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.
Well yes, in that table, there is a big goof.
But I don't see that nor even the total of all the omissions and goofs as a disaster.
The ingredients he goofed up on are not particulary crucial players in the overall picture.
They appear to me as final additions not a supercoat.
Good to know, but not really all that important.
I have all known versions and one or two that were never published - but other than out of curiosity, I never felt the desire to "copy" them. (Out of the question anyway)
I am much more interested in your emulsions! ;)
They are The Real Mystery IMHO!
Ok Ray, then make 5 contrast grades of Brovira from that formula if it is so obvious.
Sorry, but the actual corrections are obscure!
Originally Posted by Ray Rogers
Please share these deep dark mysterious Brovia 'goofed up' ingredients. It would help those of us who Would like to replicate Brovira
The second part is somewhat too vague to respond to...:confused:
Is the first part rhetorical? :wizard:
If I understand what PE said, he gave you most of the corrections.
I can fill in the holes he left, but as I said before, there are many versions.
If you are just asking for the items in #9 that PE mentions above as being a "kinky"
(or would that be a Jog?) dislocation (Sorry-dumb emulsion makers joke)
yea I could do that. Is that what you meant?
Ray, since I am busy preparing workshops and the book, why don't you do it.
You sound serious...
Originally Posted by Photo Engineer
I was handed the 5 formulas in class and asked to comment. Since enlarging papers were outside of the scope of the workshop, I promised to look into the matter and give the students my comments. Finding such errors when I did the actual research surprised me so I decided to post the results here. I did not say anything in the workshop about this subject.
So, if you have the correct data, please post it here. Otherwise, I have to create a table of corrections and scan it in. Why not do it for me if you have the same thing at hand, and do it with my thanks and those of the rest of the interested parties. BTW, this is NOT my enlarging paper formula by any means. The only similarities are the use of Silver, halides and Rhodium. It uses a Sulfur sensitization and inactive gelatin. There is quite a difference! ;)
So everyone present got a copy already?