View Issue Details

IDProjectCategoryView StatusLast Update
0011432ScribusGraphics / Image Framespublic2013-02-24 19:35
ReporterWelblaud Assigned Tojghali  
PrioritynormalSeverityminorReproducibilityalways
Status closedResolutionduplicate 
PlatformPCOSUbuntuOS Version12.10
Product Version1.5.0svn 
Summary0011432: Duotone – final poor quality
DescriptionThere is a strange difference between previewed image when duotone effect is aplied, and the image in pdf result. Pdf is still correct (tested on Acrobat) pdf/x-1a but the overall image quality with the effect is non satisfying.

in Scribus > looks great
in pdf > looks ugly

CMS is turned ON, icc profile for PC display used.
Steps To ReproduceApply duotone effect to any image (e.g. black and cyan) and export as pdf/x-1a. (Other standards as well.)
TagsNo tags attached.
Patch

Relationships

duplicate of 0004270 confirmed Color management applied before, not after, image effects 

Activities

Welblaud

2013-02-21 14:29

reporter  

scribus_preview_duotone.png (163,785 bytes)   
scribus_preview_duotone.png (163,785 bytes)   

jghali

2013-02-23 12:52

administrator   ~0029882

Duplicate of 0004270.

Image effects are currently applied after color management. When an RGB image is exported to RGB, the effect is applied in RGB colorspace. All is ok. But when an RGB image is exported to CMYK, the image is first converted to CMYK then effect is applied in CMYK colorspace, which can lead to somewhat different result.

In any case, one can not expect RGB to CMYK conversion to systematically preserve colors : the full RGB color range cannot be achieved in CMYK. ICC profiles implement gamut mapping strategy depending on color management settings used. The gamut mapping may in particular not preserve the color luminosity. Try to modify the rendering intent used in color management preferences : "Perceptual" and "Relative colorimetric" is what usually allow to get the best result.

Welblaud

2013-02-24 19:13

reporter   ~0029891

I am sorry but I have changed color space of the picture to cmyk (cmyktool), tried to change Perceptual to Colorimetric and it is still the same :o/

jghali

2013-02-24 19:34

administrator   ~0029893

Last edited: 2013-02-24 19:35

Sorry, but given the nature of the problem converting the image will not avoid the problem : the effects is always computed in RGB colorspace for display after color management has been applied, ie after the image has been converted from cmyk to screen colorspace. This is a known issue which has already been reported as 0004270.

Issue History

Date Modified Username Field Change
2013-02-21 14:28 Welblaud New Issue
2013-02-21 14:28 Welblaud File Added: pdf_preview_duotone.png
2013-02-21 14:28 Welblaud File Deleted: pdf_preview_duotone.png
2013-02-21 14:29 Welblaud File Added: scribus_preview_duotone.png
2013-02-23 12:52 jghali Note Added: 0029882
2013-02-23 12:52 jghali Relationship added duplicate of 0004270
2013-02-23 12:52 jghali Status new => resolved
2013-02-23 12:52 jghali Resolution open => duplicate
2013-02-23 12:52 jghali Assigned To => jghali
2013-02-23 12:53 jghali Status resolved => closed
2013-02-24 19:13 Welblaud Note Added: 0029891
2013-02-24 19:13 Welblaud Status closed => feedback
2013-02-24 19:13 Welblaud Resolution duplicate => reopened
2013-02-24 19:34 jghali Note Added: 0029893
2013-02-24 19:34 jghali Status feedback => resolved
2013-02-24 19:34 jghali Resolution reopened => duplicate
2013-02-24 19:34 jghali Status resolved => closed
2013-02-24 19:35 jghali Note Edited: 0029893
2015-09-17 20:10 Kunda Category Graphics / Image Frames => Graphics/Img Frames
2015-09-17 20:11 Kunda Category Graphics/Img Frames => Graphics / Image Frames