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Convert command degrades image Quality

Posted: 2009-11-19T06:37:32-07:00
by manish
Hi Folks,

Currently I am working on some image Manipulation task using ImageMagick.
My task is to convert EPS/JPEG/PSD/AI file to PDF and JPEG. I can able to do this via 'convert' command, but I found that the image quality of output file degrades. I think I am missing some parameter with 'convert' command.

Please suggest me the parameters and its implementation to improve the image quality.

Thanks

Regards
Manish

Re: Convert command degrades image Quality

Posted: 2009-11-19T11:57:59-07:00
by fmw42
Imagemagick is not necessarily a good tool for vector to vector processing. see http://www.imagemagick.org/Usage/formats/#vector

for converting a vector image to a raster image, the best thing is to define the density before reading the image and for highest quality, use a supersampling technique of specifying the density very large and then -resizing down by the same factor. Something like

convert -density 288 image.pdf -resize 25% -quality XX image.jpg

where 288 = 4x72 dpi and XX is the quality setting for jpeg compression

see

http://www.imagemagick.org/script/comma ... hp#density
http://www.imagemagick.org/script/comma ... hp#quality

Re: Convert command degrades image Quality

Posted: 2009-11-20T06:14:10-07:00
by manish
Thanks for reply.

That works fine with the command
convert.exe -density 288 +adjoin D:\Manish\A.psd -density 288 D:\AA.pdf%02d.pdf -flatten D:\AAd.pdf

I have implemented -density 288 as per your suggestion and that works perfect for me.

My next issue is that the source has 11 layers and i found that the PDF file is missing some layers.
Please let me know your suggestion on the issue.

Regards
Manish

Re: Convert command degrades image Quality

Posted: 2009-11-20T10:17:47-07:00
by fmw42
I don't know much about mixing photoshop files with layers with pdf files with pages. I don't think psd files are sensitive to -density upon reading as they are not vector files. Second, I am not sure what you are doing with +adjoin are you separating the layers? In any case, images should be read in before using +adjoin or most other operator functions.

try

convert.exe D:\Manish\A.psd -density 288 D:\AA.pdf%02d.pdf +adjoin -flatten D:\AAd.pdf

I cannot say why you are losing layers.

Note the first frame (layer) of the psd file is generally the flattened image.