|
|
 |
| |
 |
 |
|
|
 HILE THE PLATE IS BEING READIED, the image is also prepared. A positive transparency is made from either an original negative or a copy negative. This film positive, which must be made the size desired for the final print, is then contact-printed under ultraviolet light to a gelatin-coated paper (known as carbon tissue) which was previously made light sensitive by soaking it in a solution of potassium bichromate, then dried. |
|
|
The tissue and positive prior to exposure |
|
In this process, the action of the light through the film positive changes the melting temperature of the gelatin. Areas exposed to light have a higher melting temperature and are said to be "hardened" and less exposed areas stay the same.
|
|
|
|
|
 |
|
|
|
