Selection by histogram is what you get with Image->Colors->Threshold. You can either do it using a copy of your original image in RGB(A) or, to get really sneaky, you can decompose your image into another colorspace (HSV, for example) and achieve the effect you want by thresholding the appropriate Hue, or Value image, then using the selection on your original image.

You said you wanted to select the colors that were "close to" white. To do this, just use threshold on the value channel and pick up only that part of the histogram that is "close to" white. This will give you a bi-level image from which you can then select the white parts, using the selection on the original image and filling with white (or whatever other color you want).

HTH,

trefftzs@tcsn.net (2002-12-24 at 1531.58 -0800):

You said you wanted to select the colors that were "close to" white. To do this, just use threshold on the value channel and pick up only that part of the histogram that is "close to" white. This will give you a bi-level image from which you can then select the white parts, using the selection on the original image and filling with white (or whatever other color you want).

I would use Levels or Curves to push to white, simpler and smoother results than Threshold and Fill. For other colours, no, but for white, or any colour you can control via channels (directly or decompose & compose back), yes.

GSR