Blue filter for split printing..

[Robbie Bedell]

I have started to experiment with blue/green filter split printing rather than the Ilford magenta filters I was using. I have a glass #47 blue which is recommended, but it is VERY dark... So dark I can hardly see the image. Can I switch to any blue filter or does it have to be the dark #47? Any suggestions would be greatly appreciated! Robbie

http://robbiebedell.photoshelter.com

[Kirk Gittings]

This is a new one on me. What does a blue filter do?

[Drew Wiley]

The VC paper has one emulsion sensitive to blue, the other to green. Theoretically, green
and blue sharp-cutting filters would do the best job, and that's what I use for split printing
on my high-output VC54 coldlight for 8X10 printing. But for all practical purposes yellow and magenta filters can be substituted, and will allow more visible light thru. I've compared
results between the GB method using glass filters on the coldlight, GB on my additive
colorhead, and MY on my subtractive colorhead, and have be able to obtain identical results.

[Kirk Gittings]

Yeah I've always used the yellow/magenta filters.

[Andrew O'Neill]

Robbie,
I use the darkest blue Roscoe filter from a multi-pack that I ordered from them years ago. It's not nearly as dark as my kodak wratten #47. I get very high contrast with it. I also use their darkest green filter.

Kirk, doesn't a magenta filter act as an ND filter?

[Kirk Gittings]

Not that I am aware of. For as long as I have printed VC I have used y&m filters, originally the old Kodak ones, then some Ilford ones and now a color head. They always worked fine-maybe I missed something over the years?

[bob carnie]

The Ilford multi head uses a combination of blue and green light.

I use the magenta and yellow on my equipment or the magenta and yellow filters by Ilford.

Not that I am aware of. For as long as I have printed VC I have used y&m filters, originally the old Kodak ones, then some Ilford ones and now a color head. They always worked fine-maybe I missed something over the years?

[Sevo]

You NEED a green respectively blue blocking filter - most "blue" filters are of the merely attenuating "colour correction" kind that gently reduces red and yellow, and are unsuitable for green/blue separation purposes. But for Multigrade, you'd better go the yellow/magenta way - these do the job just as good or even better, and as they include the (useless for the paper) red channel on each filter, they are much easier to see by.

[Bill Burk]

Magenta and Yellow filters are simply the additive result of Blue+Red and Green+Red. It's the Blue and Green light doing all the work. Additively adding Red does nothing to the paper, but helps you see the light better.

[Steve Smith]

The VC paper has one emulsion sensitive to blue, the other to green.

Actually, there are often more than two layers of emulsion. They are all sensitive to blue and their sensitivity to green varies with contrast.


Steve.