to dwross

Thanks for the Tadaaki Tani quote - the two post-war references are a bit late but you prompted me to look again at the J.Opt.Soc.Am paper again and Mueller does quote reparations documents (R. Koslowsky and H. Mueller, Agfa Film Plant, Wolfen, Germany. Reports September-October 1936. Bibliography of Scientific and Industrial Reports (U. S. Department of Commerce, Washington), Vol. 8, p. 873. PB 70053, fr. 831-50.) as 'evidence for the use of gold salts in modern emulsion manufacture'. This is a Library of Congress microfilm I probably need to see. Tani seems to have published as recently as 2007 on gold and there seems to be some current research from China on gold for X-ray films but this - though interesting - is way off my beam.

Steigmann I know nothing about - I'm guessing much more recent than the 1940s/50s.

Thanks too for the UK patent number for the Ron Collins patent - I've found the US patent equivalent US2399083 - according to Hercock, R.J. & Jones, G.A. (1979) Silver by the ton: the history of Ilford Limited, 1879-1979. Collins reckoned that Koslowski had not found the idea time to add the gold salts - he favoured prior to digestion but after washing.

As I say I am trying to establish an evidence chain that Koslowski's work on gold was used by others in post-war production either for commercial or aerial reconnaissance emulsions - there's a solid and logical reason why Ansco had access to K's research but was the information news to Kodak? According to Collins it was certainly not news to Ilford.

to Photo Engineer
Thanks for posting in reply - Sheppard published in 1925 and Mueller cites Jenisch (1926) and Carol and Hubbard (1928) as attempting to push that research forwards with colloidal particles of gold and platinum. Having spoken with a couple of Kodak Harrow research scientists (now retired), their recall is that Kodak began to use S+Au sensitisation in the 1950s and felt there was some connection with the work done by Koslowski. Wether Kodak got this information from the reparations haul of Agfa documents, from analysing others' products or from pure research is interesting.

I hadn't appreciated the applicability to AgBrI emulsions only.

One intriguing snippet from the Hercock & Jones history of Ilford if that the RAF preferred Ilford emulsions for photo recon work and that Ilford was prevent from patenting one advance - I presume in emulsion chemistry - by the Ministry of Aircraft Production. This was apparently called Tetragam - I though it might be a mis-spelling for Tertragram (four letter word i.e. "gold") but I think I'm barking up the wrong tree. Could it refer to a tetragonal crystal structure and be some grain-shape improvement - an early tabular grain emulsion? Ring any bells?

To you both many thanks for the leads and ideas.
David