Color change on EPS import V1 vs V2 of designer and Photo (mac version)

[lacerto]

6 minutes ago, Hangman said:

It sounds like a possible mathematical error, I'm not sure whether the conversion goes Lab to RGB, followed by RGB to CMY and then CMY to CMYK but I could see a pretty simple error in the conversion formula being the culprit if that is the case...

 Who knows, but RGB and HSB based spot color definitions get misread in a similar way than Lab based (reset to 50) so my guess is that the code simply just reverts to standard values (edges and midway) whenever reading something that does not "make sense" within expected spectrum.

[lacerto]

Sorry, sadly I made a mistake so no matter how the spot color rendering color is specfied (at least from Corel and Illustrator saved EPS), it will get misread (in app versions and environments where this happens). OP's initial post already showed that this happens also when the spot color is CMYK based. But the tests at least showed that all other modes cause the error, as well.

 

[Hangman]

I’m curious, what was the mistake you made, your previous videos where you exported eps files all seemed to make sense… 🙃

[lacerto]

10 hours ago, Hangman said:

I’m curious, what was the mistake you made,

I created an AI file with multiple PANTONE spot colors from diverse libraries (the intention being using Lab, RGB and CMYK as color modes used to define the rendering color), one of which appeared to be CMYK based, but I mistakenly interpreted a triangle mark as a spot color symbol (which in AI is of course a circle in the middle, and a separate mark). So what I thought was a CMYK based spot color was just a global non-spot CMYK definition in one of the PANTONE libraries, which kinds of colors never have been problematic.

BTW, as a kind of an answer to what I wondered above, whether apps typically or always depend on rendering instructions given in context of spot color descriptions, the answer is no, at least in context of CorelDRAW, which, when referencing PANTONE library colors, asks at file open time, whether a referred library color should be linked to "this or this" PANTONE color library containing the referred swatch name, meaning that it could then be rendered in different ways on screen, depending on which library it was linked to. In context of user-defined spots defined in RGB and HSB (in AI), they seem to be converted to EPS main color mode (e.g. to CMYK or RGB), and e.g. InDesign honors these values, but CorelDRAW does not, though it is not far away, either (it is not "off" but just not accurate so some conversion is involved). As far as spot colors are actually used (as special inks), rendering of course is pretty irrelevant, but in situations spot color information is totally lost (as it is in case of Affinity apps, and currently also in VS), reading correctly the alt color spaces becomes crucial.