Hi there Can somebody tell me the science behind Ilford multigrade filters and their effect on Ilford multigrade papers? what is the correct method to use them? and if they are could be used with oridinary papers ( other than Ilford multigrade) thanx Shree

-- shree (middlegrey@hotmail.com), September 21, 1999

Answers

The emulsion of variable contrast paper has effectively two components: one low contrast that is sensitive to green light, the other high contrast that is sensitive to blue light. Neither is sensitive to red light, so low contrast filters pass lots of red+green=yellow, while high contrast filters pass lots of red+blue=magenta. The filters also have neutral density added to retain (in theory) the same paper speed.

The correct method to use them is described in the intructions that come with the paper.

Yes, they can be used with multigrade ('variable contrast') paper from other manufacturers. They are not useful with fixed grade papers from any manufacturers.

-- Alan Gibson (Alan.Gibson@technologist.com), September 21, 1999.