Cor
18-Aug-2011, 06:08
This is more a FYI, although further comments off course appreciated..….
I shoot 4x5 MACO IR (aka EFKE IR) film on a regular basis for years now. I always soup this film in PyrocatHD. And I mostly print on VC paper.
Measuring UV light with a normal light meter is an assumption at best, it’s kinda hard to nail an exactly right exposure on IR film with a non-dedicated UV light meter (which I do not have anyway). My Gossen Luna 6 does a quite decent job. But occasionally I end up with overexposed negatives (quite easy with IR film). Than the pyro stain comes in handy. The heavy stain in the blown out highlights act as a low contrast VC filter, thus lowering these highlights.
But sometimes there is just too much stain, and you’ll end up with a flat, lifeless image. Printing at a higher grade does not help, the stain in the highlights is constant and so is the printing of these highlights, the print gets an even flatter appearance. Perhaps because there is also considerable stain in the mid regions as well.
So such a negative would benefit from the removal of the Pyro stain.
Recently I had such a negative and I treated it with Kodak S6 stain remover, and it worked like a charm. After stain removal I still had a flattish negative, but printing on Grade 3 ½ I obtained a very nice print, with a nice contrast and punch en bright white clouds not that murky light gray.
Perhaps a bit cumbersome but an excellent tool to salvage a lifeless negative,
Enjoy,
Cor
And here the formulae:
Here is the Kodak S6 formula for removing of stain:
Stock solution A:
Potassium parmanganate 5.2g
Cold water to make 1l
The permanganate has to be dissolved completely to avoid spots on the
neg.
Stock solution B:
Cold water 500ml
Sodium chloride 75g
Sulfuric acid, conc. 16ml
Cold water to make 1l
Caution: Never put the water into the acid, it will boil up!
Stock solution C:
Sodium bisulfite,
1% solution, this means 1g for 100ml water
1. Harden the film (2-3min) in a hardener solution like 5-10% glyoxal
2. Wash for 5min
3. Bleach in equal amounts of A and B for 3-4min,
the mix is of short shelf life
4. After bleaching put negative in solution C until
all stain is removed
5. Wash thoroughly
6. redevelop under 100W bulb in a non staining developer of low alkali
like D72 dilution 1:2. D76 does no good because of it´s high sulfite
and low alkali which would dissolve the silver image
And while we are at it:
Kodak's D72 Formula DEKTOL
• 750 ml Water
• 3 g Metol-Elon
• 45 g Sodium Sulfite Anhydrous
• 12 g Hydroquinone
• 80 g Sodium Carbonate 1-Hydrate
• 2 g Potassium Bromide Anhydrous
• Water to make 1 liter
I shoot 4x5 MACO IR (aka EFKE IR) film on a regular basis for years now. I always soup this film in PyrocatHD. And I mostly print on VC paper.
Measuring UV light with a normal light meter is an assumption at best, it’s kinda hard to nail an exactly right exposure on IR film with a non-dedicated UV light meter (which I do not have anyway). My Gossen Luna 6 does a quite decent job. But occasionally I end up with overexposed negatives (quite easy with IR film). Than the pyro stain comes in handy. The heavy stain in the blown out highlights act as a low contrast VC filter, thus lowering these highlights.
But sometimes there is just too much stain, and you’ll end up with a flat, lifeless image. Printing at a higher grade does not help, the stain in the highlights is constant and so is the printing of these highlights, the print gets an even flatter appearance. Perhaps because there is also considerable stain in the mid regions as well.
So such a negative would benefit from the removal of the Pyro stain.
Recently I had such a negative and I treated it with Kodak S6 stain remover, and it worked like a charm. After stain removal I still had a flattish negative, but printing on Grade 3 ½ I obtained a very nice print, with a nice contrast and punch en bright white clouds not that murky light gray.
Perhaps a bit cumbersome but an excellent tool to salvage a lifeless negative,
Enjoy,
Cor
And here the formulae:
Here is the Kodak S6 formula for removing of stain:
Stock solution A:
Potassium parmanganate 5.2g
Cold water to make 1l
The permanganate has to be dissolved completely to avoid spots on the
neg.
Stock solution B:
Cold water 500ml
Sodium chloride 75g
Sulfuric acid, conc. 16ml
Cold water to make 1l
Caution: Never put the water into the acid, it will boil up!
Stock solution C:
Sodium bisulfite,
1% solution, this means 1g for 100ml water
1. Harden the film (2-3min) in a hardener solution like 5-10% glyoxal
2. Wash for 5min
3. Bleach in equal amounts of A and B for 3-4min,
the mix is of short shelf life
4. After bleaching put negative in solution C until
all stain is removed
5. Wash thoroughly
6. redevelop under 100W bulb in a non staining developer of low alkali
like D72 dilution 1:2. D76 does no good because of it´s high sulfite
and low alkali which would dissolve the silver image
And while we are at it:
Kodak's D72 Formula DEKTOL
• 750 ml Water
• 3 g Metol-Elon
• 45 g Sodium Sulfite Anhydrous
• 12 g Hydroquinone
• 80 g Sodium Carbonate 1-Hydrate
• 2 g Potassium Bromide Anhydrous
• Water to make 1 liter