RGB und CMYK komplett verschieden im Publisher

[lacerto]

29 minutes ago, thomaso said:

I am not sure what you mean with "as K100 gives R40 G40 B40 when using ISO Coated 300%". To me K100 gives in this document either RGB 24-23-21 (8-bit) or RGB 9-9-8 (percentage). ... ?

0:51 and 1:04 appear to show the K slider at 100% and RGB values in R40 G40 B40 (8-bit scale). But I might have overlooked something (or perhaps watched the wrong clip!)

36 minutes ago, thomaso said:

This can get respected for swatches easily – but what if you want to check / adjust a certain spot in an RGB image which is placed in an CMYK document?

In most cases these are rounding errors so keeping the lock on and just switching the model gives "accurate enough" conversion value in current profile environment. But grayscale conversions (if using something else than D50/Gamma 2.2; or if using an RGB profile that differs significantly from sRGB), both when actually converting, or checking values, can give highly misleading readings or perform significant inadvertently done conversions just after one switch. 

[thomaso]

1 hour ago, lacerto said:

0:51 and 1:04 appear to show the K slider at 100% and RGB values in R40 G40 B40 (8-bit scale).

Indeed, in the OP's video at 0:51 min for about 2 seconds (the mouse moves around).

Strange deviation from the values I get with this profile (a quite similar RGB value results in 95 K to me) / and a quite different Hue value (157 vs. 49), as if different formulas would calculate on the two computers.

 

[lacerto]

On 9/29/2022 at 1:14 AM, thomaso said:

as if different formulas would calculate on the two computers.

Just different RGB profiles, I suppose. 

But I still do not quite get how Affinity apps handle colors, and especially grayscale conversions. Basically the conversions stay visually "symmetric" whenever the source color can be produced with the destination color space (even if largely different source color values can naturally produce by value if not identical then very similar and at least visually very similar destination colors); after this stage is achieved, conversions in either direction are mostly rounding errors but the color stays essentially "the same". But this does not (necessarily) happen when grayscale values are involved, even when using the default D50 (or Gamma 2.2). The color lock is also confusing because it can produce kinds of confusing display puzzles shown in the clip I posted, hiding the true color values of objects.

InDesign has similar dual color model support for objects without a lock, so it retains both visual and value symmetry between color models as long as values are not manually changed (= even just retyped the same values or touching the sliders), so a mere switch of the model does not actually perform conversions even if the active color mode of the object does change (InDesign creates temporary swatches for ad-hoc color definitions and assigns objects colors by using them). Illustrator (as does Photoshop), on the other hand, has a dedicated document color mode and does not allow conflicting color values so even if colors can be defined in any color model, they are immediately converted to the document color model. This, too, effectively prevents such UI confusions demonstrated in the clip.

Affinity apps basically try to implement the different color handlings of Adobe apps across all three apps (probably because of the common object model and serialization), which then results in these kinds of oddities. But who knows, these things are not documented so we just need keep on guessing.

[thomaso]

33 minutes ago, lacerto said:

But I still do not quite get how Affinity apps handle colors, (…)

InDesign has similar dual color model support for objects without a lock, so it retains both visual and value symmetry between color models as long as values are not manually changed

… if Affinity would at least offer the option to "preserve colour values" it could help at least to maintain colours of defined swatches and colours of image resources with certain swatch definitions, e.g. company logos and other corporate design elements. The absence of this option is one of the points that make Affinity appear not to be as "professional" as it is stated in its technical specifications for handling colour.