Forums / Install & configuration / Unable to create grayscale images (ImageMagick/Debian)

Unable to create grayscale images (ImageMagick/Debian)

Author Message

Christian Johansen

Tuesday 17 July 2007 11:29:06 pm

I have an alias that creates gray scale images. However, it isn't able to create gray scale images from color jpgs... I get this:

/usr/bin/convert '-quality' '75' '-colorspace' 'GRAY' 'input.jpg' 'JPEG:output.jpg', Error: , Return: 1

Which resolves to a "Bogus input colorspace". I searched around a bit, and it seems I am experiencing the exact same bug that was found in eZ Components in december: http://issues.ez.no/IssueView.php?Id=9520&activeItem=36&rv%5B%5D=8&rm=1&column=8&sortOrder=4

I am also using the same Debian package as discussed here (ImageMagick 6.2.4 02/10/07 Q16). It states that the bug is fixed in components, but how about eZ Publish? Is there a workaround?

Christian Johansen

Tuesday 24 July 2007 5:35:12 am

Seems there are several ways to create grayscale images, and colorspace is probably not the one I'm looking for... First: colorspace GRAY seems to work if you do this on the commandline:

convert image.jpg -colorspace GRAY dest.jpg

However, eZ runs it as

convert -colorspace GRAY image.jpg dest.jpg

(paths and quality stripped for clarity). This way of issuing the command yields the "Bogus input colorspace" error as it seems IM is unable to read the colorspace value unless the input image is mentioned before the parameter (???)

Grayscale images can be created by desaturating them or turning up the hue. So I created a filter:

Filters[]=hsb/modulateHS=-modulate %1,%2

That I use as such:

Filters[]=hsb/modulateHS=90;0

...and I have my grayscale thumbnails! Wee! :)

Kim Johansen

Thursday 26 July 2007 4:32:12 am

Hi Christian,

I added a bug about this issue. http://issues.ez.no/IssueView.php?Id=11184

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