Adding watermark results in unexpected and unreasonable increase in file size.

[ctk785]

I have a 54 page architectural drawing set which I created by printing directly from my CAD application to Acrobat. Each time this drawing set is provided to a third party, I need to add a watermark with a date and title which uniquely identifies the drawing set based on who it was provided to and why. Each page has a title block with a space designated for this watermark. Prior to adding the watermark I spent much time experimenting, testing and optimizing the sequence, settings and processes for creating this document set and I finally feel like I have maximized document quality and file size. Unfortunately, once I add the watermark, the file size is unreasonably increased.

1. The watermark I am adding contains three lines and 46 characters of text using an 8 point font. Prior to adding the watermark, the file size is 5,376 KB. Adding the watermark increases the file size to 6,434 KB, an over 1MB increase! Auditing space usage shows that the increase in contained almost entirely in content streams. The embedded font increase was less than 4KB. Investigating further, I decided to try and add a watermark by typing directly into the text box in the watermark dialog instead of adding from an outside file. To my surprise, this increased the file size to 6,885 KB which is an even bigger increase than adding my own watermark. Still scratching my head, using the same add text from the watermark dialog, I changed the text to a single period. The file size was still increased to 6,872 KB. A 1.5MB increase for a single period!!!

Testing further, I decided to print a 54 page document with only my title block and no other drawings or data. I printed this using the exact same process from the same CAD application as the original drawing set above. The resultant document prior to adding the watermark was 199 KB. Adding my original watermark to all 54 pages of this document increased to file size to 211 KB or a 12 KB increase.

So, to summarize, if I add the watermark to a 54 page document with little content, the file size is increased by 12 KB. If I add the same watermark to a 54 page document with more content, the watermark increases the file size by more than 1 MB!

What the @##$%% is going on!? Every time I think I have Acrobat figured out, it throws me another curve ball.

[Test Screen Name]

After adding the watermark do you do SAVE or SAVE AS?

[ctk785]

I use save as.  I always use save as.  I should have mentioned that in my original post.

[Test Screen Name]

I speculate that something is keeping the original content streams as well as the edited ones. That would account for the increase for files which start with long content streams. No idea what is keeping it or why.

[ctk785]

I have no idea either.  The content stream increases from 2,829 KB on the original doc to 3,895 KB for the watermark file.  By comparison, if I do the same process as above but use "save" as opposed to "save as," the resultant file size is 10,869 KB or roughly double the original size and the content stream is 3,965 KB-close to the "save as" file above. Acrobat can be so frustrating.

[ctk785]

I just did a compare documents analysis on the two files.  Every single page of the watermarked file has 20 plus changes which have nothing to do with the watermark.  All of the changes are marked "this image was replaced" and highlights little bits of text, little sections of vector graphics or little sections of raster images.  None of these changes display any differently that the original document.  I have no idea why Acrobat felt it need to "change" anything.  I expect this is the root of the problem.  The question is: why is Acrobat making changes!!!!?  Should I not be able to add a watermark without Acrobat messing with the rest of the document?

[ctk785]

Upon further testing, it seems that this is not confined to just watermarks. I have discovered that ANY edit to ANY page in this document results in a 1 MB +/- increase in file size. If I delete one letter from one page or add one letter on one page the file size goes up by 1MB.  And no, I don't use Acrobat as an editor, this was just for testing purposes. And yes, I'm using "save as."  I'm sure there is an explanation but I have no idea what's causing this.  I don't normally use watermarks or edit inside Acrobat but this can't be proper behavior can it?

[Alvaro228532500hmt]

I'm having a similar issue, were you able to get anywhere with this?

My work flow is: 

Create PDF document -- add watermark -- save as. 

Then I copy that file over and I update the watermark on the second ocassion. My file size just keeps growing and growing...