I am sure , if you want to produce your original Autochrome , biggest drawback is cost of

Patent Blue V other name Food Blue V ,

C.I. 42051
CAS NO 3536-49-0
EINECS NO. 222-573-8
FORMULA C27H31N2O7S2·0.5Ca

Bis[hydrogen [4-[4-(diethylamino)-5'-hydroxy-2',4'-disulphonatobenzhydrylidene]
cyclohexa- 2,5-dien-1-ylidene]diethylammonium], calcium salt (2:1).

Its supplier is Sigma and 25mg costs 85 dollars. Autochrome Recipe -search for it , its inside of APUG archive - requires 25 grams. Cost is 85000 dollars.

I asked to myself , why it is so expensive , I think I found an answer but I am not sure. It can be a product of marine life and these microorganisms kept growing and than the dye removed. I read that its a very low yield and not for mass production.

I am interested in biology for a long time and I know bacteriorhodopsin have a common way of production and high school students grow them at their school lab for mixing with plastic and read and write in a mass with crossed beams.

I found a patent and Germans had had invented a new bactery and yield rate increased 16 times.

Microbiological method of the biosynthesis of natural blue-violet colorants ...
Tjhing-Lok Tan et al

Patent number: 7901914
Filing date: Dec 20, 2001
Issue date: Mar 8, 2011
Application number: 10/451,518

You can reach it via google patents.

I will write more later.

Mustafa Umut Sarac