View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0011900 | Scribus | Import / Export | public | 2013-12-23 06:44 | 2016-03-27 11:33 |
| Reporter | christoph_s | Assigned To | fschmid | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | assigned | Resolution | open | ||
| Platform | x86_64 | OS | OpenSUSE 64 Bit | OS Version | 13.1 |
| Product Version | 1.5.0svn | ||||
| Summary | 0011900: XPS Export: CMYK and spot colours are being ignored | ||||
| Description | CMYK and spot colours are currently converted to RGB. | ||||
| Steps To Reproduce | 1) Create two shapes and fill one with a CMYK and the other with a spot colour. 2) Export to XPS. 3) Re-import the XPS into Scribus. --> All colours are in RGB. | ||||
| Tags | XPS | ||||
| Patch | |||||
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Exporting CMYK and spot colors requires referencing colors with ICC profiles with XPS. If this is not a problem for CMYK, with spot colors it is more difficult : - we do not store CIELab values for spot colors - we would need to generate ICC profiles dynamically based on data we don't have (CIELab values) - when mixing spot colors, we would need to predict the result before generating the corresponding ICC profiles, again this would need pretty wild guesses. - the multichannel and named color profiles necessary to support spot colors in XPS have not much support, so xps viewers would be likely unable to open exported file. So basically exporting spot colors in XPS requires knowledge of the printing process a layout software doesn't have. And a basic implementation of the requirements would not bring much better result than an RGB export. |
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Possibly related: The BCS colour palettes offered by dtp studio are in CIE L*a*b*, and making them available for Scribus would probably require full CIE L*a*b* support in Scribus, including colour palettes. Any chance to get this done in 1.6? Or a GSoC project? As to "data we don't have (CIELab values)", how do Adobe products handle this (not for XPS, of course, but their own palettes and profiles)? Profiles are freely available and we could make them an installation dependency for Linux/BSD and link to download locations for other systems. |
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>> As to "data we don't have (CIELab values)", how do Adobe products handle this (not for XPS, of course, but their own palettes and profiles)? There is no uniform rule for Adobe products : Photoshop tends to prefer palettes with CIELab values, InDesign palettes with CMYK values. Afair InDesign may also change its behavior depending on PDF export parameters. But in case of XPS, traditional palette are insufficient anyway for generating data necessary for spot colors support as palettes give values only for 100% shades. As i wrote previously, spot color support in XPS requires knowledge of the print process which is not available to a layout software. Palettes are insufficient and of no help. >> Profiles are freely available and we could make them an installation dependency for Linux/BSD and link to download locations for other systems. The profiles necessary for supporting spot colors in XPS are not provided by anyone. The named color profiles available for Pantone only provide values for the 100% shade and exclude any combination between two spot colors. So they can't be used for XPS. There is no way around : profiles must be generated dynamically. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2013-12-23 06:44 | christoph_s | New Issue | |
| 2013-12-23 06:44 | christoph_s | Status | new => assigned |
| 2013-12-23 06:44 | christoph_s | Assigned To | => fschmid |
| 2013-12-23 10:59 | jghali | Note Added: 0030945 | |
| 2013-12-24 06:35 | christoph_s | Note Added: 0030951 | |
| 2013-12-24 09:25 | jghali | Note Added: 0030952 | |
| 2013-12-24 09:27 | jghali | Note Edited: 0030952 | |
| 2016-03-27 11:33 | Kunda | Tag Attached: XPS |
