P3D Re: Anaglyph in Photoshop

[Marvin Jones <Campfire@xxxxxxxxxxxxxx>]

Message text written by INTERNET:photo-3d@xxxxxxxxxxxxxxxxx
>Jim was right, Mike.  You *can* cut a greyscale channel out of a
monochrome
image, and then paste it into a RGB channel.  All channels are monochrome
by nature. (This little confusing bit is why I simplified the instructions
in the
first place.  The correct answer sounds wrong.  :^)<

Actually, this isn't entirely necessary, either. If you are dealing in
monochrome, there is no need to copy just a channel from an RGB copy; you
can simply copy the entire image. Remember, that each channel in an RGB
image is, itself, a greyscale image. So an entire grayscale left-eye image
can simply be copied into the red channel of an RGB right-eye image. Since
in a monochrome RGB image, all the channels are virtually identical, this
has the same effect. Several people here have suggested dumping the green
channel, but I don't advise it. This leaves a harsh red/blue image, whereas
leaving the green channel makes a much more "normal" red/cyan image.

My original instructions were based on the assumption that whoever first
asked the question was trying to do COLOR anaglyph. In this case, it IS
necessary to copy only the RED channel from the left-eye image and use it
to replace the red channel in the right-eye image. This provides a finished
image with reasonably natural colors, but with red/blue fringing that
creates the stereo. Of course, when viewed through anaglyph glasses, the
colors in the lenses often clash with the colors in the image. I've always
thought color anaglyph was pretty disastrous, but people keep trying. If
you have just the right combination of colors in your original image, it
can sometimes come CLOSE to working.


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