Price € 14.00 Net Price € 11.00
Diazo (4D) - 4D 4-Diazo-diphenylamine hydrogen sulphate-copolymer with formaldehyde
It replaces the Potassium and the Dichromate Ammonium in the techniques that use the Arabic gum: Bichromate gum and Gum oil.
The product does not have the toxicity of the dichromate and does not cause damage to health as the latter.
In powder form it can be stored in the freezer for up to a year while in solution it must be used within 24 hours.
The solution in good condition has a pH between 2 and 3.
It must be handled in safety light both in powder and in solution.
During the drafting of critical colors such as Magenta or Yellow can be used a lamp with a power of 15W maximum at a distance of at least two meters.
It is much more efficient than dichromate, in solution it is used with a concentration of 0.5%. Higher concentrations do not give any advantage, they even worsen the quality of the print.
The exposure time is halved compared to the dichromate. The sizing of the paper can be in Gelatine or better still in PVA (Polyvinylalcohol). The ratio Diazo Gomma is 1: 1.
Any yellow residues can be removed by washing in suitable solutions.
It is not possible to adjust the contrast with this product, normally a suitable negative is produced.
Diazo - 4D 5g