Dev question Pyrocat,Rodinal,Dixactol,etc

[patrickjames]

Now that I have your attention I am an old user of Rodinal in smaller formats and PMK for larger formats. I am looking to get a compensating developer that has the highest acutance possible. I do not really care about grain size as long as it is sharp. I have read good things about Pyrocat HD and thought I read something about a paramenophenol version of this, which might be ideal, but I don't have that info any more. Dixactol looks promising as well. Can anyone fill me in on which dev. might be ideal for this? Remember the most important thing is highest acutance. Did I say highest acutance? I just wanted to make sure that I mentioned highest acutance. Thanks for the help

 

[Tom Hoskinson]

My tests show that Pyrocat MC (with Metol and Ascorbic Acid) gives very high acutance. It also works very well as a Stand Developer.

Do an APUG search on Pyrocat MC.

 

[patrickjames]

Does Pyrocat MC give higher acutance than Pyrocat-P?

 

[sanking]

Does Pyrocat MC give higher acutance than Pyrocat-P?

With the same type of agitation I think it would be very hard to see any differnce in acutance between Pyrocat-MC and Pyrocat-P.

In the class of acutance developers dilution and type of agitation play a very important role in determining acutance. Acutance fundamentally depnds on edge, or adjacency, effects, and this phenomenon is maximized by local developer exhaustion that results from high dilution working solutions in combination with minimal type agitation procedures. All of the Pyrocat developers, and most other acutance developers, give higer acutance and apparent sharpness with reduced agitation than with constant agitation.


Sandy King

 

[Oldtimer Jay]

Hi,

I have not used it in years, but Cawleys FX1, whose formula is in the Film Developing Cookbook, was by far the highest acutance developer I have ever used. To pique your interest, I actually quit using it because it tended to render negatives which printed much like an oversharpened digital print! Perhaps if you experiment with agititation you could tame its excessive adjacency effects. Just a thought...

Good Luck,

Jay L.

 

[Alan Johnson]

I don't think anyone has actually measured it,but if all films were to be developed in the same acutance developer and the acutance scientifically measured,the tabular grain films Delta 100 , T-max 100 and Fuji Acros would likely come out with highest acutance.But IMO these films show least difference between solvent and acutance developers.
If you refer to traditional films,I believe Willi Beutler designed Neofin Blue developer (similar to the Beutler developer) to work with the early versions of the Efke/Adox 25 and 50 films and this combination has to be a contender for highest acutance.FX-1 was Crawley's modification of it.

 

[Tom Hoskinson]

I don't think anyone has actually measured it,but if all films were to be developed in the same acutance developer and the acutance scientifically measured,the tabular grain films Delta 100 , T-max 100 and Fuji Acros would likely come out with highest acutance...

Kodak has done this testing for their films and have published their results(and no doubt other manufacturers have done this sort of testing as well). According to Kodak, TMax 100 is a high resolution, extremely fine grain Tabular grain film. Kodak Tech Pan is even higher resolution and finer grained than TMax 100.

 

[Alan Johnson]

Just to be clear, for the scientific measurement of acutance I meant the making of knife-edge exposures and their analysis with a microdensitometer as described by R.Henry in his book Controls in Black and White Photography.
I don't think any standardized method is likely to be in use,and never saw any results of this type on the net.
For practical purposes I believe higher acutance=looks sharper on the print is the usual usage.

 

[Tom Hoskinson]

Just to be clear, for the scientific measurement of acutance I meant the making of knife-edge exposures and their analysis with a microdensitometer as described by R.Henry in his book Controls in Black and White Photography.
I don't think any standardized method is likely to be in use,and never saw any results of this type on the net.
For practical purposes I believe higher acutance=looks sharper on the print is the usual usage.

I understood what you meant, Alan. Summaries of Kodak's microdensitometry results for their B&W and Color films (RMS granularity measurements and resolution/acutance) can be found in the Tech Pubs on the Kodak website.

I believe that when you talk about acutance you refer to image edge enhancement effects - Mackie Lines, etc. As Sandy King indicated earlier in this thread, these are not inherent properties of the film but are created by the interaction of the film with the developer chemistry and the agitation technique.

 

[Alan Johnson]

Yes, Tom. R.Henry wrote "Since it is admitted that the sense of sharpness depends not only on acutance (here he uses his narrow scientific definition) but also on adjacency effects, either the formula for acutance should be changed ...to include the edge effects or a new term should be introduced to include both"
"This would not be easy to do.." He said in 1986.What happened is that the word acutance seems to have come to include both.

 

[patrickjames]

I am really concerned with the sharpest grain and not really concerned about adjacency effects. I have used FX-1 in the past but I am looking for a developer that has stain as well.

 

[Tom Hoskinson]

I am really concerned with the sharpest grain and not really concerned about adjacency effects. I have used FX-1 in the past but I am looking for a developer that has stain as well.

I reccomend Pyrocat, used with continuous agitation or with minimal agitation, Pyrocat gives excellent proportional image stain and high resolution. When used as a Stand Developer, Pyrocat will also give adjacency effects.

 

[patrickjames]

I think I am going to go with Pyrocat-P since I am used to p-aminophenal already. It seems like it may provide what I am looking for. I want to mix it in glycol so it will last a long time. Any recommendations?

