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Reducing pdf size

Posted: Fri Jul 22, 2016 6:28 pm
by kosboot
Hi folks,

When I create a score, I use Adobe Acrobat to reduce the file size. But that doesn't give me as much reduction as I see others have done (for example, switching from color to black and white, resampling, etc). Is there some page with a list of instructions on how to reduce file size without sacrificing (too much) quality? Thanks!

Re: Reducing pdf size

Posted: Sat Jul 23, 2016 6:13 am
by coulonnus
Which size do you obtain for 1 page? At 600 dpi a page is about 100 kB big.

Does black an white in your language mean only two possibilities per pixel, i.e. monchrome? Or grayscale?

If monochrome, did you choose the best threshold? Magnify a note head a lot with your viewer. Do you see a compact set of black pixels together? If you see lots of black/white pixels together this increases the amount of information a lot and... the size!

Are you scanning a ca.1900 score or a much older one? Watch it with a magnifying glass. Irregular staff lines, note stems etc. increase the amount of information.

Re: Reducing pdf size

Posted: Sat Jul 23, 2016 6:19 am
by coulonnus
Example of result to be avoided: http://imslp.org/wiki/12_Full_Organ_Pie ... ,_William) Magnify a note head or a beam a lot and you will see what I mean.

Re: Reducing pdf size

Posted: Mon Jul 25, 2016 3:42 pm
by kosboot
I generally scan at 400 dpi but in color because I find the resolution looks better than in any of the black/white options. But, for example, I did a scan, and Cypressdome reduced it greatly: http://imslp.org/wiki/Piano_Sonata_in_B ... ,_Richard) (see under arrangements and transcriptions).

Cypressdome also explained what they did: "Original images: ca.400dpi, color tif (from pdf) files approx. 4000 by 4900 pixels. Editing: re-sampled to 600dpi, converted to black and white tif files, de-skewed, and set uniform margins."

I'm just wondering how to do this.

Re: Reducing pdf size

Posted: Tue Jul 26, 2016 4:40 am
by coulonnus
http://imagemagick.org/script/index.php the non-WYSIWIG and http://www.irfanview.net/ the WYSIWIG. imagemagick is great to do batch-mode jobs. Haven't tried irfanview in batch mode.

Re: Reducing pdf size

Posted: Wed Jul 27, 2016 10:16 pm
by kosboot
Thanks colonnus - I'll give it a try.

Re: Reducing pdf size

Posted: Sun Jul 31, 2016 8:46 am
by coulonnus
kosboot wrote:I generally scan at 400 dpi but in color because I find the resolution looks better than in any of the black/white options.
I concede the result looks more faithful when you print it with colors, but did you consider putting yellowish paper into your printer and printing monochrome scores? :-)

Some scores may have both areas with too light printed notes and areas with too dark a background paper, making a monochrome scan inappropriate, but then grayscale scanning is enough. But I don't think this Wagner arrangement has this case.