Sven Neumann <[EMAIL PROTECTED]> wrote:
> Steve Litt <[EMAIL PROTECTED]> writes:
> > By the way -- I use select by color a lot when I scan yellow
> > receipts. I use select by color to turn the yellow to white, then
> > save it as grayscale and save mucho megabytes.
> The classic method to make the paper on a scan to appear as white is
> to use the Levels tool. Use the white-point color picker and click on
> an empty spot of the scan. Or, even better, define the white-point
> before doing the actual scan. Most scan software (including XSane)
> supports this operation.
That has a quite different effect from what Steve mentioned.
Adjusting the white point will scale all the colours in the image.
For example if you had green writing on yellow paper, adjusting the
white point like this would change the green to cyan (and red to
magenta, but not affect any blue writing).
Mind you, for Steve's receipts and his use of them, the final result
in B&W might be OK.
Adjusting the white point is a very useful technique for colours
_within_ an image, but it's a bit flawed as a general method for
rendering the surrounding paper as white (unless the ink is pure
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