Just posted this question in another thread. If using a handmade gelatin emulsion on glass, what's the best method for developing? Also, is it possible to use a direct positive silver development process with a gelatin emulsion on glass to produce an ambrotype effect?
Traditionally an Ambrotype is a wet-collodion emulsion coated on a glass plate, sensitized and exposed in the camera while still wet, processed while still wet and then fixed and dried. It is really a thin negative image, but due to the type of developer used results in a negative image that has a rather light tone to the developed silver, and when backed by a piece of black paper or velvet, appears as a positive. There is no reversal, or direct positive type of processing done, it is just the color of the developed image is lighter than the black backing behind the glass plate is darker, making the developed image appear as a positive (by optical comparison to the background).
I know. Been doing some searching on how to recreate that effect with modern emulsions and have found modern tintype kits but no information on how to do an ambrotype with either albumen or gelatin. Maybe it can't be done with modern emulsions?
It can be done with handmade emulsions, as they are not 'modern emulsions' in the strictest sense and can create very low contrast images. This is just what you need for Ambrotype I would think.
I know. Been doing some searching on how to recreate that effect with modern emulsions and have found modern tintype kits but no information on how to do an ambrotype with either albumen or gelatin. Maybe it can't be done with modern emulsions?
There are plenty of people who are doing Ambrotypes and Tintypes (same process on black japanned tin) the traditional way. There are texts available and workshops you can attend, and resources for the supplies needed. Why would there be a need to replicate the results with a gelatine emulsion, when you can do it the "historically correct" way?
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... Why would there be a need to replicate the results with a gelatine emulsion, when you can do it the "historically correct" way?
Formica vs. wood, vinyl vs. leather... "Nudge, nudge, wink, wink. Know what I mean? Know what I mean?"
The convenience of silver gelatin "tintypes" comes at a great cost visually. If you try the commercial product on glass, you'll probably have to sub the plate to get the emulsion to stick. A silane or albumen solution might work.
As Kerik has related, real wetplate collodion is much fun, but inconvenient, and you have to respect the chemistry. IMO though, it really is unmatched in terms of visual qualities.
There are plenty of people who are doing Ambrotypes and Tintypes (same process on black japanned tin) the traditional way. There are texts available and workshops you can attend, and resources for the supplies needed. Why would there be a need to replicate the results with a gelatine emulsion, when you can do it the "historically correct" way?
Because I'm doing pinhole photography in 11X14 format and use exposures of 40 minutes to 3 hours or more, thus wet plate collodion is not an option for me, and I have no plans for putting a lens on my camera just yet....
I suppose it is possible to do a contact print on glass and put a white or gray board behind it. Wouldn't look the same but might be interesting.
Here's a photo I did today. It's an 11X14 pinhole with a 127mm focal length. I shot it on an albumen glass plate negative with a 1 hour exposure time, and then did a contact print on another albumen plate, developed normally in gallic acid, and painted the back of the glass white.
It works, but it aint no ambrotype...
The actual photo is not quite as sharp and is a little lower in contrast, and the scanner I used can't quite get an entire 11X14 so some detail around the edges is missing. Also, when I enlarge the scan there are a series of lines in the upper left hand corner that aren't on the print.
Modern ambrotypes 
Linear Mode
