CHROMiX

Printer profiling step-by-step

Can anyone recommend a source for step-by-step printer profiling for the noob?

I am trying to profile an EPSON printer using Colorport with an iSis spectrophotometer and MonacoPROFILER.

No problem printing the it8 random target without CMS from PhotoShop.

No problem scanning and saving Monaco session data through Colorport and iSis.

No problem generating a CUSTOM profile through MonacoPROFILER.

I drop the CUSTOM profile in the ColorSync directory and it becomes available in PhotoShop and that is what I use to print a confirmation target.

I then scan the confirmation target and expect it to be reasonably close to the standard but it is not. As a matter of fact the numbers are nearly identical to the first round linearization.

Here is the resulting data from confirmation scan using custom profile:

Average delta E: 30
Average delta E 94: 22
Average delta E CMC: 13

I’m sure I’m missing something.

Thanks for any help…

You had me until you mentioned printing a confirmation target … what are you using as the target? What are you using to check it against a standard? And about that standard - what standard?

Everything you did up until then seemed perfect, but you might be missing some steps between creating the profile of your Epson and trying to dial it (the Epson, not the profile) back to a standard.

Yeah, you see? I did something silly.

What I mean by a confirmation target is I print the same it8 file (again out of PhotoShop) but this time I use the custom profile I generated with Monaco. Now, maybe it’s me but, shouldn’t this second printing of the it8 scan closer to the known values of the it8 GRACoL target? I was expecting the delta E to be a lot closer to adequate.

Thanks, tschroe

Maybe I can answer my own question.

Just like color bars, plate scales, etc. that have been prepared to NOT allow their data to be curved, is it possible the same can be said for this ColorPort generated it8 target?

I will print a known image file and see if it looks like I imagine it should after applying the curve to it.

Thanks for shaking out some cobwebs…

Well, the custom profile you created describes your Epson. Also, the IT8 chart is not associated with GRACoL.

It sounds like what you ideally want is for your Epson to be able to proof (read: simulate) the GRACoL standard - correct? If this is the case, it doesn’t sound like you have incorporated the GRACoL ICC profile anywhere in your chain? Are you using a RIP? What is your procedure in Photoshop?

So many questions … but you’re at least on the right track. : )

…engaging memory banks… …thinking…thinking…

click

Ah. I have it. I know I’ve heard something like this before!

Read this color management myth from one of our newsletters awhile back and see if it pertains to what you’re trying to do: Myth #11: Printing a profiling target is a good way to evaluate a profile.

http://www.colorwiki.com/wiki/Color_Management_Myths_11-15

Ok Patrick, I read myth #11 and understand. This is exactly what I’ve been trying to do so my question is how do I evaluate a profile’s results against the standard? I printed the IT8 target, not managed, a CMYK one, thru my EFI Designer Edition for HP rip on my Z2100 printer, scan it in MeasureTool using my i1 Pro, generate a profile in Profilemaker, and then patched my new profile to the paper type in the rip and printed the target, color managed, with the “new” paper type selected, simulation profile is my regular, customized from G7 dataset, one. Then I measure that target and use Compare in MeasureTool against that same cmyk profile and get deltaE’s of DeltaE 94 average 3.10 and standard deviation 0.83.

I realize while writing this that this must not be right but can’t wrap my head around why right at the moment, hence my question, with these tools I have, how do eval a profile and check it like I see others talking about doing when they say they’ve profiled a printer and got it to a dE of 1.0 or less?

Thanks for any input,
Terry

Hi Terry,

I too have heard others throwing around deltaE numbers in reference to how “good” their printer profiles are. I can’t say for sure without knowing what programs are involved, but generally these numbers refer to some sort of internal consistency check. My guess is that they are doing something akin to a feature we have in ColorThink Pro where you can verify the accuracy of the “proofing” direction of a profile. This can be done in software:
http://www.colorwiki.com/wiki/Evaluate_Profile_Proofing

What can’t be done so easily (but what most people are looking for) is a way to verify the accuracy of the “printing” direction of a profile. As far as I know, there is no way to come up with an easy number to quantify that.