Wrong sRGB -> CMYK conversion ?

[idealprod]

When i'm trying to convert the same image with Photoshop : everything is perfect.

What i do wrong ?

Thank you.

Best regards,
François

[snibgo]

Please upload your test-rgb.jpg to somewhere like dropbox.com and paste the URL here.

Conversions between sRGB and CMYK should generally use profiles. If test-rgb.jpg has an embedded profile, it should certainly be done with profiles.

[idealprod]

Thank Snibgo for your answer !

Here is test-rgb.jpg file :

http://demo.ideal-lab.com/test-rgb.jpg

And i'm trying to apply CMYK profile like that :
convert test-rgb.jpg -colorspace cmyk -profile profil-cmyk.icc test-cmyk.jpg

But the result is them same (bad colors)

Thank you for your help.

Best regards,
François

[snibgo]

Your command converts the sRGB image to CMYK using simple arithmethic, then assigns a colour profile. The assignment says the image has been encoded with that profile, but that is not true.

Instead, I suggest you assign an sRGB profile, then convert to the CMYK profile.

Code: Select all

convert test-rgb.jpg -profile sRGB.icc -profile USWebCoatedSWOP.icc c.jpg

... but use the appropriate CMYK icc file for your printer.

You might want "-intent Perceptual" or some other setting before the profiles.

[idealprod]

Thank you so much Snibgo : SRGB -> CMYK conversion is now perfect !

Best regards,
François.