P3D Re: JPG destruction

[Tom Deering <tmd@xxxxxxxxxxx>]

>I did not ask you or anyone else to look at your anaglyps.
>I invited you and everybody else to look at my anaglyphs,
>and to comment on them, but you did not. Why not ?

I looked at your analgyphs.  I viewed fiskana4.jpg, moe2ana.jpg, and
moe1ana.jpg at 400%.  There are jpeg artifacts in these images.  You must
use a higher quality setting, or a better compressor.  Photoshop, for
instance, would compress these images flawlessly at the best setting.

>Even with very low compression (PhotoImpact - High quality)
>there are ghosting and other errors, and the files are as big
>as PNG files.

This paragraph sets off alarms in my head.  A PNG is almost always larger
than a JPEG, since PNGs are lossless.  Also, you should not be able to see
artifacts at the highest quality settings.  Different programs use
different methods.  Perhaps PhotoImpact cannot make good JPEGs from your
anaglyphs.

Also, your anaglyphs will be difficult to compress with JPEG due to the
large areas of solid color.  Certainly there would be more room for error
if you were compressing color stereo pairs.

Let me repeat what I said earlier.  A person must use the settings that
create larger, better quality JPEGs for stereo work.  Any artifacts, no
matter how minor, will be visible when you view the image in stereo.
Settings that make medium and low quality images, while perfectly adequate
for 2D, will simply not work in 3D.

I suspect the problem is your PhotoImpact program.  If you send me the PNG
original of your worst looking JPEG, I will recompress it for you with a
different program to see if this is the case.  I would be glad to do this
for anyone else who is having trouble with stereo JPEGs.  You must send a
"lossless" original like a TIFF or PNG--not the bad JPEG.

Cheers,

Tom



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