Help: How to reduce PDF file size

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Snowflake

New member
Hi :)

I might need some help and I thought of posting about that here because you might know how to do this... I looked up a lot of articles on this matter but unfortunately none of them helped me reduce the size of this PDF file.

I have a PDF File with about 144mb, I made the pages using photoshop. It has some images, but it's not a lot, however the pages size is big (A4 in europe) and the resolution is at 300dpi so that might be where the problem is.

I tried to change the resolution but the pictures lose quality and I don't want that, I just need to resize the file from +100mb to... at least about 10mb max.

Is there a way? Tried to run by adobe acrobat pro to get a smaller file but it changed from 144mb to 136mb... not a lot...

Thanks.
 

tornado

New member
Well there is no one size fits all method. Besides there is not much you can do to reduce the file size that would like asking GTA developers to reduce file size of the game from 60GB to 10GB. 140 MB is not really that much but if you insist:

  1. Use a file convertor to conver the file to a smaller version(this you might have done using Acrobat)
  2. Use one of those Online Compression thingies.
  3. Use less images (this is kind of obvious but...)
  4. Recreate a PDF, with only low DPI text and then add images to retain the DPI of the images.

Apart from that if it is basically for sharing and with tons of redundancies than try 7Zip it might reduce filesize below 100mb but not much.
 

GigaGreg

Moderator
Staff member
Well, unfortunately you have to bear in mind that because of the high quality images, your document will weight more, so you have to decide whether you are looking for low quality (still decent to look) and have small pdf file, or have high quality images and high file size.
 

gigame

New member
Maybe it uses the same principle and algorithm as ilovepdf.com suggested by @"Genesis" above, but I have had good results with https://smallpdf.com/
It can be worth a try.
Another idea would be to first run the images through Riot (http://luci.criosweb.ro/riot/), a small, even portable tool to remove color spectrum information our eyes cannot distinguish. After loading a photo, refuse the resize pop-up (it offers to resize when loading a large image) and test the quality slider at the bottom. Anything above 80% is virtually indistinguishable to my eyes, but it also doesn't reduce a lot of file size. If you slide it back to 60% you will see a significant reduction in file size, but at the cost of some fine details. You have to find a good compromise between image quality and file size. You can also batch process the photos, just drag and drop onto the program (first try with a single image to find the ideal percentage visually checking the results magnifying the images).
Riot.png

(http://www.gigarocket.net/image-host/uo)
In the red circle where you can start noticing some noise in the image at 70%. That is a very zoomed in part of the image, so when viewing fully zoomed out it is almost impossible to see any difference up to 65%, 70%. You can see the original and final size in the purple/blue round squares.

The images treated with Riot maintain the same size. If the original is 1920x1080p the saved image has the same pixel count.
 

Snowflake

New member
Thanks everyone! I think there's no way to resize a PDF without any quality loss, there's always something noticiable.

But from all the links you shared, the one suggested by Genesis was the best that worked for me. There's the one option for less conversion with high quality, still it went from 60MB to 13 MB, a file I tried before the book itself.

So thank you so much for your help!!!
 

GigaGreg

Moderator
Staff member
Closed.

Feel free to open a new topic if you have any questions, issues, suggestions or feedback.
 
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