is powerful!!!! - David LygaDavid, baking soda is a solid. So, what is 5 ml???
PE
The buffering in HC-110 is already provided through the Triethanolamine contained therein - with baking soda you'd add a second unrelated buffer system to the mix.This is, perhaps, the ADVANTAGE of using baking soda. Vinegar is too 'all or nothing' to suit me. I like the buffer idea. - David Lyga
Simply the one bought in a grocery store. The Sav-A Lot chain has a pound package for only 59 cents. That satisfies even the frugal David Lyga. There is something about putting this into developers. I am not a chemist and maybe this is simply fantasy, but it seems to impart a sort of smoothness and consistency to the formula. Maybe the 'buffer' aspect is why, I do not know, but vinegar is far too drastic and unpredictible for me to attempt.David, what kind of baking soda? Crystals, powder, what? Each of these occupies a different volume by weight. This is a very precarious method to measure things.
PE
I haven't tried evaluating other factors, such as grain or sharpness.
Several decades ago scientific researchers investigated all kinds of different developing agents and formulas, and came to the conclusion, that the strongest determining factor regarding the speed/grain/sharpness triangle is speed of development. Allow a developer to work for 10+ minutes and results will likely be better than those of a developer which develops to normal contrast in 5 minutes. Therefore it's quite likely, that Alan's modified HC-110 works better than the original formula. Emulsion speed is comparable according to his charts, therefore we can expect some combination of finer grain and higher sharpness.
Surprisingly, HC110 also contains Catechol, which I assume doesn't differ very much from Hydroquinone in that respect, if at all. I'd really like to know the reason for the inclusion of Catechol in this developer.This may be true, but there are only few developer formulas out there with competing development agents, and HC-110 is not one of them. AFAIK HC-110 uses Dimezone-S and Hydroquinone, these are superadditive but not competing.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?