Jay, you're right. It was so long ago that I worked out that formula that I forgot what I'm talking about. The glycol was a solvent for the phenidone.
Jay, you're right. It was so long ago that I worked out that formula that I forgot what I'm talking about. The glycol was a solvent for the phenidone.
Paul,
I'm a little disappointed! On the other hand, my formula for a concentrated glycin developer is concentrated enough, I suppose.
Distilled water: 50ml
Sodium sulfite: 12g
Glycin: 10g
Potassium carbonate: 75g
Distilled water to 100ml
This concentrate is diluted 1:50 for intermittent or rotary processing, and 1:100-1:200 for low frequency agitation development.
The above keeps very well due to the high concentration, and makes a good alternative to Rodinal.
Jarin,
Glycol and TEA are solvents for the developer compounds in the same way water is in standard developers; they are not silver solvents like sulfite. These solvents are not really preservatives in themselves, but allow the formulation of developers with low preservative content by omitting water from the stock solution, so that only the working solution (diluted with water) needs to be preserved, and only for the duration of development. In these developers ascorbic acid plays the role of preservative, and can be used very sparingly compared to typical concentrations of sulfite in standard developers.
I've tested glycin with pyro, and while it works, it doesn't work as well as 510-Pyro, so I didn't pursue it further.
Jay:
Thanks so much for clarifying. I imagine if I am mixing fresh per batch, this would be another way to get away with very low sulfite.
What were the specific advantages of phenidone over glycin with catechin? What is the benefit of catechin with phenidone versus straight catechin? Does glycin usually cause a loss of film speed?
Has anyone ever played with glycin and catechin? Or just pyrogallol and glycin?
Sorry for the deluge of questions! I may just start experimenting soon.
Jarin,
Glycin has a negative impact on stain formation, and catechol is more sensitive to the effect than pyro is. I formulated a catechol, phenidone, ascorbic acid in glycol developer several years ago, and it was a good general purpose staining developer. It worked with rotary processing or tray development or tank/tube development, etc, and produced full film speed. In the end I abandoned the formula not because it didn't work, but because it didn't work better than 510-Pyro, which is simpler, being a single solution developer. When I decided to have another try at formulating a catechol developer, I was determined to make it as simple as possible, so I began my testing with just catechol and sodium carbonate. To my surprise, those two ingredients made a very good developer! Stain and tanning were intense, sharpness and edge effects were pronounced, gradation was excellent, fog was very low, and even film speed was good when used with intermittent agitation. The only way I could improve the developer was by eliminating the general stain that formed when developing to very high contrast, and by improving tray life. The addition of a tiny amount of ascorbic acid accomplished both of those objectives, and the result is the current version of Hypercat. Adding a secondary developer added complexity without a clear benefit. Film speed with rotary processing could be marginally improved by the addition of phenidone, but sharpness suffered and fog increased. Since I already had a general purpose staining developer that works very well with rotary processing (510-Pyro), I decided to keep Hypercat simple and let the catechol go solo, and I've been very pleased with my results. I use Hypercat when I want to sharpen my images, but it produces excellent gradation as well, and very fine grain, even with fast films.
This was made while testing an old Kodak 2A folder with TMY-2 and Hypercat, along with others from the same set. I just don't see any good reason to add a secondary agent to a catechol acutance developer.
try this:Originally Posted by Jarin Blaschke
RD-110 film developer
Part A
Sodium sulfite 12.5g
Glicin 5g
Catechol 5g
Sodium metabisufite 3g
Potassium thiocyanate 1,3g
Water 100ml
Part B
Sodium sulfite 12.5g
Potassium carbonate 33g
Water 100ml
dilute 1+1+50 (pH=9.8). use oneshot. starting dev.time 15-20min 21C. agitation stand or semistand.
Neopan SS 100@100, 20min 21C stand
http://farm8.staticflickr.com/7274/7...e75216_b_d.jpg
http://farm9.staticflickr.com/8003/7...c35174_b_d.jpg
note that this developer isn't stain
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