Looking for dyes, additives or a formula to sensitize collodion to >800nm (infrared)
After reading the giant thread 'A real formula' with PE in the Forum: Silver Gelatin Based Emulsion Making & Coating, I'm a little confused.
There are lots of hints ond advices for dyes to create an emulsion with superpanchromatic or, at least, expanded red or infrared sensivity. But these formulas are all just for dry plates.
My collodion plates are just sensitive to blue light.
After production of Kodak HIE was stopped and there was no other real infrared film material on the market anymore (forget Rollei and SPX, just 700nm / EFKE and Konica stopped production) there is no chance to continue real infrared photography.
So I just wanted to try some dyes to expand/shift sensitivity up to 800 or more nm with collodion wet plates.
The wet collodion process is devided in two parts.
1. The collodion
2. Sensibilization in silver nitrate sol.
Where, when, how and how much do I have to add the Neocyanine or the 3,3'-Diethyloxatricarbocyanine iodide.
Do I have to change the developer (iron(II) sulfate), then?
How about fixing, then? Any experience?
...and sorry about my horrable English!
I suppose you would then have to sensitize the plate in total darkness then. When you sensitize with neocyanine is beyond me. Time for you to start experimenting... and spending heaps of money! Those dyes are not cheap!
Originally Posted by Andrew O'Neill
well, I already sensitized my plates in the darkroom tent in a small box with silver nitrate sol. (inside the box in complete darkness).
So I hope, after a few tests there won't be need for any further check views on the plate.
But I actually still don't know how much and which dyes to add, how to develop then (still just iron (II) sulfate sol. in darkness - what time then) and how to fix then.
Maybe here is someone else, who tried it - I hoped it's worth asking here ;-)
Maybe you're right and in the end I will need to try it alone the whole rocky way...
Uhm... no Mustafa, there are no combined results for 'collodion' and 'infrared' in the search engine (It was my first try) for APUG forum posts... (so why do you claim the opposite?)
Originally Posted by Mustafa Umut Sarac
That's why I asked the community.
Do you want me not to ask anymore?
AFAIK, there are no examples of dry plate, wet plate or Daguerreotype plates in the literature. I know that they were worked on at EK and at RIT many many years ago.
I'm not saying it is impossible, I'm saying that some concerted work by a lot of people was not successful. It may be that with more modern dyes, it might work.
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H.W. Sands Corp www.hwsands.com manufactures many types of imaging dyes and chemicals.
Be prepared to part with a LOT of money ($ hundreds/gram). Some dyes are very costly, and there can also be a "convenience fee" attached to small orders.
Off the top of my head, typically 10-100mg of dye is required for 1 mol of silver (in the form of a silver-gelatin emulsion) The actual figure depends partly upon the size and surface area of the grains.
Therefore, it's not a simple matter to say x grams of dye will sensitize y number of plates.
When it comes to wet-plate, it may be a totally different number, or it might not work at all.
In the early days, plates were spectrally sensitized by soaking them in a dye solution.
"The Photographic Emulsion", Carrol & Hubbard, Ch11 touches upon the mechanisms and variables of dye sensitization.
A search on "dyes" and "spectral" on APUG should reveal greater detail.
AFAIK, Sands does not list many (if any) photographic spectral sensitizing dyes used in classic systems. Kodak and Fuji make their own. I have posted a list of dyes that Kodak sells (or sold via Eastman Chemicals).
What if the first dye is wrong, or what if the amount is wrong. Then the experiments start.
And the cost of a dye runs between $100 to $300 / gram of dye.
I am also interested in increasing the light response of colloidion emulsions. Could you use an inexpensive dye like eosin or erythrosine first and see if you get a better spectral response? My guestion is whether the dye goes into the colloidion mix ,the silver bath,or a seperate bath altogether. My guess would be the colloidion, since the dye may react with the silver
You could add the dye to the pouring stock to save the main stock. About 2ml of a 0.1% dye solution in alcohol per 100ml sounds right from my gelatin work.
Any thoughts guys?