Export same pdf from indesign twice, different size on disk.

[bianca-mariab50444613]

Let me bring some details. I have 2 tiffs worked in photoshop and flatened. Dragged them into indesign and exported as pdf with a custom preset twice, but the first export was some days ago.. and the second today. SAME settings.. nothing changed... but the first one is bigger than the second with 110kb. why?

I have acrobat 9 pro extended (9.0.0) and indesign 2014 (10.0.0.70) and Win 10 x64.

[Cari Jansen]

I'm thinking that depending on the compression used for images, there might be a level of randomness in that. E.g. during the PDF export JPG compression might be applied to an image? I'm not sure if that's always performing the exact same compression and change of pixel colours (which is what JPG does)... that could possibly explain a subtle difference.

Also:

• Did you by any chance edit the TIFFs at all? even though their physical dimension is identical, just a subtle change in colour could explain change in file size when converting to PDF through InDesign.

If file size is critical, you might want to try some other approaches as well:

• Open the images in Photoshop and choose File > Save As, and set Format/Save As Type to Photoshop PDF
• Or Open Acrobat and choose File > Create PDF from File, and navigate to the TIFF files.