For those of you who are curious about the real differences between Hypercat and Pyrocat MC, I have some curves that demonstrate their respective characteristics in a very graphic way.
A friend was kind enough to email me some curves Sandy King posted for some of the litter of Pyrocats, and I have a curve for Hypercat that makes for an interesting comparison. King doesn't give information regarding developer dilution, or temperature, but being somewhat familiar with his testing practices, I'll speculate that the dilution
is the standard 1:1:100, the development temp is 72F, and agitation is rotary, probably in BTZS-type tubes.
The Hypercat curve was generated as follows:
Film-FP4+
Developer-Hypercat
dilution- 1:3:200
time- 7:30
temp.- 70F
agitation- Rotary, Jobo
densitometry- blue diffuse
About dilutions and concentrations
While Hypercat and Pyrocat MC are very similar in formulation, it can be confusing to decipher their respective dilutions, because Hypercat is 2X as concentrated as Pyrocat MC, and Hypercat uses a 20% sodium carbonate solution as its B solution, while Pyrocat MC uses a 75% potassium carbonate solution. For clarity of comparison, the developers as tested contain/ liter of working solution:
Pyrocat-MC
catechol .5g
metol .025g
ascorbic acid .04g
potassium carbonate 7.5g
Hypercat
catechol .5g
ascorbic acid .025g
sodium carbonate 3g
The curve for Hypercat was generated during tests for optimum carbonate concentration. All of the tests were developed identically in my Jobo ATL 2 Plus processor, for 7:30/70F, but the carbonate concentration varied from 1:1:200-1:12:200, and it is the carbonate concentration that appears where development time usually does. So, where it says "Curve=3:00", that indicates the dilution was 1:3:200, and not that the film was developed for 3:00 minutes.
similarities
Contrast and SBR are equivalent for a common paper ES, flare density, and speed calculation method.
Differences
Film speed-
For an equivalent normal contrast, Hypercat gives an EFS (Effective Film Speed) of 160-, and Pyrocat-MC gives an EFS of 125+. This is not a big difference, but might surprise some who have read Sandy's claims that Hypercat loses speed compared to the Pyrocats.
Development times-
For normal contrast, an equivalent dilution and development method, Hypercat requires 7:30 min @ 70F, and Pyrocat-MC requires 10:00 min/72F. This might surprise a lot of people, considering Hypercat contains no secondary reducer, and 60% less carbonate than Pyrocat MC.
Stain-
Hypercat produces more image stain than Pyrocat MC. Metol and ascorbic acid both reduce stain formation, and Pyrocat MC contains more than 2X as much combined ascorbate and metol, as the ascorbic acid content of Hypercat.
Fog-
Hypercat produces less fog than Pyrocat MC, probably because it uses less than 1/2 as much alkali as Pyrocat MC. Didn't Haist say something like -"If you have too much fog, you have too much alkali"?
Sharpness-
Hypercat is sharper than Pyrocat MC. Because Hypercat uses no secondary reducer, it tans and stains more efficiently than Pyrocat MC.
Grain-
Hypercat produces finer grain than Pyrocat MC, because it stains more efficiently, works at a lower pH, and contains no metol.
I think Pyrocat MC is a very good developer, but in my experience, and in comparative testing, Hypercat performs better. There are very few single-agent developers, fewer single-agent tanning/staining developers, and none like Hypercat, that are made up in glycol and produce full film speed.
The formula:
Hypercat A
catechol 10g
ascorbic acid .5g
propylene glycol 90ml
Hypercat B
distilled water 750ml
sodium carbonate 200g
distilled water to 1 liter
mixing A
Add the catechol and ascorbic acid to the glycol at room temp, heat to
125-150F with stirring until dissolved. Allow to cool to room temp
before storing in a plastic container. The color of the stock solution
should be clear to very light amber.
To make a liter of 1:3:200 working solution, add 750ml water, 5ml Stock A solution, and 15ml stock B solution to mixing container, and top up with water to 1 liter. Enjoy.
Jay
Bookmarks