In my experience most Laser printers expect to receive RGB data. It’s easy to print a standard test target in RGB and CMYK and evaluate the results, usually the RGB shows smoother prints with better gamut. Sending a black target as you describe is full of things to trip over while trying to maintain a single color black. If sending from Adobe products such as InDesign or Illustrator what are your Appearance of Black Preferences set to? Does it treat all blacks accurately or does it send Rich blacks out? If creating a PDF how are you managing blacks and color conversions, is the pdf even tagged? Many factors can alter your single color blacks before it gets to the printer. Check with the manufacturer, often it can be found on a web site. David Wollmann

On Jan 8, 2020, at 3:47 PM, colorsync-users-request@lists.apple.com wrote:

From: PPS Lists <lists@precisionpixelstudios.com <mailto:lists@precisionpixelstudios.com>>

I used to know how to do this but it has been so long since I have needed to I have forgotten how.

I need to determine if the print pipeline for a certain laser printer is RGB or CMYK. I used to know how to spin up a Photoshop file in a certain way and send to print.

IIRC, the procedure was along the lines of make a CMYK document, and create a black square of equal parts of Cyan, Magenta and Yellow. Then slap a smaller 100% black square on top of the CMY square and send to print. Something like that.

Does anyone know the correct steps?

Thank you.