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monochrome image with grayscale background

Posted: Fri Mar 10, 2017 10:51 pm
by Goreld
Hello everybody,

Could someone tell me what are the specifications behind some kind of pdf that seem to have, for each page, one layer of monochome musical content and one layer of grayscale background (as this one : https://imslp.org/wiki/Special:Imagefro ... 8209/secnp )
I can't find a way to export correctly, in one go, all the images, to treat them in Photoshop to remove the background. How does that type of 2-layer image is called in the pdf world ?
Thanks.

Re: monochrome image with grayscale background

Posted: Sat Mar 11, 2017 5:20 am
by cypressdome
This pdf was generated by the Internet Archive from images (originally in full color) in the jpg2000/jp2 format. In my experience your best bet is to forget about the pdf and go to the source at the Internet Archive. On that page you should see a link entitled "SINGLE PAGE ORIGINAL JP2 TAR." This will give you the original 300dpi images in jp2 format.

Re: monochrome image with grayscale background

Posted: Mon Mar 13, 2017 7:10 am
by coulonnus
Here I am able to split this score into pages with pdftk, convert each page in jpg with imagemagick and then to tif. If you convert directly to tif the greyish background gives random pixels in the background, dramatically increasing the size of the tif.