In your experience , how many wet plate could be sensitized per one gram of dye ? How it is being calculated ?
I am asking in behalf of the OP because he thought I was trying to block his posts.
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).
Thank you PE and Ian.
Ian , can you tell me what is mol of silver ? Does 1 grams of dye make a solution enough to plate be able to soaked ?
How many mols of silver does wet plate 8x10 single needed ?
I have just googled and learned 1 mol of silver is 107 grams. We can sensitize 1 kilogram to 10 kilograms of silver with 1 grams of sensitizer.
It makes the sensitizer dye economical , no need to experiment with large quantaties I guess to determine the formula.
What is the minimum order quantity of EK order PE ? Can we order miligrams ?
And How many grams of silver one 8x10 wet plate uses ?
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?
Wall has a good discussion about sensitizing collodion emulsions with commercial dyes. His book, "The History of Three Color Photography" is available online--the collodion discussion starts about page 222. Here is the link:
There is also a book from 1905 by Oscar Klein which is also online, "Collodion Emulsion and its Applications..." which deals with making collodion emulsions color sensitive using common dyes. That link is:
In addition there are various Kodak publications from the 1920s which deal with sensitizing collodion, as I recall. Search the topic through Google Books.
Thanks-this is a big help
Originally Posted by falotico
Thanks as well and regards
Originally Posted by falotico