Imagemagick 6.7.7 conversion from rgb pdf to cmyk pdf looks dark

[triveni]

I am using Imagemagick 6.7.7 on ubuntu 14.04.2 ,I am converting a rgb pdf to cmyk pdf it looks dark but it is working fine on Imagemagick 6.6.6. I am using below command.

convert tp_rgb.pdf -verbose -density 300 -colorspace CMYK tp_cmyk.pdf
How can we fix that,can any help me on this.

Thanks

[snibgo]

That is a very old version of IM. I suggest you upgrade. Also upgrade Ghostscript.

At that time, IM was a bit confused about linear and non-linear colorspaces. For that version, one of these might cure the problem:

Code: Select all

convert tp_rgb.pdf -verbose -density 300 -evaluate Pow 2.2 -colorspace CMYK tp_cmyk.pdf

... or ...

Code: Select all

convert tp_rgb.pdf -verbose -density 300 -evaluate Pow 0.454545 -colorspace CMYK tp_cmyk.pdf

[triveni]

yes it seems to be working thanks but still checking..

[fmw42]

IM was undergoing some major changes in the range of 6.7.7 and everything was not worked out until later. See viewtopic.php?f=4&t=21269