QUOTE(Blade21292 @ Apr 20 2007, 10:40 AM) [snapback]19296[/snapback]
Is there a place to go where they tell you how to fix your scanner levels?
I did this to Laurie's JPG in "The GIMP". Open the file, choose "Tools | Color Tools | Levels... " and then press the "Auto" button in the Levels dialog, then save the image. But you can do the same in virtually any photo editing program. Find a button labeled "Enhance" or something like that, and it's going to do the same thing.
Imagine a histogram of the greys used in the image. Along the X-axis are the various colors used in the image, from pure black to pure white. The Y axis represents how many pixels are that color. A large value means that color is used a lot in the image, while a short one means it isn't.
Then in general, a washed-out looking image is going to have a flat tail on one end or the other, often just on the dark end. The "tail" represents colors that aren't used at all -- i.e., in Laurie's case, there are no very dark darks in the scan.
What "Auto Levels" does is "chop off the tails" and spread the histogram out. It makes the darkest greys darker, and the lightest lights white (if there's a tail on the light end.)
If you are so inclined, and have a program like The GIMP or Photoshop which gives you more control, then you can edit the histogram yourself, removing just one tail, for example, or modifying the mapping from picture greys to the final image. In fact, some scanner drivers give you this capability as well, in the "Advanced settings" dialog, but I find it easier to do it on the finished image -- you get the same result and it's easier to customize.
Finally, note that one personal goal I've had with my art recently -- and it's served me well -- is to draw so that "Auto Levels" has no visible effect -- i.e., so that your pictures don't have any "tails" at all. That means you're using the darkest blacks and the whitest highlights you can. It's a goal to strive for, not necessarily achievable if your scanner is imperfect, but worthwhile in any case. It definitely has made a positive difference in my art.