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I am creating figures for a scientific paper. The journal I am submitting to seems confident "all figures can easily be reduced to less than 50kB each (gzipped) without significant loss of quality". One figure I am starting with in photoshop PDF format is ~30MB. I cannot comprehend how I am possibly going to reduce this down to ~50KB without significant loss, but perhaps there is a way?

My image has text, symbols, colour charts and sharp lines that represent functions. I include a screenshot of the image below, and a dropbox link to the actual file just in case that is helpful: https://www.dropbox.com/s/m3p6j6fmccnfvgw/figure2.pdf?dl=0

Any help greatly appreciated :)

  • Wow if this is possible it would be amazing!! – Timothy Nov 27 '14 at 1:08
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    Tom, what did you make the original file in? A graphics program or some sort of math application? You need to create it in something that can handle vectors and save it as something like an .eps file. Then bring that .eps file into InDesign to add all of the text labels / legends. Right now its all raster which is why its enormous. – Ryan Nov 27 '14 at 3:04
  • I made the plots in Mathematica (a math application) then imported into photoshop. Some of the axes labels (theta, phi etc) are screenshots and the a,b,c,d,e circles were copied and pasted from powerpoint. – Tom Nov 27 '14 at 11:26
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    You should have dobe all your styling in mathematixa and exported as eps (postscript) And they would have been significantly smaller. Probably near yoyr target range. – joojaa Nov 27 '14 at 15:42
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    Thanks all for the suggestions. I know better now how to produce figures in the future. Fortunately I was able to get a reasonable image by exporting to PNG-8 and reducing the overall pixel dimensions, which gave a file size of about 1.5MB. Also in the end I found out that the ~50KB limit was a hangover from the 90's and they do accept much larger files than this! – Tom Nov 27 '14 at 19:35
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A ~620% file size reduction is asking a great deal.

It's possible, but I'm not sure what restrictions should be watched, file dimensions? color depth? etc.

enter image description here

^^50k gif file.

This is a reduction of the dimensions by 85%, set as a gif with only 32 colors in the color table.

enter image description here

As @Ryan points out, if the text and labels were vector in nature it may allow file reduction without dimension reduction. Another possible alternative is to forego gradients if possible in favor of solid colors.

  • How did you manage to get dithered colors in your color table? That sort of circumvents its intended use... – usr2564301 Nov 27 '14 at 11:01
  • How on earth do you calculate the reduction rato? – joojaa Nov 27 '14 at 12:57
  • The restrictions are that final image needs to be of file type JPEG, PNG, GIF or PostScript. It is perhaps possible for me to redo the axes labels, symbols and the letters in the circles in some other format that makes them more compressible. At the minute they are copied and pasted from powerpoint or screenshots – Tom Nov 27 '14 at 15:04
  • @joojaa (I'm an artist not a math major but...) [1024*30]/50 = 614.4 – Scott Nov 28 '14 at 4:46
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    point being reduction of over 100% would mean you created space on disk. – joojaa Nov 28 '14 at 4:59
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Use mozjpeg for quality coding.

What resolution do you need it in? I made the image come down to 170kB using mozjpeg's algorithm (40% quality). It's visibly OK.

Using PNG-8 (100% quality), I got the filesize down to ~600kB

Another alternative - use tinyjpg.com and it'll reduce the jpg down to ~300k but with a very little visual quality loss (you'll be hard pressed to see a difference unless you zoom in).

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