My images
are captured by large format cameras using black and white (silver) film
hand processed then printed on Silver Gelatin based paper, hand coated
Platinum/Palladium paper or with the Ambrotypes that are printed on glass
directly in the camera.
Silver Gelatin 1890-1960
This is the most modern of the three processes I use. Light sensitive
silver salt particles are suspended in a gelatin coating (by machine)
on the paper. The film negative is either placed directly on the paper
or in a projection enlarger above the paper. The paper is then exposed
to light thru the negative for a very short time. The exposed paper is
then developed chemically with a metol, sodium sulfite/carbonate and potassium
bromide solution that turns the silver salts into silver metal. The development
action is stopped by an acid then cleared (fixed) in a sodium thiosulfate
solution to wash off any unexposed pieces of silver creating the black
to white tonal scale on the white paper base. The image is washed with
water then toned in selenium for permanence.
Platinum / Palladium 1873-1890
Noble metals sodium chloroplatinate and sodium palladium are mixed with
ferrous oxalate to form the light sensitive solution that is hand coated
on a slightly acidic paper. Unlike a “Silver Gelatin” the
Platinum/Palladium solution is not suspended by a gelatin layer and soaks
directly into the paper taking on the matte texture of the paper. Once
the solution is dry the film negative (which size determines the final
print) is placed directly on the paper with pressure then exposed to UV
light usually about 4-6 minutes. Once the ferric oxalate is exposed to
UV light it becomes ferrous. The image is then developed in potassium
oxalate turning the ferrous coating into the platinum/palladium metals.
The image is cleared by slightly acidic solutions and washed in water.
The end result is a rich warm soft image that is the most stable and permanent
of all of the photographic processes. This process was short lived due
to the high cost of platinum and the complexities of paper coating. Today
platinum is trading as high or higher than gold.
Glass Ambrotype 1850-1860
The Ambrotype is an image created on a plate of glass using the “Wet
Plate Collodion” process and is also the very basic form of creating
black and white photographic film. A black glass plate is coated with
“collodion” (a nitro-cellulose film substrate for the silver
to adhere) which is a mixture of nitrated gun cotton, alcohol, ether,
cadmium bromide and ammonium iodide. The plate is then placed into a bath
of silver nitrate for a short time which makes it light sensitive. While
the plate is still wet with which is now a silver halide coating and in
a “safe light environment” it is placed inside the camera,
exposed, removed then immediately developed with a ferrous sulfate solution.
The term “wet plate” refers to the fact that it needs to remain
wet to be sensitive to light. All of this needs to happen within a 15
minute time period. The development process is stopped by water then the
excess silver that was not struck by light is dissolved by a sodium thiosulfate
fixer bath. The plate is then washed in water, dried then coated with
a gum sandarac and lavender oil varnish. This beautiful process was very
short lived due its extremely dangerous nature as well as the need of
a traveling darkroom.
Images can be purchsed direct from
me (303 912-4668, jeffg@graymatterimages.com) or from one of my represenatives.
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