When I went to put in an order for pyro, the cheapest shipping from Bostick & Sullivan was about half the cost of the chemicals. Are there any other sources for Rollo Pyro other than B&S?
When I went to put in an order for pyro, the cheapest shipping from Bostick & Sullivan was about half the cost of the chemicals. Are there any other sources for Rollo Pyro other than B&S?
The process you are describing is simply two-bath development (process to exhaustion). The point is, it gives a different negative then single solution development. Perhaps the most important difference from a tone reproduction perspective is that it tends to "straighten" the characteristic curve. It also tends to give good film speed with a lower-than-normal contrast negative. This linear curve is something King liked for negatives destined for scanning (he wrote some articles in View Camera about that) because it would seem desirable to start off with as linear a scale as possible, which is then manipulated with software.
You don't have much to lose by trying things, so I suggest you try it a few different ways (including the one in your original post) and decide what you like and what you don't. However as I said earlier, a post-fix soak in solution A should do nothing as it is not alkaline. You can try it, but I'd suggest then doing a second test with the post-fix soak in solution B or C and comparing the results. Perhaps the instruction to soak in solution A was a typo in whatever you were reading.
As a chemist, just a reminder to all that pyrogallol is a very toxic substance readily absorbed through the skin. The LDLo (lowest lethal dose) is 25 mg per kilogram of body weight. Always use a face shield or goggles, a dust mask (necessary for the solid) and nitrile gloves when working with it or its solutions. It is also a cumulative poison in that repeated exposure over time increases the risk. It attacks the liver and the kidneys and in addition red blood cells. While also toxic catechol is a safer alternative for a staining developer. All in all pyrogallol is very nasty stuff.
Which is why Per gave me a box of nitrile gloves during the class.
Excellent. I always worry that someone will read a thread and rush out to try pyro and not know the proper safety precautions. I would rather repeat myself than have some one become sick or worse.
Per Sandy King Pyrocat-HD is better than Rollo Pyro for Jobo processors.
Per Volquartz recommended that Rollo Pyro be used to develop to chemical extinction and ignore the temperatures in tanks or Jobo processors.Presoak
5 minutes solution A
6 to 7 ½ minutes solution B
Two 30 second water rinses for stop bath
TF-4 or TF-5 for 3 minutes at 1:3
Two 30 second water rinses
2 minute solution A for staining
15 to 20 minute wash
Both recommend using the slowest speed for Jobo processors.
My questionS:Will Per Volquartz's method work with Pyrocat-HD in a Jobo processor?
Using the 3010 Expert Drum the minimum amount of chemicals is 210ml, therefore I should use 300ml for six 4'x5" sheets and 50ml f0r 10 4'x5" sheets minimum. To be safe should I be using 400ml and 600ml respectively or more?
As long as you're using split development, it should work with Pyrocat.
I thought this thread was about Pyrocat HD. It uses pyrocatechin as the reducing agent. Who said anything about pyrogallol?
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