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Color rendering wrong when mixing vector and pixel


NotMyFault

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Hi,

It seems vector objects and pixel layers get wrong colors if color panel is using a color format not matching document format.

Example shows a RGB document with a rectangle with stroke above a pixel layer.

when cycling through color models, CMYK and GREY render wrong.

Similar, after converting document to CMYK, RGB color render wrong whereas CMYK renders correct.

Someone should try all possible combinations.

steps to reproduce

  1. Photo or Designer, create new document in RGB/8
  2. add pixel layer
  3. add rectangle. Set fill to transparent. Set stroke to black. Set stroke width large, to be visible
  4. select both layers
  5. use color panel / Studio to change colors. Use CMYK colors

alternatively, create CYMK document (or convert test document) and use RGB or HSL colors.

 

 

Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080

LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5

iPad Air Gen 5 (2022) A2589

Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps.

 

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  • 1 month later...

Just found out issue affects V1, too. This is really bad. All vector bitmap brushes / fills and similar objects with colours selected in colour panel/studio in non-matching colour formats are wrong.

In Addition, coluor panel and info panel use different methods to convert RGB/CMYK. This is colour roulette.

Ouch. 

Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080

LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5

iPad Air Gen 5 (2022) A2589

Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps.

 

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1 hour ago, NotMyFault said:

All vector objects with colors selected in color panel/studio in non-matching color formats are wrong.

No, vector objects are being coloured correctly while simultaneously selected Pixel objects are being wrongly filled with a naive non-colour managed conversion from the Colour panel colour model to the document colour model. The Pixel objects should be, but are not, filled with a colour managed conversion from the relevant latent colour profile of the document to the manifest colour profile of the document.

So, yes there's a bug, but it's not what you thought it to be.

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Following on from my previous comment, this message is primarily for the developers.

This thread is in an iPad forum but the problem also affects Affinity apps on macOS, and has  been carried from Affinity 1.x to 2.x.

 

Recipe: simultaneously select a vector object and Pixel object in an RGB document. Adjust fill/primary or stroke/secondary colour with Colour panel in CMYK mode instead of RGB mode.

Expected result: the vector object and Pixel object should have matching colour in the document view. That is because:

  • the vector object should have the CMYK colour definition (which will be displayed following colour managed transforms from the document's latent CMYK profile to the document's manifest RGB profile and then to the system's display profile)
  • the Pixel object should be filled with a colour managed transform of the specified CMYK colour from the document's latent CMYK profile to the document's manifest RGB profile (and will be displayed after a further colour managed transform to the system's display profile)

Actual result: the vector object and Pixel object have different colours in the document view. That is because:

  •  the vector object does get the CMYK colour definition
  • the Pixel object gets filled with a naive non-colour managed conversion from the Colour panel colour model to the document colour model.

 

In my opinion, the lack of colour management in the filling of the Pixel object is a bug.

If we use the Fill command to fill a Pixel object with a CMYK colour in an RGB document, there is a colour managed transform from CMYK to the RGB that is actually put in the pixels. Similarly, If we use a brush to paint a CMYK colour in an RGB document, there is a colour managed transform from CMYK to the RGB that is actually used to modify the pixels.

Logically, there should be the same colour management in the "simultaneously selected" situation described above.

Yes, we should be specifying RGB colours in an RGB document to get accuracy, but I think colour management should be applied consistently when we do specify colours with colour models which differ from the document colour model.

 

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  • 9 months later...

This has been fixed for iPad in some of the later V2 versions.

Info Panel for Desktop is a different topic.

 

Mac mini M1 A2348 | Windows 10 - AMD Ryzen 9 5900x - 32 GB RAM - Nvidia GTX 1080

LG34WK950U-W, calibrated to DCI-P3 with LG Calibration Studio / Spider 5

iPad Air Gen 5 (2022) A2589

Special interest into procedural texture filter, edit alpha channel, RGB/16 and RGB/32 color formats, stacking, finding root causes for misbehaving files, finding creative solutions for unsolvable tasks, finding bugs in Apps.

 

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