[CQ] MPC2800 - Color printing with K grays

[mrwho]

Why oh why when I print a color PDF with a color logo and a K gray background, the machine keeps spitting out a CMYK greenish gray background, even though I told the driver that I wanted a black-only gray and I told Adobe that I wanted the machine to manage colors? And it happens the exact same thing on a MPC2051?

[rthonpm]

Re: MPC2800 - Color printing with K grays

Difference in the gamut between CMYK and RGB colour scales? Overall, this is a business colour machine not a graphics box. You may want to try a few things though:

If you have the PostScript option, use that driver.
Run the printer calibrations from User Tools
Have a tech make sure all your firmware is up to snuff

[KenB]

Re: MPC2800 - Color printing with K grays

Is there an RPCS driver for this machine, I don't remember. I can tell you that overall, it's waaaay better at allowing you to use K only.

Also, depending how the graphic is "built", you may be stuck with the 4 color grey.

Beyond that, calibrate the heck out of it to try to get the grey more neutral-looking. Greys will be the first thing to feel the effect of poor calibration.

[Oze]

Re: MPC2800 - Color printing with K grays

The Postscript driver has a setting to use Process Black rather than Greyscale.

[KenB]

Re: MPC2800 - Color printing with K grays

The Postscript driver has a setting to use Process Black rather than Greyscale.

That is, of course, provided the machine has the PostScript option.

[Choro1dal]

Re: MPC2800 - Color printing with K grays

Both the PCL6 and PS3 drivers have the option to print greyscales using K toner only and not a process grey. However there are limitations, particulalry with the PCL6 driver. Installing the ICC profiles will improve reproduction accuracy.

Also checking the RGB or CYMK definitions of the grey in the document will confirm whether or not it is a true grey. The RGB or CMYK values will be the same. ie, R=36,G=36,B=36 would result in a 36% grayscale. If the values were R=35,G=35,B=36 although it would appear to be a grey on-screen it would not be processed as a grey by the print controller.
If you don't have a colour profiling suite, spectrometer or decent graphics package you may not be able to accurately check the grey in the file, Iconinco has a piece of freeware 'Color pick 4.1' which does the job.