P3D Re: Colour Anaglyphs

[aifxtony@xxxxxxx (Tony Alderson)]

>Dale Walsh noted:
>In 1983, I bought two French magazines with colour anaglyph images on
>their front covers and inside: Photo and Paris Match (which Ray mentions
>on his site). The Photo magazine has photos by Pierre Malifaud, Francis
>Giacobetti, AndrČ Berg and Emmanuel Malifaud. The latter claims to have
>invented the colour anaglyph process. His explanation of the process he
>patented involves separating the colours into cyan, yellow and magenta
>with the black being discarded. (...)
Does this sound like what we have been doing with RGB channels or is it
completely different? <

It is essentially the same, only in the CMYK color space rather than RGB.
Back in the "old days" (before desktop prepress), about the only way to
accomplish this task was to fiddle with color separations. But the Magenta
& Yellow seps were taken from the Left image, and the Cyan sep from the
right.  Originally, I took the black sep out of the anaglyph, but client
demands for more "snap" eventually demanded a controlled black layer, which
made the color look better at the expense of additional ghosting.

It is unlikely that E. Malifaud "invented the color anaglyph process." In
fact, I have learned that it is risky nowadays to claim priority in any
stereo process. Usually, such sitations are, at best, independent
rediscoveries of old techniques, and claims of invention are, sadly,
proclaimations of historical ignorance. Not that I have a problem with
that... One of the problems in establishing priority in stereoscopy is that
practitioners are often extremely possessive and secretive about their
techniques.

But Zone cites several color anaglyphs before the Paris Match publication,
including my own work at 3D Video the year prior. My color anaglyphs were
made with the same CMYK manipulations mentioned by the French, but I know
my ideas were based on the earlier photographic prints of John Rupkalvis,
who was influenced by the work of Leslie Dudley. And so on.   If Malifud
actually patented anything, it's clear the patents have proved
unenforceable.

>continuing:
>(...)less retinal rivalry occurs using True Color but that these images
>are less colourful or more monochromatic but look quite good besides that.
>This seems normal to me since one of the channels is grey scale or
>monochromatic.<

Well, of course, the key to this technique is that it is a compromise
between the monochromatic and polychromatic anaglyph; nudging the result
towards the monochromatic, but still retaining some color information. I
have used such manipulations myself in the past. But "True Color" is
misleading name, as the color is certainly less than full spectrum. This
makes the trick difficult to use in commercial applications, as the client,
in my experience, is more concerned with how the color looks with the
glasses off, rather than how the 3-D looks with the glasses on.   (Please
don't give me a lot of grief about this. It ain't my druthers. But those of
you who think about making money with stereoscopy might consider that the
cash-paying customer has a different agenda than yours.) But Boris is a
"fine artist" manipulating his own work; and can do as he wants.  He'll
probably start designing for the peculiar, and oddly pleasing, color
quality of channel variations.  More power to him.

Tony Alderson




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