CHROMiX

Epson 10600 Ultrachrome Ink Profiling Question

(Run by a Wasatch RIP)

This is the set-up that we use for contract proofs for our presses.
For the linearization of the proofer I use the following numbers, (borrowed from a SWOP certification sheet for an Epson 9600 Ultrachrome ink with a different RIP)

C=1.15, M=1.36, Y=.84, K=1.38

From here I can get a great looking linerization chart. print an ECI and make a profile(gretag). The proof however does not come out good.

Am I missing something here or does somebody have any insight on this?

Thanks,
Captain

The SWOP spec is C=1.3, M=1.4, Y=1.0, K=1.6-1.7.

You should not be adjusting solid ink density to acheive a linear ramp. Set your solid densities at SWOP (if possible) and then adjust your gain curve to acheive linear. Your “intended” output should be SWOP.

Also, make sure that your presses are printing to SWOP. If they’re not, you’ll have to create a Press Profile to set your “intended” output to.

The SWOP spec is C=1.3, M=1.4, Y=1.0, K=1.6-1.7

From my understanding this is the density set for press not for digital proofers. The reason I looked up the density for my printer and inks was because without adjusting densities the final proof was very yellow even with a SWOP output profile. When I started to look at the similiar printer/inks/similar paper with different RIPs I noticed that on the certification sheets for SWOP they were running these other densities.

(Epson9600/BestColor C=1.2, M=1.46, Y=.97, K=1.47)
(Epson9600/Efi Colorproof C=1.15, M=1.36, Y=.84, K=1.38 )

My knowledge is limited and not even sure if I am asking the right questions…
Should I be concentrating on other aspects of the proof more (TVI, PC, etc.)

Is anyone running an Epson 10600 with success as a contract proofer? :open_mouth:

Inkjet inks are not necessarily formulated to match SWOP, therefore if you just looking at density (or TVI/PC, which are density based) it doesn’t ensure a match. You could potentially hit density and dotgain for SWOP right on the money with your inkjet and have a poor vusual match. A better method might attempt to match a target colorimetrically using Lab, as a GMG Rip does. I don’t have any experience with the Wasatch Rip. How are you implementing your profiles?

We’ve been running GMG driven Epson printers (76/9600/4000) for some time as contract proofers with great success.

Oops! Missed the device name… I saw “RIP” and assumed it was a real proofer.

I’ll read a little more closely next time!

“You could potentially hit density and dotgain for SWOP right on the money with your inkjet and have a poor vusual match”

Yeah…I found that out the hard way!!!

So since my proofer/Rip setup is not SWOP certified should I use these numbers that should be close to my set-up as a base-line?

As for my profile set-up…printer profile is my created epson profile and CMYK input profile if SWOP or GraCol. This is the way that Wasatch sets it up…

Maybe I am creating my profiles wrong with regards to UCR, GCR, black point start, etc.? I am using Gretag software and hardware.

“A better method might attempt to match a target colorimetrically using Lab, as a GMG Rip does.”

I overlooked this. Can I do this in Gretag while making a profile or does it have to be on the RIP. Not sure is wasatch has this capability.

At 10:51 AM -0700 6/28/05, Captain wrote:

“You could potentially hit density and dotgain for SWOP right on the money with your inkjet and have a poor vusual match”

Yeah…I found that out the hard way!!!

So since my proofer/Rip setup is not SWOP certified should I use these numbers that should be close to my set-up as a base-line?

As for my profile set-up…printer profile is my created epson profile and CMYK input profile if SWOP or GraCol. This is the way that Wasatch sets it up…

Maybe I am creating my profiles wrong with regards to UCR, GCR, black point start, etc.? I am using Gretag software and hardware.

the density values that you are seeing from the inkjet bear very little resemblance to those on press.

It is also pretty much a myth that the density values on inkjet should match those on press.

It seems like they should but the ink colors on the inkjet are different enough from press inks that they don’t match up with the filters in a densitometer the same way and so they don’t mean the same thing (similar numbers may look quite different)

For effective RIP setup you should set your channel end-points so that the resulting gamut is larger than that of the press you are trying to simulate but not too much larger. While it is tempting to try to get all the gamut possible from an inkjet, the edges of the gamut can be pretty weird due to inkjet ink behavior.

So,

  • set effective end points
  • Linearize
  • then build a good inkjet profile
  • test press->inkjet transform in Photoshop (don’t try the RIP’s color conversion until you know the profiles are good)
  • then move profiles to RIP and try transform there

density is effective for control on press. It rarely has a role to play in proofing on inkjets.

Regards,

Steve


o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX


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