CMYK to RGB

[BeckhamStZ]

Hello guys. I'm newbie with Imagemagick.
I want to convert CMYK color to RGB color, but many algorithms which I found doesnt work correctly.
( For example CMYK 0 100 100 0 convert to RGB 255 0 0 but in Adobe Photoshop the RGB Value is not this and also the G and B channels aren't zero )
Is there a way to use Imagemagick to get RGB value of Cmyk color?

[fmw42]

in command line

convert -size 1x1 xc:"cmyk(100,50,25,10)" -colorspace RGB txt:

or

use the color converter at http://www.imagemagick.org/script/color.php

Note: for more exact conversion of a CMYK image to RGB you need to use profiles. see http://www.imagemagick.org/Usage/formats/#profiles

[BeckhamStZ]

I want to use it in php to create text with rgb color from cmyk color. I try with profiles in command line and everything is ok but now in php is not.

Code: Select all

$im = new Imagick();

$im->newImage( 100, 100, new ImagickPixel('cmyk(0,100,100,0)'), 'jpeg');
$im->setImageColorSpace(Imagick::COLORSPACE_CMYK);

header('Content-Type: image/jpeg');
echo $im;

this code make a picture not in cmyk ( its in RGB ) and when I get ImagePixel from x=5 y=5 for example his value is rgb(0,100,100)
Where is the problem ?

[fmw42]

Don't know much about Imagick, but try swapping the order of these two lines

Code: Select all

$im->newImage( 100, 100, new ImagickPixel('cmyk(0,100,100,0)'), 'jpeg');
$im->setImageColorSpace(Imagick::COLORSPACE_CMYK);

Do you know if IMagick allows colors to be specified in CMYK?

[BeckhamStZ]

When swap two lines the result is this ->
Can not process empty Imagick object.

when I add a profiles and call getImageProfiles the returned array is empty.

[cyklop]

Did you found a solution?