I am wondering when the black cartridge is used when printing a color page with black in it. Will it only use the black cartridge for text or will it use it for any shade of grey where the RGB values are equal? How about if the RGB colors are very close? Then will it use all color cartridges? I have the 5100cn.

On another note. I've seen some comments on the 5100cn doing a long calibration before each print job. Mine is doing this also and I would like to know if it is possible to configure how often this happens.