smieglitz
Member
mrcallow said:Thank you David, smieglitz. You are free to elaborate...
Never done these but my understanding is:
Tintypes/Ferrotypes and Melainotypes (all the same thing) are direct positive wetplate collodion images made on a sheet of japanned (blackened) iron plate...contemporary workers use anodized aluminum plates as well. As with daguerreotypes and ambrotypes, tintypes are direct positive images and unique physical objects which must be copied optically in the camera for any duplicates to be made. All of these images are also reversed optically as mirror images of the subject;
A Chrysotype is a print made using light-sensitve gold salts (google Mike Ware or Terry King for more information);
An Anthotype is a print made with the juices of certain flowers (I believe the process was invented by Sir John Herschel the astronomer, inventor of the cyanotype process, the person that coined the word "photography" and a friend and portrait sitter for Julia Margaret Cameron);
The obscure dusting-on process involves the application of a powdered pigment to a wet/sticky photographic matrix. I believe honey is used and the matrix behaves something like a lithographic plate might repelling the pigment in proportion to moisture content (but don't quote me that...IIRC, I think the Fresson family also had something to do with the origin of this process but again...);
I also just remembered the contemporary gumoil process of Karl Koenig. It is like a cross between gum bichromate and an oil print. IIRC, a dichromate print is made from a contact positive. This image is essentially invisible (but negative) consisting only of an unpigmented gum arabic + dichromate emulsion which hardens in proportion to exposure of the dichromate sensitizer. Water washes away areas of gum that have not received sufficient exposure (just as in the normal gum bichromate proces). Once dry, these cleared areas leave the paper substrate exposed. Oil paints are then rubbed onto the paper surface coloring it in part and then the excess oils are rubbed off. The remaining gum image is then etched back a bit chemically, washed again and dried. This leaves new areas of paper revealed. More oil paint is rubbed on to color these new areas and blend with earlier colors. The process is repeated until the print looks satisfactory.
Joe