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I have 2 pdf files.

I compared them with WinMerge, BeyondCompare, and even compared their checksums. They are exactly the same to me in every way.

If I open them with Adobe Reader in Xp, and compare them with my bare eyes, they look the same.

But!!! If I open them with Adobe Reader in Win7, and compare them with my bare eyes, they look very different!(particularly border width).

Here are the 2 pdf files I'm talking about:

And here is a screenshot of the 2 files. The one on the right side has thicker border if you look carefully. Remember, they have the same checksum.enter image description here

I would really appreciate it if any clues. Thanks in advance.

share|improve this question
Which version of Reader are you using on each system? – Andrew Cooper Nov 6 '12 at 3:49
Try a different pdf reader. I wonder if acrobat is not remembering some sort of per document view settings, like zoom level or something. – Segfault Nov 6 '12 at 3:58
I tried other pdf reader(PDFXCview) which shows the 2 files are same. I'm using abode reader X 10.1.4. Problem is, I believe the 2 files are same in every bit, yet they look different on the same Adobe reader, how is that even possible? – David Dai Nov 6 '12 at 4:10
Sounds like a font substitution (the font is not available one one of the machines) – soandos Nov 6 '12 at 6:46
screenshot is taken in Win7. if it's font substitution, it should happen on both files. That doesn't explain why they look different. :( – David Dai Nov 6 '12 at 7:01

As Andrew Cooper said, this could be something related to the version of Adobe you are using. If you are still unsure, use MD5 ALGORITHM to generate hash for the files and compare them WITH BARE EYES :p
Hash values don't lie. Even if a single character is different, the entire hash will change. Google AVALANCE EFFECT to know more.
If hashes are same, files are same. Forget the looks as being something related to version

share|improve this answer
I used free commander to generate checksums of the 2 files. And the checksums matched. By that I assume the 2 files are same in every bit, and yet they look different in the same program, how is that possible? – David Dai Nov 6 '12 at 4:09
It maybe because Adobe guys changed the interface to look different. Are you using the same magnification level in both the programs? That could cause the margins to look wide/narrow. If you look at various versions of Adobe, you'll find that UI is quite different. So rest assured, files are the same =) Hash values don't lie – Fasih Khatib Nov 6 '12 at 4:14
they are at the same magnification level. It is not the UI that's different, it is the contents that's different. Thanks anyway :) – David Dai Nov 6 '12 at 5:23
So you're saying if file 1 says WHITE file 2 says BLACK? Plus it'll be great to post screenshots using printscreen. It's easier than downloading plus your data will be safe =) just upload the image you want use community to see – Fasih Khatib Nov 6 '12 at 6:33
The files are identical. While there can be hash collisions in carefully crafted files, both files have the same checksums in both md5sum and sha1sum. – Daniel Beck Nov 6 '12 at 19:38

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