Luminous Landscape Forum

Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: tived on May 06, 2009, 12:31:22 am

Title: CMYK ink density
Post by: tived on May 06, 2009, 12:31:22 am

How do I translate this into a black point when preparing RGB images to CMYK
The ink density is C 1.00-1.20 M 0.90 -1.10 Y 0.73 - 0.90 K 1.10 -1.40.
Color space ISO uncoated (Fogra29L).

I thought I had gotten my head around it all, but now, I think I need a refresher

thanks for your help

Henrik

Title: CMYK ink density
Post by: neil snape on May 06, 2009, 03:07:53 am

Quote from: tived

How do I translate this into a black point when preparing RGB images to CMYK
The ink density is C 1.00-1.20 M 0.90 -1.10 Y 0.73 - 0.90 K 1.10 -1.40.
Color space ISO uncoated (Fogra29L).

I thought I had gotten my head around it all, but now, I think I need a refresher

thanks for your help

Henrik

Well you don't have to. If you are trying to proof convert the rgb to the Fogra profile with either perceptual or relative then print with relative and no BPC for your inkjet profile.  The ICC profile will place the black point at it's maximum which is absolute values from measured data on a Fogra press sheet (averaged).

Best use a paper that closely fits in with the Fogra uncoated paper though.

Title: CMYK ink density
Post by: tived on May 06, 2009, 04:29:30 am

Thanks Neil,

I am just worried that the shadows will block up, this is being printed in Hong Kong and I am in Perth, Western Australia, so there won't be an actual press check
how can I best control the situation?

Henrik

Title: CMYK ink density
Post by: Czornyj on May 06, 2009, 04:59:42 am

Quote from: neil snape

Well you don't have to. If you are trying to proof convert the rgb to the Fogra profile with either perceptual or relative then print with relative and no BPC for your inkjet profile.  The ICC profile will place the black point at it's maximum which is absolute values from measured data on a Fogra press sheet (averaged).

Best use a paper that closely fits in with the Fogra uncoated paper though.

Neil - wouldn't it work if we could take some profiled proofing paper and print the FOGRA29 converted CMYK image with absolute colorimetric rendering intent in Photoshop?

Title: CMYK ink density
Post by: neil snape on May 06, 2009, 09:26:51 am

Quote from: Czornyj

Neil - wouldn't it work if we could take some profiled proofing paper and print the FOGRA29 converted CMYK image with absolute colorimetric rendering intent in Photoshop?

Both absolute and relative use the same black mapping , only the absolute paper white is included in absolute rendering. With inkjets the cross proofing with absolute trying to mimic the paper white rarely works.

The best proofing on inkjets is and always has been use a paper with a near character of the actual press paper, then run CMYK source embedded profiles through relative to a custom profile BUT you need to uncheck BPC.

You won't be able to use a glossy paper for example and absolute and expect the results to be reliable. On the other hand using a matte or semi matte  proofing paper, and relative and your proofs should be looking good. You can measure the Fogra Media Wedge strip and measure them into measure tool and compare the measured strip to the Fogra averaged data to have a dE report.

Title: CMYK ink density
Post by: tived on May 06, 2009, 10:34:06 am

Hi Neil,

"You can measure the Fogra Media Wedge strip and measure them into measure tool and compare the measured strip to the Fogra averaged data to have a dE report."

I am not sure how to do this, I usually use a crude method, and print the numbers on a grayscale stepwedge to determine first separation in the blacks and use that?

Henrik