I've been using irfanview for several years. Very good software.

One thing I use often is "Image>Replace Color". I know how to set my replace and new colors. One value that has puzzled me is the tolerance value. Colors have a Red, Blue and Green value. Am I assuming correctly that the tolerance value is "applied" to ALL the original red, green and blue values?

If I have an image with black text and a mostly white background (255, 255, 255) but there are some very light gray blocks of colors scattered throughout (for example: 253, 253, 253), would a tolerance of 3 change the gray blocks to white? In other words, how should I correlate the 1-128 tolerance value to the 255, 255, 255 values? Since the black text has some shades of gray at the edges of the text, I do not want to set the tolerance too high or else the text becomes too blocky.

The grays might not be too visible, but I know they are there and they occasionally cause problems when I use an image in another programs.

Thanks - David