Determine if a Printer is RGB or CMYK

[gskibum]

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?

[kevin stohlmeyer]

All printers print in CMYK. What are you trying to determine? What file color space you should be sending?

[Test Screen Name]

If you're in Windows, all non-PostScript printer drivers (even for printers that have PostScript) are RGB.

[TheDigitalDog]

If you're in Windows, all non-PostScript printer drivers (even for printers that have PostScript) are RGB.

And Mac; all GDI and Quickdraw printer drivers expect RGB data. 

[NB, colourmanagement net]

Hi gskibum,

It would be good to know why you ned to know? It helps us answer better.

I'll have a stab anyway:

you wrote:

to determine if the print pipeline for a certain laser printer is RGB or CMYK - - - 

well, firstly are there coloured dots in text?

you wrote:

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.

why not try it?

[but if you do, I'd suggest you use, say, adjacent (not overlaid) 50% grey patches and not black.

Its easier to see the dots and tints in mid grey. It's also easier when making the test image to make the CMYK neutral grey as 4 color because yoyu can use an ICC  profile for that, of course - and that’s fine)

When a CMYK doc gets sent to a printer via an RGB pipeline (e.g. via a quickdraw printer "driver") then its first converted to RGB then back to "printer " CMYK in the driver.

Problem with this is an inability for a user to control the CMYK channels individually and particularly an inability to print pure K - i.e. black as black ink only or grey as black ink only (when that's wanted).

Plainly one particular issue is that black text can be an issue here, its generally undesirable for text to be printed as 4 colour black).

When a K only patch (as in your example) goes to your printer through an RGB driver it generally gets printed with pretty much all the ink colours the printer has on board. SO - looking at the dots of your 4 colour grey and K only grey patches with a magnifying lupe should help you work this out.

If the printer is capable of taking CMYK right through the pipeline (which would generally mean that it has a RIP) then your 2 patches may differ in overall tint, with an RGB driver they may be very close.

But looking with a lupe is the way to check properly. If it’s a CMYK pipeline then the K only grey will have only black dots

I hope this helps

if so, please "like" my reply and if you're OK now, please mark it as "correct", so that others who have similar issues can see the solution

thanks

neil barstow, colourmanagement.net

[please do not use the reply button on a message in the thread, only use the one at the top of the page, to maintain chronological order]

[Blake0D4B]

Hi Neil, do you mean like this? 

[NB, colourmanagement net]

Blake

"Hi Neil, do you mean like this? "

well, yes, IF those files are in CMYK - but do a grey tint patch also 

read all the instructions in my previous message please

I hope this helps neil barstow, colourmanagement net :: adobe forum volunteer google me "neil barstow colourmanagement" for lots of free articles on colour management [please only use the blue reply button at the top of the page, this maintains the original thread title and chronological order of posts]

[Blake0D4B]

Yes the file is in CMYK (Forgra39). The 2 squares I made is how I understood yout previous post. I sent the screenshot because I wanted to get the squares right in Photoshop before I print them...  Are the CMYK ratios correct for each sqaure? what do you mean about additional grey squares? I put the squares Adjacent like you said rather than stacked, what else do I need to do?

[NB, colourmanagement net]

You need addditional patches, one is 50 K

and one is C 50, M50, Y50

Easier to see if an RGB pipeline is adding any colured dots to a 50% K tint.

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer
google me "neil barstow colourmanagement" for lots of free articles on colour management

[NB, colourmanagement net]

Bl;ake, as I wrote earlier in this thread: "

When a K only patch goes to your printer through an RGB driver it generally gets printed with pretty much all the ink colours the printer has on board. SO - looking at the printed dots of your 4 colour grey and K only grey patches with a magnifying lupe should help you work this out.

If the printer is capable of taking CMYK right through the pipeline (which would generally mean that it has a RIP or at the least a Postscript driver) then your K and CMY patches may differ in overall tint, with an RGB driver they may be very close.

But looking with a lupe is the way to check properly. If it’s a CMYK pipeline then the K only grey will have only black dots"

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer
google me "neil barstow colourmanagement" for lots of free articles on colour management