 

[gainer]

P-aminophenol and catechol are superadditive in the presence of some sulfite. The sulfite is not particularly soluble in glycol. I think the formula for Pyrocat P in glycol includes a little ascorbate formed with ascorbic acid and triethanolamine. It seems that the p-aminophenol and ascorbate combination is superadditive without sulfite and acts as a "trigger" for superadditivity between catechol and p-aminophenol. Now all the ingredients of the A solution are soluble in propylene glycol.

I think Pyrocat PC is available from P. F. as a kit or ready mixed in glycol.

 

[sanking]

Quote:
Originally Posted by gainer
"P-aminophenol and catechol are superadditive in the presence of some sulfite. The sulfite is not particularly soluble in glycol. I think the formula for Pyrocat P in glycol includes a little ascorbate formed with ascorbic acid and triethanolamine. It seems that the p-aminophenol and ascorbate combination is superadditive without sulfite and acts as a "trigger" for superadditivity between catechol and p-aminophenol. Now all the ingredients of the A solution are soluble in propylene glycol.I think Pyrocat PC is available from P. F. as a kit or ready mixed in glycol."


Only Pyrocat-HD and Pyrocat-MC are available from P.F. as pre-mixed kit in glycol. For Pyrocat-P you will have to mix your own. But it is very to mix as do as p-aminophenol is very soluble in warm glycol. The formula for 1 liter of Pyrocat-P Stock A in water iis as follows.

Pyrocat-P
Stock A
Distilled Water at 120ºF 750ml
Sodium Metabisulfite 10.0g
p-Aminophenol 5.0g
Pyrocatechin 50g

If you want to mix in glycol, just substitute glycol for the water. Then, mix 10.0 grams fo sodium metabisulfite in 50 ml of very hot water, and stir until completely dissolved. Add this solution to the warm glycol. Now add the p-aminophenol directly to the warm glycol and stir until dissolved. Then add the pyrocatechin and stir until dissolved. The resulting stock solution will be very long lived.

For Pyrocat-PC, you substitute 4 g of ascorbic acid for the 10.0 g of sodium metabisulfite, and add it directely to the warm glycol. Everything else is the same. I have not personally used Pyrocat-PC so can not comment on its characteristics, but I would anticipate that the results would be very similr to Pyrocat-P. However, since all of the chemicals dissolve readily in glycol there should be no need to use the "slutty" slurry with TEA we use to mix Pyrocat-MC. Though if you have the hydrochloride form of p-aminophenol I guess the slurry approach would be the way to go.

Sandy King

 

[patrickjames]

Where can I get the propylene glycol? PF has it in 100ml quantities but I am looking to mix up at least 1 liter if not 2. That would mean $70 per liter which seems quite expensive to me. Does anyone have any suggestions?

 

[Tom Hoskinson]

Where can I get the propylene glycol? PF has it in 100ml quantities but I am looking to mix up at least 1 liter if not 2. That would mean $70 per liter which seems quite expensive to me. Does anyone have any suggestions?

I buy mine from The Chemistry Store http://www.chemistrystore.com/propylene_glycol.htm

$10.00 per quart, $17.38 per gallon

 

[patrickjames]

Perfect Tom, that is exactly what I was looking for.

 

[patrickjames]

I know there are (at least) two formulae for part B of Pyrocat. Which one would be the best for this developer? Would there be any difference?

 

[sanking]

I know there are (at least) two formulae for part B of Pyrocat. Which one would be the best for this developer? Would there be any difference?

The only formula I have personally recommended is a 75% potassium carbonate solution, which is mixed by adding 750 grams of potassium carbonate in water to make 1000ml of Stock B. From this you get the 1:1:100 or 2:2:100 dilution. You could also use a 20% sodium carbonate solution, and mix the working 1:5:100 or 2:10:100. These are not exact equivalents but are close enough to give virtually identical results with potassium carbonate. So basically, the two carbonates are interchangeable

Other people have substituted potassium and sodium hydroxide, or even TSP, and they all work if balanced correctly, but the image characteristics are not the same as with the carbonates.

Sandy King

 

[fhovie]

Pyrocat-p at 1:1:150 with a one hour development time and aggitation every 15 minutes will create accutance that is unnatural and distracting. It is not just the developer, it is how you use it. P'cat at 2:2:100 will drop the film speed and increase the contrast - with normal or less than normal accutance with normal aggitation. You can have too much or too little accutance and neither will make a stunning print. For high definition, I like the semistand method for about 30 minutes with 4 aggitations. It makes a sharp contrasty negative that will not have over-exaggerated mackie lines.

 

[sanking]

Pyrocat-p at 1:1:150 with a one hour development time and aggitation every 15 minutes will create accutance that is unnatural and distracting. It is not just the developer, it is how you use it. P'cat at 2:2:100 will drop the film speed and increase the contrast - with normal or less than normal accutance with normal aggitation. You can have too much or too little accutance and neither will make a stunning print. For high definition, I like the semistand method for about 30 minutes with 4 aggitations. It makes a sharp contrasty negative that will not have over-exaggerated mackie lines.

Some really good points in this post.

Sandy King

 

[patrickjames]

Is potassium carbonate anhydrous the same stuff? Sorry if this is a stupid question, but a chemist I am not.

 

[sanking]

Is potassium carbonate anhydrous the same stuff? Sorry if this is a stupid question, but a chemist I am not.

The Pyrocat-HD formula is based on the use of potassium carbonate monohydrate. If you have the anhydrous form of potassium carbonte, divide the monohydrate amount by 1.17 to get the adjusted amount for the PCAT formula. Same would apply to sodium carbonate.

Best,

Sandy