Re: [APML] Scaling Images (was: Cocoon Nebula)

[Jerry Lodriguss <jml@astropix.com>]

>I downloaded the free evaluation version of Genuine Fractals. Using GF I 
>scaled the image down to the exact same size (703x640) as my PS JPG and 
>uploaded it to my web site:


>The pixels patterns resulting from GF are slightly different than 
>Photoshop bicubic. The GF stars are sharper and less smeared. The JPG size 
>of the GF image is larger, which may be an indication that GF preserves 
>more information from the original image.
>
>It is very curious how the image annoyingly shifts around when you toggle 
>between the two. Could PS or GF be screwing up its scaling?




Hi Matt,

I'm trying to understand exactly what you did here.

You took an original uncompressed full-sized image and you ran Genuine 
Fractals on it to compress it. Did you use the lossey or lossless 
compression in GF?

Then you downsized it in GF, and you JPEG compressed it? So which image is 
that on your web page the img_on or img_off?

You also took the original uncompressed full-sized image, and downsized it 
in PS, and Jpeg compressed it?

Then you compared both as PS JPEGS?

This sounds crazy to me. <G> The comparison should have been using both 
just resized and not compressed the final time. The GF image was already 
compressed once, then re-sized, and then compressed again (the final time 
with Jpeg).

To my understanding, Genuine Fractals is mainly for enlarging images larger 
than the original file size.

As for enlarging images with GF, I've done several comparisons between GF 
and Photoshop's interpolation when increasing the file size of an image, 
and I don't see where GF is any better at all.  I think Chuck has reached 
the same conclusions from some tests he did with Lightjet prints.

GF is supposed to work better with images that contain fractal patterns in 
them, such as nature shots with trees. I have heard that GF does work 
better than PS with extreme enlargements, like blowing up a 35mm original 
to the size of a billboard, and if I ever need to do this, I'll keep GF in 
mind. <G>

Jerry





Save your money and don't get GF.  Do some comparisons on enlarging an 
original non-compressed file both with GF and Photoshop.
Astrophotography, Tips and Techniques
for Digital Enhancement in Photoshop:
http://www.astropix.com

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