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At our recent GEH workshop, someone passed out a table containing formulas for 5 grades of Brovira paper which were taken from Glafkides. I tried looking at Glafkides, but there is not a copy to be had locally as far as I can determine. I looked in Duffin, and he quotes Glafkides on two formulas and states that all of the data in Glafkides and also Duffin regarding emulsion formulas in that chapter come from the FIAT and BIOS reports on Agfa and other German manufacturers at the end of the war.
Well, someone helped me out and I read all of these formulas in the original FIAT and BIOS reports and have made some interesting findings.
1. Step #9, reported in the table I have, is wrong. One entire ingredient is omitted, and the values for the others quantities are offset downwards by one therefore making this entire portion incorrect.
2. The original formulas specify the exact type of gelatin at each step, ie. Hard, Medium, Weak and etc, referring to the amount of Sulfur ripening provided by the gelatin. This would have to translate into a modern Sulfur sensitizing step if one were to make any of them today.
3. Times of addition are specified in most cases, but the table purportedly from Glafkides omits it all.
And, most stunning, in the original reports, the English interpreter runs the German SZ together turning it into a B in English, and creates 2 words. Now, either way this can be still read properly but it depends on whether you are a cook or a chemist.
In cooking, it translates as "to begin cooking dump over" or "baste with sauce" but to an emulsion maker it means "to make a coating use this to prepare properly". It implies dump into or coat over though. This may be critical.
Since there are 7 ingredients, including gelatin which was omitted in the table, it is vague as to whether these are finals to be added before coating or to be coated as an overcoat. Since a group of "finals" are added earlier in the formula, this could be an overcoat, but I doubt it. I have discussed this with a native German speaker who is an emulsion maker, and he too is in doubts, but we both feel it could go either way. We lean towards additional finals but without proof.
I peeked at other Brovira formulas (there are 10 in all) and Portriga as well. These latter contain sensitizing dyes and stabilizers to protect the paper during keeping.
This is to let experimenters who have the Glafkides table know that there are errors, omissions and uncertainties. I hope to gather all of it together and post more information on part #9 which pretty much renders the tables useless.
PE
Well, someone helped me out and I read all of these formulas in the original FIAT and BIOS reports and have made some interesting findings.
1. Step #9, reported in the table I have, is wrong. One entire ingredient is omitted, and the values for the others quantities are offset downwards by one therefore making this entire portion incorrect.
2. The original formulas specify the exact type of gelatin at each step, ie. Hard, Medium, Weak and etc, referring to the amount of Sulfur ripening provided by the gelatin. This would have to translate into a modern Sulfur sensitizing step if one were to make any of them today.
3. Times of addition are specified in most cases, but the table purportedly from Glafkides omits it all.
And, most stunning, in the original reports, the English interpreter runs the German SZ together turning it into a B in English, and creates 2 words. Now, either way this can be still read properly but it depends on whether you are a cook or a chemist.
In cooking, it translates as "to begin cooking dump over" or "baste with sauce" but to an emulsion maker it means "to make a coating use this to prepare properly". It implies dump into or coat over though. This may be critical.
Since there are 7 ingredients, including gelatin which was omitted in the table, it is vague as to whether these are finals to be added before coating or to be coated as an overcoat. Since a group of "finals" are added earlier in the formula, this could be an overcoat, but I doubt it. I have discussed this with a native German speaker who is an emulsion maker, and he too is in doubts, but we both feel it could go either way. We lean towards additional finals but without proof.
I peeked at other Brovira formulas (there are 10 in all) and Portriga as well. These latter contain sensitizing dyes and stabilizers to protect the paper during keeping.
This is to let experimenters who have the Glafkides table know that there are errors, omissions and uncertainties. I hope to gather all of it together and post more information on part #9 which pretty much renders the tables useless.
PE