Jeff R. wrote:
I have long enjoyed stereo photography, in cross-eyed and parallel
free-view, anaglyph through coloured glasses and cross-polarised
projections.
I was interested to see the "stereo" effect (unintentional) which can be
seen on some webpages which use strongly contrasting colours.
Like so:
http://www.mendosus.com/photography/colour-stereo.html
Can everyone here see the apparent differences in depth of the coloured
text on that page?
Can anyone resolutely *not* see it?
Yeah I see it.
Does it work with one eye closed?
(It doesn't for me.)
Likewise, it disappears for me with one eye closed too.
More interestingly, can anyone offer a simple, understandable
explanation for the effect?
Others have suggested the different focal length for
different coloured light, but I don't think it would make
that much effect, plus if that was the cause it should still
be present with one eye closed. Also if that was the cause,
the stereo effect should increase as you get closer (as the
difference in focus increases), and disappear with distance.
Whereas I find the opposite, as I get closer the 3D effect
lessens, as I get further away it increases until I'm about
3ft from the monitor. I put it down to an effect caused by
the Bayer filter on the retina, and a slight bug in the
Brain's raw image convertor and 3D engine. ;-)
Googling produces some joy, but not much. (Too tight to pay for research
papers.)
Anyone think there could be implications here for landscape photography?
(Or is the effect too gross/unsubtle?)
I've observed similar effects with highly saturated slides
too - eg photos of flowers, green meadows & blue sky.
Curiously the effect seems to disappear when projected. When
I first saw the effect with slides, I thought the effect was
caused by the different colour layers, but then I noticed
the perception didn't reverse when the slide was turned
over. And thinking about it more it couldn't be, because on
a slide the primary colours are made by subtraction from
multiple layers.
--
Jeff R.
(more than one dimension)