technology of the noble compression matters goes back to the 40's
19th century, in which the first negative/positive process was
developed by Henry Fox Talbot.
The gum bichromat is without doubt the king discipline
of the noble compression matters. No photographic copying technology
offers as many creative possibilities as the gum
Only this process offers a nearly unlimited selection of basis
papers or colour nuances and permits to let whole picture parts
disappear unnoticed or put important elements into the foreground.