Definitions by Eccko

Diazo 

It is also known as the blue-line or blue-line process.
There are two components in this process:

1. the diazonium salt: a light sensitive chemical

2. the azodye (AKA coupler): a colorless chemical that combines with diazo to produce color

Diazo is the process equal the Blueprint ,which is commercial terminology

Diazo by Eccko June 3, 2010