SECOND COAT – DICHROMATED GELATIN (coat sensitive to U.V.)
- Quantity of preparation (in cubic centimeters by square decimeter cc / Dm2) : whatever is the chosen formula, the theoretical quantity of mixture of gelatin is 7,3 cm3 by dm2
formula : surface of the plate dm2 X 7,3 = volume of mixture cm3
Ex : for a plate of 50 X 60 cm, the formula will be : 5 X 6 X 7,3 = 219 cm3
|
Size of plates |
Quantity of mixture (with formula above) |
|
30 X 40 cm |
87 cc |
|
50 X 60 cm |
220 cc |
|
60 X 80 cm |
350 cc |
|
69 X 92 cm |
463 cc |
Gelatin dichromated formula (To make the day of the use) :
|
Size of plates |
50 X 60 cm |
|
Photographic gelatins* (to mix gelatins (hard, middle-hard, soft) |
17 gr |
|
Water |
200 gr |
|
Potassium dichromate** |
1,75 gr |
|
Ammonium dichromate |
1,75 gr |
|
TOTAL DICHROMATED GELATIN |
220 cc (environ) |
* To preserve in the undercoat its capacity to be correctly printed, it is necessary to adjust the proportions of the various hardness of photographic gelatins according to the temperature of the workshop. If the temperature is raised, to increase the quantity of hard gelatin. If the temperature is low, to increase the quantity of soft gelatin.
** potassium dichromate can be only used. In this case add the weight both bichromates indicated in the table.