Pyrocat MC/TMAX 400 Test Results

[Tom Hoskinson]

Saturday I processed a 35mm roll of TMAX 400 TMY in Pyrocat MC (1+1+100). I Developed Semi-Stand for 18 min @ 21°C. The acutance is high (African Violets, petal detail, stamens, pistils, cilia, etc.)! Microcontrast is excellent. The fog level is very low. The image stain looks great as well. The densitometry results are here:

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Equipment Used: 35mm Bessaflex/Zeiss 50mm
Densitometric Exposures: 13 separate exposures, 1 f-stop apart (North facing wall uniformly lit by sky light).
Film & Developer: TMAX400 - Pyrocat MC
Densitometer: Macbeth Color Densitometer

If you would like a copy of the Microsoft Excel file, PM me and include an email address.

By the way, my "A" concentrate is light yellow in color. When I mixed the working developer, its color was a very pale yellow color (almost clear). After sitting (and oxidizing) for about 20 minutes, the unused excess of the working developer solution (about 30-40ml) had turned a pale lavender color.

After developing the film the developer was a darker blue/lavender color.

BTW, (I'm using Potassium Carbonate in the "B" solution).

Pyrocat MC is a winner, and it's fast and easy to mix.

Kudos to Pat Gainer and Sandy King!

Pyrocat MC uses Metol, Ascorbic Acid (vitamin C), Triethanolamine & water to form a mixture of Metol Base, and Ascorbate that is soluble in Propylene Glycol.

The Pyrocat MC formula is here:
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[sanking]

Saturday I processed a 35mm roll of TMAX 400 TMY in Pyrocat MC (1+1+100). I Developed Semi-Stand for 18 min @ 21°C. The acutance is high (African Violets, petal detail, stamens, pistils, cilia, etc.)! Microcontrast is excellent. The fog level is very low. The image stain looks great as well. The densitometry results are here:

By the way, my "A" concentrate is light yellow in color. When I mixed the working developer, its color was a very pale yellow color (almost clear). After sitting (and oxidizing) for about 20 minutes, the unused excess of the working developer solution (about 30-40ml) had turned a pale lavender color.

Tom,

I am glad to hear that B+F is very low with TMAX-400 as I will be using a lot of it in the near future, having invested heavily in the TMAX-400 run.

Curious, though, about the color of the mixed working formula. In the solution I used, which was mixed by Pat, the color has been a consistent amber, slighly darker than what I get with Pyrocat-HD. Wonder what could account for the lavender color.

Sandy

 

[Tom Hoskinson]

I don't know, Sandy. It might be due to a trace contaminant in the Potassium Carbonate (Baker Reagent Grade) I used in the "B" solution. I'll try some Sodium Carbonate and see what that does. In spite of the weird color of the spent developer, it worked very well indeed!

The (Kodak) Metol was from my big jar that I've had for many years. The Vitamin C was Trader Joe's pure Ascorbic Acid. The TEA and Propylene Glycol were from The Chemistry Store.

The mixing water was 18 megaohm (Semiconductor Grade - continuously monitored) Deionized water.

Another thought - I mixed the MC stock solution with the same TFE coated stirring bar that I used to mix the Pyrocat P stock solution (I washed the stirring bar afterwards - but???).

 

[Tom Hoskinson]

Sandy, my (just mixed and unused) working solution MC developer was a pale yellow color. The spent working developer eventually oxidized to a lavender color.

 

[gainer]

Colors of organic compounds are often deceiving. Some turn color drastically, like Rodinal, with no noticable loss of activity. Others are still clear after they lose it completely. It is a good thing to leave a thin layer of stock developer exposed until it turns pretty dark and see how much water it takes to make it look fairly clear. This may give you an idea of how small an amount of oxidized developer it takes to make the pot look bad. You can take this diluted tar and see if it will still blacken film. There are some surprises to be had this way. TEA will darken with excess heating, and without any oxidizing agent in it, but according to DOW it is still TEA.