Well, my post should have said "1965" which is about the date range of the last of the emulsions in the book that woody Thomas edited. And that is about the time I was helping edit Grant's Book (1970 or thereabouts). Sorry for the type. My eyes are in very very bad condition after the last few weeks. I am also fighting a keyboard that likes to miss keystrokes and that doubles others.
Originally Posted by Jerevan
Also, I forgot to add that the Formulary now sells glass plates in 4x5 and 8x10 and will custom cut as well. I have also found a source for old plate holders and for hand made new holders but the latter I dismiss due to the extreme in price.
In books of the sort that are referenced here, one must remember that both the editor and the author are given guidelines of what may or may not appear in a given work. In this case, that would cover a lot of people and a lot of information. When I published anything, my work was both edited and "vetted" by a group of people who could "veto" words, phrases, or even whole topics thus leading to a severe "emasculation" of the topic, and thus the emulsion published in Haist is actually nearly unusable due to omissions forced by the vetting process.
You may note that some of the formulas use Cadmium. At the time of writing, Cd was obsolete and too dangerous to use in a common lab and had been replaced by at least two organic chemicals. The wash is given in terms of conductivity, and the addition method of the first silver is given as what is essentially a "dump". Mixing speed is vague. The gelatin used is assumed as active. This all points to formulas from the 1945 era, as they read much like those of that time. Specific addenda for keeping and other photographic qualities are not mentioned.
That is the problem that I see. So, one can make a simple emulsion such as these, but there are about a dozen added sentences to each one that would significantly improve each and every one.
Here is an example. To every formula, one can add TAI (Tetra Aza Indene) as described by Jim Browning and available from the Formulary. Use of this chemical will just about double or triple the keeping of the coatings and will lower fog! Washing to a given vAg would also improve the emulsion, but even using conductivity, a concrete method of measuring conductivity would help and none is really given in the article!
So, that is my take with this and why I think that the work must be modernized. And, BTW, reading my book for the last time I find that I could have done a much better job. My problem is that I am just running out of time and patience. ;)
thanks for the elaborations. I am sorry to hear about your eye condition - I hope it gets better. Your contributions are very valuable.
I think that even if you find faults (who doesn't with his own work?) with the book, it is much, much better than no book!
You can spot a cat lover mile away. Thanks for the referral for the glass company. I'll take a look. Searched on Ebay and haven't found any plate glass holders. I'll keep searching. Again the process is very intriguing. Looks like you can make a batch and refrigerate it until you need it. I would like to coat a bunch and store it. I'm sure the emulsion is good for coating paper for prints.
The average emulsion can be stored as a gelled material at about 3 deg C for nearly a year or more. With a better preservative against bug attacks it can be extended to about 2 years or so. Fog growth can be inhibited by TAI at the proper level.
Also, the emulsions that I have been making are so repeatable that I am now blending mixes, so I can make 400 g this month and two months from now, down to 200 g, I can make another 400 g, mix them and have 600 g of good stuff. I see no reason why the slower emulsions of any sort that I have read on-line could not be blended in this fashion.
I am going to do some legwork on this TAI, see what I can find out.
TAI is quite benign AFAIK, but I don't have the CAS # OTOMH and the IUPAC name escapes me right now. It is used in Europe at all film manufacturers and since Fotoimpex is now selling the DVDs, maybe you can get it through them. I'll look up the # here somewhere.
It was first patented by Birr of Agfa fame in the '30s.
By googling the name, taken from the Formulary homepage, I got CAS# 2503-56-2. Great to know that Fotoimpex is selling the DVDs! Yes! :)
I gather it has this little name too: 4-Hydroxy-6-methyl[1,3,3a,7]tetrazaindene.
As for emulsion stabilizers, this thread seems to be a worthwhile read: http://www.apug.org/forums/forum205/...abliizers.html
I think that is an excellent book. Lots of good information in there. I had forgotten about that thread entirely.
I think you have the right CAS #.
Go here: http://www.fotoimpex.de/cgi-bin/shop...che=1324397154
for the DVDs in Europe.
With regard to glas plates, Tru- Vue galss is a fine glass fot plates AND final support. It can be found on Ebay and can be cut to order. I use it for 5x7 glass plate negatives, and for my final support. It is not quite water-white($$$$) but is far less green than ordinary window glass.