PDF file too large...X Object Forms?

I just encountered this issue for myself last night and found this page as the only search result that had all the important search terms. Here's what worked for me in a situation where my PDF went from about 11 MB to 25.

The main difference I could recall is that I updated a vector file of a Japanese landscape with one of cherry blossoms. The nearly doubling in size was caused by the new .AI file having overly detailed flower artwork, whereas the previous one had simpler shapes.

I exported the .AI file to a JPG and linked to that JPG instead. The PDF became so much smaller, that I was able to go into the compression settings and upgrade the JPG quality for the entire publication and it only grew by a few more megabytes.

Before this step, I visited the larger linked PSDs and exported some of them to JPG but it had zero impact. The bitmap data in them was already rasterized by the time it went to PDF. Vector data carries all the way over into the PDF and the only way to optimize it is to check your .AI and .EPS file sizes to see if they are unusually large compared to what you're seeing rendered. If they are big, then it means there's a lot of vector data that will carry over. Unlike with bitmaps, there is no simple formula for how to reduce the vector complexity and still maintain the wonderful image.

I didn't happen to see one word of advice mentioned. InDesign is notorious for document bloat. Before exporting, I always do a File > Save As. I've seen files drop 20-30MB just by doing this one thing. I don't know how much it affects the PDF size, but I recall it does affect it. At the very least, it's saving a lot of space on your storage location.

I have been quietly following this thread in the background for a while. There are a number of issues here that really need to be discussed.

(1)    The size of a source InDesign file does not necessarily have anything to do with the size of an output file from same, whether that output is PDF, PostScript for printing, ePub, or whatever. The size of a source InDesign file does not take into account any placed content and/or fonts used by text within that source InDesign file. There is absolutely nothing wrong with this.

(2)    You cannot arbitrarily legislate the size of a PDF file exported from InDesign. You can influence the size of such PDF files by virtue of choices made in terms of the export options, but at some point, there is really nothing more you can do.

If a significant amount of the content is placed raster images, you can specify export options that reduce the amount of PDF file size used by such images at the cost of image quality, both in terms of image resolution (by downsampling) and loss of detail (by specifying lossy compression using lower quality settings). Remember that these days, typical monitor resolution is often in the range of 150 to over 300dpi; you can't get away with specifying 72dpi lowest quality JPEG for screen display – in fact high quality screen display may indeed require higher resolution graphics than you might need for office printing!!!

InDesign (properly) always embeds fonts; there is nothing you can do about that and that's a good thing. “Outlining” text to eliminate embedded fonts is totally counterproductive! The space required for all the polygons generated by the outlining take far more file space than the embedded subsetted fonts. Plus, both output quality and rendering (on screen and print) time can suffer dramatically!

Detailed CAD drawings placed as vector (typically PDF or EPS) can indeed be quite bulky in terms of file size (both placed file and contribution to export file size) but converting those to raster images can and most often do turn such content into fuzzy-wuzzy mush in terms of PDF output.

Likewise, both flattening of transparency and converting all colors to CMYK can also significantly increase the size of the output PDF file while simultaneously reducing display and/or print quality and performance.

(3)    Trying to reduce PDF file size “after the fact” in Acrobat is pretty much like shutting the barn door after the horses have escaped. If you are really going to try reducing file size in Acrobat, use the Save as Other=>Optimized PDF instead of the Reduce File Size function. The former gives you granular choice in terms of what is or is not altered or removed. Even then, there is no guarantee that the resultant file will be smaller. (Hint - For some files, removing XMP metadata can provide some file size reduction, depending upon the original content. XMP metadata in raster images from Photoshop, for example, is passed through InDesign to exported PDF.)

(4)    How many of you actually know what a PDF XObject is? There are two flavours of XObjects that might be encountered in export of PDF from InDesign - Image XObject and Forms XObject.

