FotoDave@aol.com
Sat, 06 Mar 1999 21:44:20 -0500 (EST)
<<Well, not exactly mad, just lacking in differentiating between RGB and CMY.
You're thinking in RGB, but those darn filters are CMY, which means that when
you filter out everything but magenta (which is what the magenta filter does),
there is no effect on the cyan filter.
But color correction filters are not like the color separation filteres (the
high pass filters) where (theoretically) only one color is passed while others
are filtered. Color correction filters still pass a large amount of the
original light through. For example, a 30cc Magenta filter will reduce the
amount of the original light by one stop of Magenta light, but a lot of the
original light still pass through. If there is another 10cc Yellow filter, the
original light will be reduced by 30 density unit of Magenta *and* 10 density
unit of yellow. Isn't this the basis of how color printing (balancing) works?
Liam's suggestion of using filter in lowering contrast is an interesting one
although I can't seem to think theoretically whether it will work or not. If I
think in one direction, it seems to work. If I think from another direction,
it doesn't seem to work. But I do have a color enlarger, so I will try it out
next week and let everyone know. :)
>> There was always amazement when I used three projectors each with its
own R, G, or B filter, and the screen showed white when they were projected
together. Using filters in front of one white beam will always act as CMY.
>>
Exactly! That's what I meant when I said a while ago that RGB is for light
(although I admit that I didn't use the rightest term, I probably should have
said that when we consider red, green, and blue as additive primaries, we are
talking about adding lights).
Dave S
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