A helpful tip
A helpful tip
got some old fogged plates PBU makes a good film defogger
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rzeheb
A helpful tip
Can you spell out what PBU stands for? I've been trying to figure it out (or guess), but I'm coming up empty. Thanks, Ron
A helpful tip
PBU Bleach
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Tom B.
A helpful tip
Can you disclose the recipe for the PBU bleach you used and some idea of the procedure you followed to defog your plates?
A helpful tip
PBU-Amidol Bleach formula: (http://www.holowiki.org/index.php?title ... ing_BLEACH)Tom B. wrote:Can you disclose the recipe for the PBU bleach you used and some idea of the procedure you followed to defog your plates?
Potassium Persulfate 10 grams, Sodium Bisulfate (or Citric Acid) 10 grams, Potassium Bromide 20 grams, Cupric Bromide 1 gram, Amidol (- add last ! -) 1 gram
For PBU-Metol use 1 gr Metol instead of 1gr Amidol.
To use it as defogging solution, PH must be raised first, otherwise the sensitizing dyes will be deactivated, this is true, at least for the PFG-03C dyes .
Read also this (initially posted here: http://holoforum.org/oldforum/viewtopic ... 910#p38628):
"I have some PFG-03C film material, that is more or less fogged,
(some pieces that were in a black paper envelope outside the fridge are totally fogged, D>2)
and have wanted to try Jeff's "Fog Killer Bleach" Solution.
As I do not have the Ferric EDTA salt, I substituted it by mixing equal quantities of Sodium EDTA and Ferric Sulfate.
The result was disappointing: This solution attacked the Slavich dyes, the film got decolored and desensitized.
Although I did not measure the PH of the solution, I am quite sure that it is not in the right range, probably too acid.
I then thought to use my favorite PBU-Metol Bleach instead.
I diluted it 1:10 and measured the PH, that was very acid, about 2.3.
I plunged a piece of PFG-03C film into, that also got decolored.
In order to prevent dyes degradation, I followed Jeff's suggestion (in a previous post ) and raised the PH of the
diluted Bleach (PBU-Metol Bleach, diluted 1:10) by adding some drops 10% Sodium Hydroxide, till the PH raised to 5.6.
In dark, I soaked a piece of film for 1 minute into this solution, then rinsed it and let it dry.
I cut the film in 3 pieces and proceeded as follows:
Piece #1: I turned on the light and observed it. The film has always had it's original color, an indication that the dyes have not been destroyed.
Piece #2: I developed it in dark. The film remained absolutely clear, D=0.
With the film being in the developer, I turned the light on for a few seconds. The film has darkened to D>3.
Piece #3: I made a contact copy @633 nm, with an old red reflection hologram as a master.
The resulting hologram is very bright.
I have not any PFG-03M film or plate to test, but this process should also work fine with this material, it is worth the try.
Since the chemical reaction that takes place in the "fog killing process"
is the oxidation of metallic Silver (Ag) to Ionic Silver (Ar+),
I suppose that many (if not all) rehaloganating bleaching solutions will have the same fog killing effect,
provided the PH is properly adjusted to prevent dyes from damage."
A helpful tip
yep PBU-Metol Bleach is best it dont stain the gelPaulos wrote:PBU-Amidol Bleach formula: (http://www.holowiki.org/index.php?title ... ing_BLEACH)Tom B. wrote:Can you disclose the recipe for the PBU bleach you used and some idea of the procedure you followed to defog your plates?
Potassium Persulfate 10 grams, Sodium Bisulfate (or Citric Acid) 10 grams, Potassium Bromide 20 grams, Cupric Bromide 1 gram, Amidol (- add last ! -) 1 gram
For PBU-Metol use 1 gr Metol instead of 1gr Amidol.
To use it as defogging solution, PH must be raised first, otherwise the sensitizing dyes will be deactivated, this is true, at least for the PFG-03C dyes .
Read also this (initially posted here: http://holoforum.org/oldforum/viewtopic ... 910#p38628):
"I have some PFG-03C film material, that is more or less fogged,
(some pieces that were in a black paper envelope outside the fridge are totally fogged, D>2)
and have wanted to try Jeff's "Fog Killer Bleach" Solution.
As I do not have the Ferric EDTA salt, I substituted it by mixing equal quantities of Sodium EDTA and Ferric Sulfate.
The result was disappointing: This solution attacked the Slavich dyes, the film got decolored and desensitized.
Although I did not measure the PH of the solution, I am quite sure that it is not in the right range, probably too acid.
I then thought to use my favorite PBU-Metol Bleach instead.
I diluted it 1:10 and measured the PH, that was very acid, about 2.3.
I plunged a piece of PFG-03C film into, that also got decolored.
In order to prevent dyes degradation, I followed Jeff's suggestion (in a previous post ) and raised the PH of the
diluted Bleach (PBU-Metol Bleach, diluted 1:10) by adding some drops 10% Sodium Hydroxide, till the PH raised to 5.6.
In dark, I soaked a piece of film for 1 minute into this solution, then rinsed it and let it dry.
I cut the film in 3 pieces and proceeded as follows:
Piece #1: I turned on the light and observed it. The film has always had it's original color, an indication that the dyes have not been destroyed.
Piece #2: I developed it in dark. The film remained absolutely clear, D=0.
With the film being in the developer, I turned the light on for a few seconds. The film has darkened to D>3.
Piece #3: I made a contact copy @633 nm, with an old red reflection hologram as a master.
The resulting hologram is very bright.
I have not any PFG-03M film or plate to test, but this process should also work fine with this material, it is worth the try.
Since the chemical reaction that takes place in the "fog killing process"
is the oxidation of metallic Silver (Ag) to Ionic Silver (Ar+),
I suppose that many (if not all) rehaloganating bleaching solutions will have the same fog killing effect,
provided the PH is properly adjusted to prevent dyes from damage."
A helpful tip
this opens a whole new idea, I'm working on, to backward work film to come up with a holographic film out of Litho film....still in the experimental stage
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Tom B.
A helpful tip
Thanks all - Since I have accumulated a fair stack of expired plates and film, I am always interested in recipes that might resurrect them.