Wrong color - Manage, Profile or Cal?

[pdan]

Bizhub C6000
IC-413 Embedded Controller
All the Fiery extra's - Colorwise Pro Tools, Profiler, Productivity Package, etc.

I've noticed light grays output are objectionably yellow, far from neutral, far from wysiwyg. (values 7-7-7-7)
This particular job I've cranked the yellow curve waaay down to match neutral; I don't believe in such practice for color control - period.

Why would my highlight area grays be yellow -
I calibrate to the media used before critical jobs.
From Acrobat I have sent Acrobat managed and Printer color managed with identical results. (And tried Acrobat's Emit UCR option.)

I'm about to delve into Profiling, seems to be a daunting task never having done so - In my mind calibrating to stock being run cannot be far off from profiling...correct me as you see fit.

(The job at the moment does use Device RGB images behind cmyk transparency - opacity about 10%)

screen shot shows AA and Fiery Image Viewer with yellow channel correction needed

 

[Schnitzel]

In my mind calibrating to stock being run cannot be far off from profiling...correct me as you see fit.

Calibration is not a replacement for profiling an output device. Printers are not perfectly subtractive devices (as opposed to monitors which can be perfectly additive). Therefore, you cannot characterize a printer using CMYK curves only. You must measure a considerable amount of color combinations to have a good profile.

I cannot help you with your specific problem, but I suggest you profile the printer. This doesn't have to be a daunting task - a profiling session can take half an hour when you are already familiar with the procedure.

 

[pdan]

I gathered together the ES-2000 and it's associated components (Calibration Plate & Backup Board) - hit a wall...

This doesn't have to be a daunting task - a profiling session can take half an hour when you are already familiar with the procedure.

For Cal, I output a Calibration Page - I am not familiar with Profiling...
Is my goal an Output Profile?

 

[gordo]

"Calibration" simply means putting the device into a known condition. After calibration comes "characterization" which is the process of measuring the condition of the calibrated device.

 

[arossetti]

If you are looking at dipping your toes in the water of profiling/color management may I suggest you looking into ASPColourManagement ? They offer a trial, it is all cloud based so no software to purchase - all you need is a spectrophotometer which you should already be using to do your calibration.

 

[pdan]

Thank you to all three with input.
I'm under full service and maintenance, with bundled tools for the task at hand. My tech has me modifying the default profiles...I don't care for eyeball techniques, but it is achieving dramatic improvement over what I (and my quality minded clients) have always considered wonderful color from this machine.
I'll be pressing for their color guy to come in soon.
fwiw, KM in my area has always been top notch attentive to our needs.

 

[Stephen Marsh]

In my experience, “copier” type toner printers can sometimes have linearization issues, they may print great densities above say the 50% mark… However in the 1% to 49% tonal range for each C, M, Y or K toner there can be a lot of variability and you may not get good tones say below the 25% mark. After performing a calibration, print some tint ramps, gradients and all over neutral CMY/K grey full coverage pages at say 25/50/75 tints to see if you have uniform colour balance etc.

Stephen Marsh

 

[F.I.ImGoingFishing]

I see this often when a file is built using both RGB and CMYK Images.
This may be the long way around but works for me.
Open file in Photo Shop being sure that it is in CMYK and resave as a high res .tif.

 

[luv2sled]

you can adjust your printer gamma offset adjustments available in Administrator setting/system setting/expert adjust/quality adjust/printer gamma offset adjust. you can select the screen you are printing which is typically dot 1. Print out the test pattern and there will be a square made up of 64 boxes of cyan/magenta/yellow. The center box should look neutral gray. Adjust the colours cmy until the center box appears neutral gray and then recalibrate your fiery.

 

[tabstogo]

I've been battling this same issue on my C7000 for months as have the techs. My work-arounds included custom tone curves for the files most affected. Not all files were affected and not all areas of a file. At one point three service techs were here working on it at the same time, calibrating (i1sis), replacing parts (developer), calibrating, replacing more parts (lasers), updating, etc. What seems to have resolved the issue, at least so far, it's only been a week, was swapping the hard drives around for the lasers. I believe they switched the Y drive with the C. Of course, then all the files that were already in the machine had those colors switched, but the tech resolved that issue as well after several hours. Have no idea how. So, maybe that will be a path to follow as well. Good luck.

