The new option “gray value tolerance” makes PrPages rather complete. What is the purpose and sense of this value which is also known as "gray balance"?
Because sometimes slightly shading gray colours could be interpreted as very slight light blue or pink color tones for example some main printer-drivers are working with an optionally so called “gray value tolerance” or "gray balance".
PrPages splits each pixel of the pdf-page into the three rgb-values. The “gray value tolerance” represents the difference between the highest and the lowest rgb-value. A value of 15 (by the way
that’s good practice) means that the highest and lowest colour-value (the values are from 0 up to 255) of a pixel can differ at most by the value 15 and still be interpreted as a shade of gray.
Without a tolerance value even the smallest deviation leads to a colour-detection because the slightest difference means that it's not real gray.
Summarized it could be gray or … perhaps a very, very light blue? Anyway not an absolutely clear gray – so there are few coloured pixels on a page and it’s up to you what you want. Some main printer-drivers are working with optionally “gray value tolerances” and if you need identical results
for your work or accounting you should use these option with PrPages, too.