Re: PHOTO-3D digest 2113

[P3D John Ohrt <johrt@xxxxxxx>]

P3D Ray Zone wrote:

> With Additive Filtration (Light Primaries) the combination of
> Red/Green/Blue mixed together makes White.  With Subtractive Filtration
> (Pigment Primaries) Red/Yellow/Blue mixed together makes Black.


Sorry for a slow response.  What you say is not relevant to the issue at
hand.

You are wearing filters in front of your eyes.  What matters is whether
the background is black or white.  How that is achieved is irrelevant. 
With a white background, the background will appear to have the colour
of whatever filter is in use.  Likewise, a colour matching the filter
will be percieved as the colour of the filter.  Hence, an eye behind a
red filter cannot distinguish red from white, given the intensities are
appropriately matched.  It does not matter if the technology of the
image is reflective or emissive.

The use of a white background maybe convention since early depictions
where done using reflective technology (ie. paper and ink) and it is
much cheaper to print on white paper than black for a given level of
legability, I don't know.  I would suggest a white background continued
to be used even for computer displays since hardcopy is easier to
produce and you can use the same glasses for softcopy and hardcopy.
However, the black background may be artistically desireable in some
cases, but swap the colours associated with the FOVs so the viewer
doesn't have to use non-standard glasses.

Regards,
John

--
John Ohrt,  Regina, SK, Canada
johrt@xxxxxxx


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