An Image XObject is a definition of a raster image that is defined once in a PDF file but can be referenced any number of times (possibly with different scaling, cropping, and size) at different locations within that same PDF file. Thus, if you place the same raster image in multiple locations in your InDesign file, it is only defined once in the resultant PDF file. (Note that this optimization is used by all Adobe PDF generators including PDF export from InDesign, PDF save from Illustrator, PDF generation from Microsoft Office on Windows using Acrobat's PDFMaker, and even PDF generation via conversion of PostScript to PDF via Acrobat Distiller!)

A Forms XObject is a group of PDF objects including text, vector, and raster images that is defined once in a PDF file but can be referenced any number of times (possibly with different scaling, cropping, and size) at different locations within that same PDF file. (The raster images within a Forms XObject may actually be referencing Image XObjects!) InDesign typically exports a Forms XObject for non-variable content that appears on master pages but is not overridden in any way on the pages based upon same. Thus, if you have a fancy logo, a frame, as well as header and footer information defined on a master page, such content is output once within the PDF file as a Forms XObject and is subsequently referenced by the PDF for each page that was based originally on the master page from which the content was based. (The only other instance of use of Forms XObjects is by some InDesign plugins such as those from XMPie to provide PDF/VT-1 optimization in which case extensive use is made of Forms XObjects.)

Both Image XObjects and Forms XObjects not only can dramatically reduce PDF file size but more importantly can dramatically reduce print time on digital presses supporting PDF/VT!

I know of no situation in my experience where use of either Image XObjects or Forms XObjects did anything negative in terms of resultant PDF file size. Hacks to eliminate use of them are counterproductive at best!! XObjects are your friends.

(5)    EPS - Encapsulated PostScript! I would definitely agree that EPS is a very dated and obsolete file format. It doesn't support ICC color management or live transparency. You should never use it for creation of new content (especially for placement into Microsoft Office documents). That having been said, if you have old content created as EPS from years back and especially if you don't have the original artwork or content from which that artwork or content was derived, other than perhaps making yourself feel good, there is not much if anything to be gained by converting the EPS to PDF (for example) before placing in InDesign. The only exception to this would be if the EPS references fonts that are not embedded in the EPS. You really need to get that problem resolved sooner rather than later, especially if the EPS is referencing non-embedded Type 1 fonts.

Questions?  🙂

I managed to fixed my document. First, you will have to inspect and see your link panel, find out all the vector files... Such as AI, EPS etc... Then using their specific programe and export in PNG or JPEG. Relink all the images and export again... This will get rid of all the X-Object Forms in your pdf making it more compressable. 

I did all these... its a dam tedious process as i am used to export use vector files so that my export is crisp and claer for pront. However, due to COVID-19, print menus is no longer a thing, people use eMenu which is like a pdf online and i have to get it to the smallest file available so loading is fast. Managed to down size a 40mb file into just under 12mb.

Hope it works for you. 

Although this post is one year old, I wonder what you did to reduce the filesize in the end.

I myself figured out kind of workaround for the Xobject forms-problem in this way:

- open the PDF with Acrobat (not the reader).

- save as Powerpoint PPTX

- open the PPTX

- in Powerpoint: Export the PPTX via Acrobat-Tab  "Create PDF". Within this you still can do some settings to reduce quality of images - but maybe this is not necessary, because when you audit the newly created PDF in Acrobat you will find the Xobjects gone. The convert-process made images and other objects out of the Xforms which now are easily reduceable in size.

This worked well for me. I needed the reduced size PDF of a magazine for our reviewers not for printing.

Cheers!

More information and a few screen shots would be helpful to allow us to give you the relevant advice you are looking for.

Is your document full of complex vector art graphics?

Are there placed images? Size? Qty?

What are you exporting? Postcard? 10 foot banner?

Form XObjects are just another kind of page content. They are just named groups of graphical objects within a PDF file.

They are typically (but not only) used for things that appear more than once, to save space.

More info from you will help us define a more specific answer.

Thanks

-Dax