Pantone Spotcolor Replacement Table LAB

[vansman]

I'm working with Wasatch 6.6 and an Roland CMYK soljet printer.
After printing a few testfile's of an Pantone solid coated guide, i was wondering if i'm using a spot color replacement table in LAB the colors get more accurate.
When i export the original CorelDraw file to PDF with an spot to process setting in RGB the blue and purlpe colors are better as i'm export it to an PDF with spot to process in CMYK. But in CMYK the yellow's are better.
Beside that, in both cases the process yellow keeps a little dirty.

After printing the file in PDF X3 or EPS and replace the color to an LAB value the yellow is much brighter.

What i'm looking for is an XLS or txt file (like the Avery spot color file) wich contains the PMS C name with an LAB value.
This seems to be a good startfile to tweak it myself.
So when Wasatch recognised in PMS named color it replaced it with the right value and it doesn't matter from wich program the file created.

Regards Leon

 

[J Hill Designs]

I was thinking the same thing...good luck, and welcome from cali

 

[rfulford]

I think you are going to see the same results with LAB as you do with RGB. I am not familiar enough with wasatch to advise you on a better method. That is unless wasatch has the ability to recognize the named spot colors. In that case you may be able to provide cmyk replacements for each named color the rip recognizes. At any rate, I have attached a Pantone solid to LAB text file for you to test. I hope it works for you. I made it ProfileMaker and exported it as a tab delimited text file.

 

[rfulford]

attachment

I am not sure it the attachment took. Here it is.

 

[luggnut]

The RIP will still have to translate LAB to CMYK or whatever inkset you are using right? so you would still need the profiles and rendering intents set up

i have read here a lot of people having issues with colors from corel, but there is a lot of people who don't.

 

[vansman]

@rfulford > Thanks for the txt file, i'm gonna test with it.

Wasatch has the ability to recognize the named colors and replace it. (works great to replace color's to match them to Avery vinyls, wich also work with LAB values)

I know that at the end the LAB values are translated to any inkset. (in my case CMYK) But i've also noticed that files in a RGB space have better results against CMYK files. (in my case) even when i'm using different CMYK profiles on export.

I also heard about the pms translation problem with Corel, but i think this can be solved with kownledge and settings

 

[vansman]

First test gives nice result. Colors matches better. But there are a few problems to tackle.
One of them is the handling with spot color below 100% and gradients.
When im testing a pms 259c 100% with an 259 c 50%, the rip also replace the 50% in an 100% covering. So there is no difference between te colors. (Which is logical because the spot color only look at names.)

Because it's not possible to add more then 2000 spotcolors in Wasatch, i can't add al value's from 0 to 100% of each pms color (beside the fact that the table containes almost 100.000 values which become a huge database)

When i'm creating my own file's i could replace all pms in full 100% values. It's only a bit tricky to use this configuration with customer files without analize them.

Hopefully in the future the graphics software creators uses the same values (in Lab) in their engine's for creating export file's. It would help digital printoperators to create an consistent output from different costumers.

 

[Rooster]

Why are you doing the spot to process conversion before you send it to the rip? That's probably the source of the color issue. Sending the spot color as spot should send the RGB or LAB specs to be converted directly to the output profile. Unless you're creating the PDF with the output profile embedded, this should offer better color.

Have you tried creating the PDF as an RGB file and letting wasatch handle all the CMYK conversion? With the new black point compensation (long overdue) it should maximize your gamut to whatever the output profile can handle.

 

[vansman]

Unfortunately Corel can't create PDF with Lab values from PMS. I've tried to create PDF's with RGB output, some colors looks better.
Where can i find th new blackpoint compensation?

 

[Rooster]

Unfortunately Corel can't create PDF with Lab values from PMS. I've tried to create PDF's with RGB output, some colors looks better.
Where can i find th new blackpoint compensation?

It's built into the RIP since v6.4 or v6.5. A version newer than I have unfortunately. It's just part of the way the RIP separates the the files with regards to shadow regions. I'm not sure if it's something you can turn on or off.

It really doesn't matter if the Pantone values are in LAB. As long as Corel doesn't screw up the colors converting them to the RGB input profile. Good luck with that.

 

[rfulford]

Vans, when you did your first RGB test, what profile were you using? Have you looked at eciRGB? How much of a standard is it in your country? I see lower delta E values overall when I compare eciRGB to Adobe RGB.