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[OM] Re: RAW Bit Depth

Subject: [OM] Re: RAW Bit Depth
From: Doug Smith <dhsmith@xxxxxxxxxxxxxx>
Date: Mon, 9 Apr 2007 20:34:32 -0400
On Mon April 9 2007 6:24 pm, Dan Mitchell wrote:
> AG Schnozz wrote:
> > Remove ONE row of pixels from the edge of the file!  Now the 8x8
> > block of the previous save will not line up with the new save.  The
> > algorithm becomes lossy all over again.
>
>   Oh, definitely -- but I suspect the losses may not be _noticeable_ as
> long as you use a high enough quality setting.

        Out of curiosity I opened a new image in GIMP. The size is 640 pixels 
wide x 
480 pixels high. I then drew 1 pixel wide pure blue horizontal lines across 
the white background at 10 pixel spacing. I saved it a various setting just 
to see what it would do. I was surprised just how terrible it was. I don't 
really understand what all the different parameters actually do, but I found 
that if I turned smoothing off I ended up with very dark lines with odd 
colored lines in the white spaces between, with smoothing on I at least had 
blue lines. 
        I then started a sequence of cropping the bottom line out of the image 
and 
saving the image at a quality of 100. After just 7 iterations of this I was 
surprised just how fuzzy the image was. 
        I know that this might be a highly artificial image but I figure it is 
somewhat representative of tree limbs. If I had a place handy I'd post them.

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