A
comfortable reading distance is a good starting point for viewing
stereograms on-screen, or on a page. However, drawing back
from the monitor may not only help in viewing larger images,
but increase the 3-D effect. Also, I find the longer I stare
at a stereogram, the greater the stereogramic effect.
Bringing
an autostereogram into focus is a gradual sensation, but switching
from "autostereovision" to normal vision is abrupt,
and can be uncomfortable. I find the best way to avoid any
such discomfort is to breakaway from the autostereogram by
briefly closing your eyes, and then opening them using normal
vision.
All
my stereograms are made to be viewed wide-eyed, as are most
hidden-image stereograms in general.
How
can you tell if your using wide-eyed or cross-eyed vision?
Many times I realize someone is viewing cross-eyed where it's meant for wide-eyed
vision to be used, and they're missing the correct 3-D effect, or unable
to see stereogramic altogether. Unfortunately, there's no easy way to tell,
or coach the casual viewer, but keep in mind that autostereograms using parallel
vision may actually feel soothing to the eyes. Whereas, images requiring
cross-eyed vision can produce enough cumulative eye-strain to produce a headache
if your eye muscles are not use to it. In my experience, staring at enough
images on a regular basis develops the eye muscles (like exercising any other
muscles) to a point where you can view with total comfort... unless, of course
you create stereograms for hours on end, in which case, nothing can save
you.
Why you might see a double image: Especially when viewing
hidden-image stereograms, you may sometimes see a leaner image layered
above a wider image. This is from diverging your vision too broadly.
Stereograms are all made of vertical columns. If vision diverges too
much, your brain will factor in two columns at once, instead of single
side-by-side. This happens more often with experienced viewers.
Why you might see some, and not see other stereogram effects:
There are a couple reasons you might see stereo effects in some stereograms,
but try without success with others.
1) you may be using the wrong vision: cross-eyed instead of wide-eyed
2) your monitor size and screen resolution may be too small, or too large.
Or, it could be a combination of the two. Sometimes, in the frustration from
being unable to view stereogramic effects due to inadequate monitor/resolution
sizes, a viewer might try too hard and end up using cross-eyed vision where
only wide-eyed will work.
IMAGE QUALITY
The
images on this site were all created at far larger sizes. As
a consequence, there is detail, and quality that is necessarialy
sacraficed to display an image on a Web site.
The
final web image is again compromised by the compression-quality
ratio inherent in the JPG image format. I have mostly used
7 on a scale of 12, which means image quality has been moderately
sacrificed, but quite adequate.
Presentation of
a stereogram is best served by as little distraction on the
page as possible. Especially any kind of stray patterns
or words on either side can create visual dissonance.
Color accuracy
is always desirable, but makes no difference whatsoever with
the 3D effect. All images should show a 3-D effect if reduced
to grayscale--or even just black & white.
It's
a lot of compromising, but my justification is to raise autostereograms
to a high art form, and bring pleasure to those people who
find their way to Color Stereo.
