View Full Version : Color flow diagram

07-17-2009, 06:35 AM
I think there is a wrong flow shown in the color profi setup schematic diagram:
Black/grey and spot are linked in AFTER output profile - but they are also affected by the output profile?! So the link should go in BEFORE the output profile (as it was shown in CWS4). Bug?

07-21-2009, 01:59 AM
Bug of course not it's a, "feature", eFi don't have bugs.


08-19-2009, 04:43 PM
I understand your confusion. When we designed this screen, we soon realized that no simple arrow layout can represent the precise color processing within the Fiery. There are too many variables, many of them hidden within the user documents, not within the Fiery.

First, for the benefit of others reading this thread, the color flow diagram we are speaking about is available from two areas:
1. Job Properties [select Job Center> select a Job>Properties>Color>”Basic Settings…”]
2. Color Setup [select Device Center>Color Setup>Color Management”]
A similar diagram is available in CWS4. The CWS5 diagram is simpler, mostly because it includes less of the advanced features that were shown by CWS4. Our test users told us they preferred us to remove the advanced features that were making the diagram tangled and never perfectly accurate because of frequent constraints between features.

Now, your question: “Black/grey and spot are linked in AFTER output profile - but they are also affected by the output profile?” Is that a bug? You wrote “So the link should go in BEFORE the output profile”.

For Spot Color Matching:
When spot color matching is ON, “name to CMYK” look-up tables are used to determine the CMYK value corresponding to color names; color management through the output profile is not used. *This is why the arrow is going after the output profile when Spot Color matching is ON.*

Want to test? Go to CWS5: Device Center>Resources>Spot Colors. You will see the CMYK values assigned to color names. Your proposal was to point the arrow before the output profile; it has good arguments for it: the output profile is effectively used to determine the original CMYK values in the look up tables “names to CMYK”. You may also argue that changing the output profile will change the table in use, and it does. But another point of view is represented in the color flow screen, appropriately titled “Color Management”. It is a fact that spot colors do not follow the color management specified by the output profile when spot color matching is ON (making the arrow points after the profile). Here is the test: change the Fiery Spot-On Pantone Yellow and add 100% magenta to it; from now on, printing with the same output profile will print Red with Spot Color Matching ON and will print yellow with Spot Color Matching OFF. When Spot Color Matching OFF is used, an alternate color value is used. This alternate color value is always included with a spot color; it can be in any color space, and it is color managed through the output profile. *This is why the arrow is going before the output profile when Spot Color matching is OFF*.

For Black/Gray:
Gray objects (specified in a job with only gray/black values) bypass color management when the gray and black controls are set. Many times, not always, we want gray objects to be printed using black ink only. Most Fiery are set up by default this way, making the arrow point after the output profile. If every special gray control was set to OFF, including the controls found only in “Expert Settings” (Black text and graphics / Pure Black / Rich Black / Black Overprint”), then I would agree with you that the arrow should point before the output profile. I will review this more carefully. Thanks for your feedback; you are helping us build better products!

04-02-2010, 08:00 PM
So what about percentages of Spot Colors. What math is used to determine the accurate color representation of less than 100% of spot? Does this use spot-on at all, or some crazy math based on the alternate value?

04-06-2010, 08:09 AM
All spot colors are handled within Spot-On. For Pantone Libraries Spot-On will store all the L*a*b* values of the Spot-Colors and will create a unique mapping from these L*a*b* values to the chosen output profile. So each and every time a new output profile is loaded, Spot-On will generate a new L*a*b* mapping of the spot colors to the output profile because each and every output profile is slightly different. This allows the best possible mapping of all the spot colors to the engines gamut capabilities as determined by the profile.

When you are using tints, lets say, an 80% tint, then Spot-On will calculate the 80% L*a*b* value from the L*a*b* of the solid spot color. This goes for all tint values, they are calculated on the fly based on the L*a*b* value of the solid spot color. All these tints, in L*a*b* space, are then uniquely mapped to the given output profile.

If you use Spot-On to edit the solid color, then the tints will also be adjusted accordingly. That is when you edit the solid color, the tints are based on the percentages of the new L*a*b* of the solid color.

Within the Fiery, if you wish to use the alternate color values of the spot tints then you just have to turn Spot Color Matching off.