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Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-20T14:43:37-07:00
by andriv
We have several PDF creating in pantone color. When I convert them to smaller png or jpg files for thumbnail the color looks washed out. Any help is greatly appreciated.

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-20T14:59:57-07:00
by fmw42
post a link to one of your image so others can test. it is hard to know what the problem is without a sample and more information. Also what version of IM and what platform are you using? Also what is your exact command line.

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-21T00:03:44-07:00
by andriv
OK, I have it so that it's not washed out but the color doesn't match close enough. The link of samples is below:

http://dev1.brooks.peeqit.com/samplePantonePDFtoPNG.php

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-21T09:51:40-07:00
by fmw42
both links go to 343C

closest I can come is:

convert BB_343C.pdf -resize 100x100 -profile Profiles/AdobeRGB1998.icc BB_343C_adobergb.png

or

convert BB_343C.pdf -resize 100x100 -profile Profiles/CMYK.icc -profile Profiles/AdobeRGB1998.icc BB_343C_cmyk2adobergb.png


These may or may not be relevant.

http://www.cubbison.com/services/color- ... ained.aspx
http://cias.rit.edu/~gravure/tt/pdf/cm/TT3_1_Vikaas.pdf
http://desktoppub.about.com/cs/color/a/colortools.htm
http://www.laserquipt.com/support/idx/0 ... files.html
http://www.pantone.com/pages/MYP_mypant ... 9567&ca=75

The best way is to display the pdf, use some imaging tool to read its color from the displayed pdf, then create a new swatch.

I am on a Mac and used Pixel Tracker to get the color. Then

convert -size 100x100 xc:"#003D2A" BB_343C_003D21.png

That seems to come out right.

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-22T02:24:44-07:00
by anthony
I would suggest you use a sRGB profile.

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-22T10:19:39-07:00
by fmw42
anthony wrote:I would suggest you use a sRGB profile.
I tried that with poorer result than using AdobeRGB.

Fred

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-23T20:00:59-07:00
by andriv
Thank you for the responses. using the AdobeRGB is what get's it to the closest but client wants it to be closer. I can't just indicate color because the end result is not just a solid pantone color. We have an online application that allows the end user to custom create signage by enter text and images within the companies approved layout (template). The end result is it creates a high resolution PDF for print. The companies approved backgrounds are all pantone colors and as they are customizing it we need to present a preview (png image).

Re: Problem converting PDF using Pantone color to jpg/png

Posted: 2011-05-23T20:06:32-07:00
by fmw42
I am not an expert on Pantones or profiles, but the best I can suggest is to create a custom profile for each Pantone color or do as I said to find the equivalent cmyk color from a display of each pantone color swatch with some application that reads the cmyk colors correctly from a displayed image. Not very good solutions, but the best I can suggest. Perhaps someone more knowledgeable about Pantone colors and IM can suggest something better. Does anyone know of any Pantone to cmyk color conversion software that is open source? Perhaps then the IM developers can utilize that to make better conversions. Is there any existing pantone profile?

I am wondering if this is a problem associated with saving your image as a pdf and the fact that IM uses Ghostscript to convert? Can you create the same image as tiff or png or some other image format and get the right colors or get the right colors when converting that image format to png? Is your PDF storing an image and if so what format is the image that is imbedded in the PDF?