Reducing file size

[lizzarddesign]

Please help!  I have tried everything to reduce my file size in indesign and acrobat and can't seem to get it down low enough.  My original indesign document was about 200MB and the person requesting it wants it at 2MB or less.  I have tried save as and reduce file size in indesign and save as and optimizing in acrobat.  Optimizing too far makes the quality of some of the images horrible and doing all of these combined only gets it down to about 6MB.  How do I reduce the file so that it is 2MB or less???!!!

[Jongware]

That lower limit set by your client limits your options. Good images -> large file, bad images -> small file. You can't have both, you have to pick one of these.

(A similar choice which I'm facing almost daily is "Good, Cheap, or Fast: pick two out of three and forget about the remaining one".)

[lizzarddesign]

i was hoping there was a way to get it down without getting extremely pixelated.  i think there is a way to reduce the file size per picture/file that I have placed into indesign, therefore reducing the overall file size, how would I go about doing that?  i was hoping there would be a way around it to save time but it seems not...

[Guest]

Are there any transparencies on the pages

Have you cropped & resized the photos to size used in indesign.

[lizzarddesign]

when i go to acrobat-advanced-pdf optimizer-audit space usage it says most percentage is images and content streams.  there are some transparences but not much...  Yes, I place the images I want into indesign and then resize them to fit the layout.  most of them are very large and I have to scale them down.  is this why I can't reduce the file size to the required 2MB or less?  I don't understand why I can get it from 200MB to 6MB but not down to 2MB. 

I found this advice online (below) but when I did it to some of the images in photoshop, it didn't change their jpg file size.

"Open your file in Photoshop, choose Image > Image Size, turn off the Resample Image checkbox (if you don’t want the image data to change), then set the resolution to something reasonable (such as 225 or 250 ppi). Now save the file and reimport it into InDesign. InDesign places the image at the proper size, makes a much smaller proxy image, and the next time you do a Save As, your file size should drop considerably."

[Guest]

Transparencies can add a lot of size to a pdf, The only way I have found to fix this so far (and still open for suggestions) is to copy the photos that have transparencies ie the photo and the effect into photoshop flatern it and then save it as a tif or jpg. As per this discussion http://forums.adobe.com/thread/966926

Got my 6mb pdf down to 1.6mb pdf

Size all photos in photoshop to the widith you need and crop them as well

[lizzarddesign]

should i constrain proportions and/or resample image in photoshop when changing the image size?

[Guest]

I believe when you output to pdf the export will trim the photo to the size you have on the job at least there is an option there that does that, not sure what difference actual size of the image makes to the size of the pdf.

Transparencies are a big space waster, if you can flatten them in photoshop it will reduce the size of the PDF a lot as per my 6mb file down to 1.6mb file

[Rik_Ramsay]

As has been mentioned above by a few people, having the images imported at final size (or close to) will help a lot with the InD file size which then translates into the PDF when you come to export. Its much easier to compress a 4mb image to 1mb than try and compress a 20mb to 1mb without changing the size (or losing a LOT of quality).

If this is not going to print, have the images at 150dpi (or less). Constrain proportions just means it keeps the same ratio of width to height, so in most cases you would keep this checked.

In addition to cleaning up the styles, removing any unused swatches can also help reduce the size of both InD and PDF files.

Not sure if InDesign does it but when you export PDFs from illustrator after masking the images, the PDF still contains ALL of the image. That's why if your trying to keep to a small filesize, it's best to bring the images in at the size required.

[Guest]

In the compression setting in the export adobe pdf there is a check box called "Crop Image Data to Frames"

That should throw away any image data outside the frame for you.

But as Rik says resizing the image will helpl

[John Hawkinson]

Rik:

As has been mentioned above by a few people, having the images imported at final size (or close to) will help a lot with the InD file size which then translates into the PDF when you come to export. Its much easier to compress a 4mb image to 1mb than try and compress a 20mb to 1mb without changing the size (or losing a LOT of quality).

This doesn't make any sense to me. Unless we're talking about a bug here, it shouldn't make any difference whether ID is being asked to compress a

1200dpi image to 72dpi, or to compress a 150dpi image to 72dpi. You should get the same 72dpi image both ways. (Numbers arbitrary and for illustrative purposes, not necessarily appropraite for the original poster's question).

Compression is deterministic and mathematical. It's not hope-and-pray.

Crop Image Data to Frames will work for raster files (mostly), but won't work for vector graphics. If you have very large vector graphics, then adjusting them in external tools is relevant.

Really, the way to solve this is to go image by image and look at it Acrobat Pro and decide wheher ID is compressing it appropriately, and if not, why not.

I suppose there have also been issues with repeating images and bugs therein.

lizarddesign, what version of InDesign are you running? 7.0.4.553? 7.5.2.318? If it's anything else you should update.

