A set of 10 black aluminium plates in 18×24 см for tintype. Exact size 178 × 238 мм, 0.6 mm thick: black on the front, bare aluminium on the back.
What it is for
The black coating is not a finish but the condition under which the process works at all. A collodion image is negative by nature and thin; it only reads as a positive with black behind it. Aluminium instead of the historic iron sheet does not rust, weighs less, and needs no japanning before you shoot.
How to use it
The plate loads into a large-format holder, so check the format against yours: different holder makers cut different seats for the same nominal size. Degrease the plate before flowing it — whether the collodion lies evenly depends on that.
How it compares
Wet plate is a mid-nineteenth-century process: the plate is flowed with collodion, sensitised in silver nitrate, exposed and developed before the layer dries — the whole thing in a matter of minutes, from pouring to fixing.
The alternative is glass plates for ambrotype, where the image is transparent and backed with black. Metal is tougher and survives being dropped; glass gives a different depth and a more historically faithful look. For a first attempt aluminium is the practical choice.