 

[pdan]

@ Stephan Marsh - yep, it's the highlight's -
@ F.I.ImGoingFishing - not with a gun to my head. Possibly the same results, but do yourself a favor going forward and convert to cmyk via Acrobat Preflight
@ luvsled - nice to know. You touched on the Dot choice. As I delved into this I noticed that Dot 1 and Dot 2 have drastic differences in my highlights. That doesn't make sense, at the moment.
@ tabstogo - That's a long dark path. Yes, techs are responsive and willing to resolve issues...there's a lot going on under the hood.

 

[digitalatsigonedotcom]

In many cases, you can assign an .icc profile say from a proofer or press profile, but toner is so much different from ink it won't ever be an exact match. CWS allows you to make curve adjustments on a color-by-color basis, even for Pantones.

 

[KM1791254]

Yellow in process grays

Yellow in process grays

In my experience process grays with a yellow caste can sometimes be resolved by one or more of the following actions.

• Turning off color management on the Fiery, switching CMYK simulation profile to 'Colorwise Off' or 'None'.
• Switching resolution from 1200 to 600 dpi or changing Dot 1 screening to Dot 2/Line 1/Line 2. (Don't forget to recalibrate for the appropriate screen.)
• Turning on 'Image Smoothing' in the Image tab of the job ticket.
• Checking 'Use embedded profile when present' if available.

I'm guessing this has all been covered although the most common cause of this is the job is being color managed twice - just my 2c but hope this helps.

 

[arossetti]

In my experience process grays with a yellow caste can sometimes be resolved by one or more of the following actions.

• Turning off color management on the Fiery, switching CMYK simulation profile to 'Colorwise Off' or 'None'.
• Checking 'Use embedded profile when present' if available.

??? That does not sound right... only if you have color management applied upstream will either of those be considered. But the benefits of doing color management before the DFE would only be a better option in a few workflows.

 

[kurtcron]

I may be off-base with this, but you might want to check your rendering intent and make sure you are not using Absolute Colormetric since that may add a paper simulation (scum dot) into your output. If that doesn't work definitely check the gamma adjustment since it can have a big impact on the highlight dots.

 

[cyanman]

You might also give a look at the Fiery Autogray adjustment. I've been quite pleased with its ability to draw the machine back to neutral. I'm sure that the procedure is available either in the manual or from the CWS help, but you will find the launch button on the lower right of the color profile edit screen. You need a copy glass and the Kodak/Tiffen color charts for this adjustment. In my experience, two iterations of the adjustment work wonders.

 

[pdan]

Follow up -
Everything affects everything.
We went through the gamma adjust to balance the neutrals via Administrator setting/system setting/expert adjust/quality adjust/printer gamma offset adjust (thank you luv2sled)
The results were a moderate improvement. Dot 1 was a good representation of color from the start, but I have had a preference for Dot 2 rendering of smooth shades. After we thought we were done, we took a look at the Administrator setting/system setting/expert adjust/quality adjust/Custom Screen. Dot 2 had been using 133 lpi, Dot 1 190 lpi. Changing the Dot 2 to 190 brought everything into perfection.

Now if I could get this machine to run straight, true perpendicular...3mm spec - maybe for office use...

 

[TekniKal]

mixing rgb and cmyk transparencies can sometimes bring unexpected results, and is not a best practice according to adobe. Have you tried preflight and fix in Acrobat, using color digital printing as the profile? If you are going to adjust the bottom end of the curve just use input of 7 output of 4 for the yellow curve. You could also try using line 1. Your machine has many different screen patterns each with its own advantages.. Dot1 for pictures, line1 for graphics as a rule.

 

[pdan]

Yep, mixed rgb and cmyk interacting with transparency was the root cause.
I've been drinking the rgb and cmyk can co-exist kool-aid.