Holographs

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Martin

Holographs

Post by Martin »

Thank you for sharing the formulas of the two FMG developers.
I agree it would be better to have simpler formulas. If I had to design a new colloidal developer for PFG-03 I now would base it on metol/ascorbic acid. I assume a developer like Jeff Blyth's HRT developer (now JD-4) very likely might be converted into a nice low noise colloidal developer.HRT (JD-4):
sodium carbonate........... 70 g
sodium hydroxide.............15 g
metol....................................4 g
ascorbic acid....................25 g
water.....................................1 L
Regarding bleaching PFG-03 emulsions I tried to follow Markov (SPIE 3294).
The developer is formed of:A
hydroquionone....................5 g
methylphenidone.............0,2 g
sodium sulfite.................100 g
water....................................1 LB
sodium phosphate.........200 g/LC
potassium thiocyanate....40 g/LWorking solution: 40 ml A + 10 ml B + 10 ml C + 340 ml water.
Development time 8 - 10 min. at 16 - 18°CPFG-03 layers processed in that developer can be bleached in the above mentioned iodine bleach. The results were fairly good, high DE at low noise. The reason why this works is, I believe, because the grains formed are relatively large compared to GP-3 etc.
Sergey Vorobyov

Holographs

Post by Sergey Vorobyov »

If somebody asks to me – what main peculiarity of physical developer – I answer – it can dissolve grains of AgBr and precipitate atoms of Ag to centers of sensitivity (small groups of atoms Ag on defects of crystal of AgBr). It is fine process – some specialists say “diffusive transfer” – when in ONE crystal of AgBr go process of dissolve and simultaneous process of precipitation Ag. As I want look this process!
The first physical developers were other – atoms of Ag come to emulsion, to centers of sensitivity from silver nitrate water solution. It is rich amusement now. Modern physical developer use Ag don’t from solution, but immediate from crystals of AgBr in emulsion.
And how many dissolvents of AgBr?
I know only three: sodium sulfite, sodium thiosulfate and ammonium thiocyanate (maybe, potassium thiocyanate).
Each of them can use for physical developer, but only one work better – it is ammonium thiocyanate.
For example, exist good developer – MM-Collo 1. There are many different components and ammonium thiocyanate too. But only 2g/l. It very small for effective dissolves of AgBr.
I made simple experiment yesterday – increase ammonium thiocyanate to 15 g/l (and remove potassium bromide). The brightness of holograms on PFG-03 enlarged appreciable.
I shell check this result tomorrow and write about it.
Martin

Holographs

Post by Martin »

"The first physical developers were other – atoms of Ag come to emulsion, to centers of
sensitivity from silver nitrate water solution. It is rich amusement now. Modern physical
developer use Ag don’t from solution, but immediate from crystals of AgBr in emulsion."Regarding physical development I wonder if there have ever been attempts on using other
metals for physical development (iron, copper, etc. etc.) in Russia."And how many dissolvents of AgBr?
I know only three: sodium sulfite, sodium thiosulfate and ammonium thiocyanate (maybe,
potassium thiocyanate)."I guess one could add ammonia, allylthiourea and potassium bromide to that list. A special
kind would be the developing agent p-phenylenediamine since it develops and forms
complexes at the same
time.
"For example, exist good developer – MM-Collo 1. There are many different components and
ammonium thiocyanate too. But only 2g/l. It very small for effective dissolves of AgBr.
I made simple experiment yesterday – increase ammonium thiocyanate to 15 g/l (and remove
potassium bromide). The brightness of holograms on PFG-03 enlarged appreciable.
I shell check this result tomorrow and write about it."That's very interesting. Raising the amount of ammonium thiocyanate seems very apropriate.
Particularly because Slavich was reported to have increased silver concentration in their
emulsion since the time I used to test PFG-03 (~~1997/98).
Sergey Vorobyov

Holographs

Post by Sergey Vorobyov »

I wrote about modification of MM Colo 1 in particle "GP-3 or MM Colo 1?"
I make comment of your last message some later - I go to "Slavich" tomorrow and shell try clear up about silver concentration in emulsion PFG-03.
Sergey Vorobyov

Holographs

Post by Sergey Vorobyov »

Open the best book about photo process: T. H. James "The Theory of the Photographic Process" 1977, and you can find near 40 solvents of AgBr! But I mean real solvents, which have effective action in develop. And ammonium thiocyanate is better among of them.
Archimed said many years ago – give me the lever and I put up the Earth. I can say today – give me ammonium thiocyanate and I make physical developer.
You wrote about formula of developer of Markov. I don’t use this developer, but I know – it one of the many variants of physical developer and it can work well, as it consist thiocyanate. We can constitute many different formulas of developer, but all of them will be equal to effect if they will consist thiocyanate. My example of change of MM Collo had confirm it idea.
Who can devise the physical develop without thiocyanate (and silver nitrate water solution) equal to GP-3 (or GP-2)? It my competition – if I look holograms on PFG-03 and the brightness of image will be better than brightness after GP-3, I give premium – holographic portrait in my studio.
The parameters of PFG-03m is next: the quantity of Ag in emulsion – 1,6 g/sq m, the size of grains of AgBr (middle): 12-15 nm. The data about size of metal grains in develop emulsion I don’t found.
Martin

Holographs

Post by Martin »

"Open the best book about photo process: T. H. James "The Theory of the Photographic
Process" 1977,"I would definitely add another "best book": P. Glafkides, Chimie et physique photographiques,
Paris 1967 (English translation: Photographic Chemistry, Vols 1 and 2, trans. K. Hornsby,
London 1958)."Who can devise the physical develop without thiocyanate (and silver nitrate water
solution) equal to GP-3 (or GP-2)? It my competition – if I look holograms on PFG-03 and
the brightness of image will be better than brightness after GP-3, I give premium –
holographic portrait in my studio."Hope to meet you - then - at your studio...
But seriously: maybe you are right - though there might exist a great many options
regarding colloidal developers. Unfortunately, I am not in the position to run any tests.
I do not have any PFG-03 films left - that's to say, apart from a few very aged, stained
brown sheets. And, since I would like to expose both at 532 nm and 633
nm, I am not sure whether to order PFG-03c or Ultimate. PFG-03c seems to have a rather low
sensitivity at 532 nm.
Anyway, regarding colloidal development. I never tried developers based on thiourea. Here
is one that might well be adapted to holographic emulsions:Sodium sulfite.......................18 g2-Chlorohydroquinone...........5 gSodium metaborate............40 g1-Allyl-2-thiourea ..............0.75 gBoric acid............................2.5 gDistilled water.........................1 L
The chlorohydroquinone very likely could be replaced by metol/ascorbic acid, boric acid might be omitted."The parameters of PFG-03m is next: the quantity of Ag in emulsion – 1,6 g/sq m, the size
of grains of AgBr (middle): 12-15 nm. The data about size of metal grains in develop
emulsion I don’t found."Given that the former Agfa emulsions had a silver content around 2,5 g/ sq m, I believe, one might
wonder about the silver concentrations of the Ultimate emulsions (since they are said to
have 8 nm grains at a speed of 200 uJ).
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