Opaque Plastic Diffusion

[Stephen Frizza]

Has anyone here heard of a contact printing technique in which a sheet of opaque white plastic is lain between the film being printed and the glass plate which is weighing down the film.

I have heard that it was a diffusion technique used in Ilfochrome / Cibachrome contact printing and have a hunch it was to help with issues in contrast? but this is just a hunch. Has anyone gotten experience with this Contact printing methodology? what plastic sheeting is used? and what is the true reason behind this method?

~Steve
The Lighthouse

 

[Charles Webb]

I believe it might be very difficult to get light to pass through anything opaque. Opal glass both "flashed" and true opal will work between a light source, over the negative and paper. I have used a white opalized plastic material from Home Depot for B&W diffusion. Worked, but not as good as an old fashioned sheet of Kodak's Opal glass. Might try a large PPG (Pittsburg Plate Glass) dealer.


Charlie........................................
I kind of wonder why you need a diffused light for contact printing?

 

[Captain_joe6]

It sounds to me like you might be aiming in the direction of unsharp masking. Its probably the most complicated thing that I've ever tried to wrap my head around, photographically speaking, but there are some folks who make it look like riding a bike. Do some searches, both google and APUG, and look for the name Alistair Inglis. I don't know about the first name spelling, but I'm sure about the last name. Cool guy, really knows his stuff.

 

[Stephen Frizza]

I have never ventured into diffused light for contact printing, but i know of two printers who use to print cibachrome whom mentioned the practice of using a white plastic sheeting that let diffused light through. and was used as I mentioned above. I no longer have contact with them and this has always been something that has sat in the back of my mind as a printing curiosity. Has anyone here done cibachrome or ilfochrome contact printing?

 

[z-man]

diffusion con fusion

I have never ventured into diffused light for contact printing, but i know of two printers who use to print cibachrome whom mentioned the practice of using a white plastic sheeting that let diffused light through. and was used as I mentioned above. I no longer have contact with them and this has always been something that has sat in the back of my mind as a printing curiosity. Has anyone here done cibachrome or ilfochrome contact printing?

see my posts in gelatine threads-in one i give the instructions for how i used diffusion and created masks, spreads and shrinks in vacume contact frames that were repeatable and ordered by clients specifying in .001 inch requirements

this was in the adv biz in nyc in the 80's and in boston in the 90's

this work was billed at $125/hr in 1983

the whole "unsharp mask" concept was eroniously started by kodak in thier literature where they used a non-repeatable and uncontrolable way to create litterally unsharp positives form negatives

my methods were derived from my pre-press training as a 4/color stripper

i can remove the confusion from your mind but can't do it now -i'll be back another time -read my posts first then ask qusetions and i will answer them

vaya con dios