Rich Black and White image on EFI Rip

[lchandra]

Hi,

I'm having trouble printing 4/c black images through the EFI Colorproof XF 3.1.8 Rip. The result that we got has a greenish tint to it. We compare our black and white to an output produced by the FinalProof. I know.. it's apples and oranges, but
Is there a way to make the print pass GRACOL certification and yet produce a 'true' black and white image (on 4/c black)?

Thank you for any advice

- Levy

 

[JDK_Steve]

I'm working on this exact problem today.

My solution to achieve neutral greyscale images was to switch the rendering intent from "relative colorimetric" to "absolute colorimetric".

But now I can't get the proofs to verify, even after a day's worth of optimizing.

I'll let you know how things pan out...

 

[Mike Strickler]

CMYK Blacks in EFI ColorProof XF

CMYK Blacks in EFI ColorProof XF

There should be no great problem in making CMYK blacks neutral in a proof with any good proofing RIP, but certain preliminaries must be attended to. First, the color you're trying to reproduce must itself be truly neutral. Is it? How do you know? Many rich blacks are not. Have you checked by opening the color pricker in Photoshop, entering the CMYK values and looking at the L*a*b* values? the last two values should be 0,0 or reasonably close. Rendering intent will not matter at all on the black, but it it will affect the hue and lightness of grays as it shifts colors differentially toward the paper's white point. Let's assume absolute col. if you're proofing and need to simulate substrate color. Has the printer been properly linearized, profiled, and an optimization run? Do not check select "clean colors" or "Black ink only." Look at your verification results: The hue error (dH) on CMY grays would be .5 or below on a good proof--this is normal and common. Your results are anomalous, so check everything.

Mike Strickler
MSP Graphic Services
Certified Implementer, EFI Proofing Products

 

[comholt]

Levy:

I agree that you should be able to achieve very neutral results with a 4/c black. Mike's Photoshop advice is good. A similar approach would be to create a neutral ramp in PS in Lab mode, then convert to CMYK and send through the RIP. If it prints with a strong cast, you need a new profile. If you don't have in-house profiling ability, I'll be happy to send you a target to print, which you send back to me, and then I can email you a profile.

Steve - we should have phone call or Webex. Spending a day doing optimizations is not the most optimal investment of you time, and since you're already a client we're happy to offer you the help. Sarah will get you my direct number.

 

[Doccolor]

Dear Levy,

Regarding Black and White gray scale. We have a technique for creating a special B&W profile. You can go to our download page Profile_Making_Patches and download our CMYK patches, print them and send them to us. We will create a special profile you can try.

You can also go to black and white digital printing pigment inks and printing technology and read about Black and White printing.

Best wishes,
Scott