CHROMiX

Spot Colours inside/outside gamut

Just wondering if there is a way I can see if a spot colour (or list of spot colours) is inside a gamut or outside?

Can I get a Delta E if it is outside?

Start point would be a spot colour name and Lab* values.

Thanks,

Dan

The easiest way would be to graph the profile in question in 3D (in ColorThink, of course) and create an Lab text file with your spot colours in it and drag the text file onto the 3D graph of your profile and that should show you if the spot colours are within the gamut or outside the gamut of your chosen profile.

Hi Aaron,

thanks for the comment.
Maybe it is the format of my text file, the layout of the information, where I am dragging the file ?
Can you post an example of an Lab* text file that works?
No need for the file, just copy/paste the info here would help.

Thanks,

Dan

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I tried to paste it in here but the formatting gets changed and when I copied from here back into the text file, it no longer worked.

The easiest way to see the necessary format would be to have a look in the Stunt Files directory in the ColorThink directory. For me, this is:
C:\Program Files (x86)\CHROMiX\ColorThinkPro303\Profiles\Stunt Files

In there you should find 2 Lab text files, “Lab Neutral Test - all points.txt” and “Lab Cloud.txt”.

Regarding your question about obtaining a dE figure if the spot colour is out of gamut, it’s not quite that easy. You need 2 points in Lab space to determine the dE between them. One point will be your spot colour but what will be the other point? It could be the nearest hue which is in gamut, it could be the nearest point on the boundary of the gamut, no matter what hue it turns out to be, and so on. So, one needs to decide where the 2nd point, the end of the dE vector will be and if it will be the nearest hue or nearest dE.

Hope that helps mate.

Hi Aaron,

thanks for the pointer, I need to wrap the data up like a CGATS file.

Also understand your comment about Delta E.

Thanks.

Dan

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