Converting spot colors in XMF

[Lab Man]

When I convert spot colors in XMF, I am not getting the same result that I do when using Adobe applications.

A specific example is Pantone 7533 C, a dark brown. The Lab values for this are L25, a6, b12.

The Adobe Lab values and XMF Lab values are identical. They are both using the up to date Pantone Plus Coated library.

My destination ICC CMYK color space is GRACoL 2006 Coated1 v2.

I can convert the Lab spot to CMYK process in either InDesign or Acrobat and get consistent results. I am using Relative Colorimetric intent, BPC on. The CMYK result is 65C 73M 87Y 47K.

In XMF, my source PDF color space is GRACoL 2006 Coated1 v2., and my press output color space is also GRACoL 2006 Coated1 v2. When I convert the color in XMF, the result is 65C 76M 93Y 53K.

When I convert to GRACoL 2013 Uncoated v2, the difference is much more severe. Adobe: 45C 62M 62Y 68K. XMF: 39C 79M 61Y 88K.

It is almost as if XMF is not applying black point compensation. I do not know where that option is for spot colors in XMF.

When I do a GRACoL 2006 conversion using Adobe apps, BPC off, the result is very close to the XMF result. When I do the same for GRACoL uncoated 2013, it is still quite a bit different from XMF.

So to summarize I'd like to know two things. First, is there an option in XMF to turn on BPC for spot colors? (I see it for RGB content, but not for spots).

Second, can I get an XMF conversion that matches an Adobe conversion?

I can repost this in a color management forum if that is a better location, although this issue is very specific to the XMF workflow and Rip.

Thank you.

 

[Tim-Ellis]

Hello,

Now I am no expert on XMF but my first thought was this. Pantone release the Lab values to Adobe for them to apply to their software products and then Adobe change the values. I saw a lecture from a technical sales guy from X-rite and he was bemused as to why Adobe do this.

However, a quick look at the XMF website reveals that:

"Fujifilm XMF is the first commercially available product to integrate the next generation Adobe PDF Print Engine."

So I think you might be right about the black point compensation. However,I wouldn't assume that once you get the numbers looking right, all your problems are going to go away.

 

[Chasfinch]

XMF uses decimal places for the LAB value. I know that can cause a shift itself. doing a little test where the lookup value is exactly what your LAB is then see if it converts.

 

[Danny Whitehead]

Pantone release the Lab values to Adobe for them to apply to their software products and then Adobe change the values.

My impression was that they don't even go that far. Haven't Pantone have added about 400 new spot ink formulas since Adobe last updated their libraries? There have been long debates about this on forums, with Adobe's policy being "we only add what Pantone give us", even though Pantone's EULA says libraries generated by Pantone Color Manager are free to distribute.