Hi Mustafa,
Nice to hear from you again. You always spark great discussions and you've gotten some really sound advice here already.

This one has me a bit confused, though. There are two reasons to pursue historical information: 1) as a 'purist' whose primary interest is basically in technical archeology - facts for the sake of fact alone, and 2) as a creator of art who yearns for the look of an extinct product. You can be both, of course, but the direction you start your investigations is very much determined by which is more important to you. You say that your friend has tried pan x with a monobath, so that hints that he may be looking from an artist's viewpoint.

Kirk is spot-on about the costs involved if you hire an outside lab. Ouch! Really. Keith is smart to point out the pitfalls of comparing current emulsions with old, even if they carry the same name. If art is the primary goal (and, of course, pure science can always follow later), perhaps you and/or your friend should learn plain, old-fashioned emulsion making. It might seem like a backdoor approach, but it is after all how it all started. Reverse 'reserve engineering' if you will.

Best,
d