[Peter Spier]

John Hawkinson wrote:

Rik:

As has been mentioned above by a few people, having the images imported at final size (or close to) will help a lot with the InD file size which then translates into the PDF when you come to export. Its much easier to compress a 4mb image to 1mb than try and compress a 20mb to 1mb without changing the size (or losing a LOT of quality).

This doesn't make any sense to me. Unless we're talking about a bug here, it shouldn't make any difference whether ID is being asked to compress a

1200dpi image to 72dpi, or to compress a 150dpi image to 72dpi. You should get the same 72dpi image both ways. (Numbers arbitrary and for illustrative purposes, not necessarily appropraite for the original poster's question).

I tend to agree, though I can see where if the image was significantly scaled down in ID  perhaps resampling in Photoshop first might eliminate enough data that there would be a difference in the compressed size due to loss of details (I don't really understand jpeg compression, but it seems to me to be quite variable in size for the same image dimensions depending on the actual content -- large areas of consistent color seem to compress smaller than lots of stripes or very complex photos, for example).

[John Hawkinson]

Peter:

though I can see where if the image was significantly scaled down in ID  perhaps resampling in Photoshop first might eliminate enough data that there would be a difference in the compressed size due to loss of details (I don't really understand jpeg compression, but it seems to me to be quite variable in size for the same image dimensions depending on the actual content -- large areas of consistent color seem to compress smaller than lots of stripes or very complex photos, for example).

Well, I think it's useful to look one level deeper into our oversimplification. When ID exports to PDF, there is a resampling step, and then there is a compression step. Assuming the image meets the threshold (i.e. "for images above XXX ppi"), InDesign takes the pixels of the image (which involves uncompressing JPEG or ZIP or whatever such that it has the raw array of uncopressed pixels) and resamples them down to the desired resolution. Only after that resampling is complete is the JPEG compression applied.

So, assuming they apply the same algorithms (Photoshop gives you slightly difference choices than ID does), they should both resample to the same information.

But you're right, JPEG compression is lossy compression, you don't get the same thing in as you get out, and there is necessarily some loss of detail. In general, though, this effect is dwarfed by the resampling. That is, JPEG compression of a 300dpi image will lose some detail in that image, but that same detail would have been lost when the 300dpi image was resampled to 72dpi. So if you resample the 300dpi image to 72dpi and JPEG compress it—or if you JPEG compress the 300dpi image, then uncompress it (losing information), resample that down to 72dpi, and JPEG compress it—both should get you nearly the same image.

It's possible to construct pathological cases where the JPEG compression might lose more detail than the resampling, and if your two resolutions were a lot closer than 300dpi and 72dpi, it might matter. For instance if you downsampled a 300dpi image to 280dpi, then the JPEG compression of the 300dpi image might affect the output.

Practically speaking, though, this should not be factor.

I do not see any clarity on the resolutions lizarddesign is working with in this thread, so I guess it is dangerous to assume too much...

Rik:

It's an interesting find because as you say image compression is all maths but seems to differ depending on the application. In Flash for example, if you bring in an image larger than the final size, scale down and then export a swf file, the swf file is larger than if you brought in an exact size image and exported the same way.

Well, there are differnet ways to solve the same math problem. Here it just sounds like Flash isn't resampling the image when you scale it. I don't know a whole lot about Flash, but I do know that it makes it easy to embed a particular asset inside the swf. So in the absence of reason to think it is resampling, I would expect it would embed the image exactly as you provide it. Kind of like ID with the "Do Not Downsample" set.

And of course another factor is whether the program crops out the image area that is unused. That may or may not be a signifcant factor depending on your application.

[Rik_Ramsay]

John Hawkinson wrote:

Rik:

As has been mentioned above by a few people, having the images imported at final size (or close to) will help a lot with the InD file size which then translates into the PDF when you come to export. Its much easier to compress a 4mb image to 1mb than try and compress a 20mb to 1mb without changing the size (or losing a LOT of quality).

This doesn't make any sense to me. Unless we're talking about a bug here, it shouldn't make any difference whether ID is being asked to compress a

1200dpi image to 72dpi, or to compress a 150dpi image to 72dpi. You should get the same 72dpi image both ways. (Numbers arbitrary and for illustrative purposes, not necessarily appropraite for the original poster's question).

John,

I stand corrected. I did a quick test using a 4" wide image and a 10" wide image, both at 300dpi and even though the original filesizes were much different, the resultant PDF was the same. So I guess to clarify, having the images at actual size helps InDesign, but doesn't make the resultant PDF any smaller.

It's an interesting find because as you say image compression is all maths but seems to differ depending on the application. In Flash for example, if you bring in an image larger than the final size, scale down and then export a swf file, the swf file is larger than if you brought in an exact size image and exported the same way.

[sheilaigne]

Did you also try and highlight and then remove any unused styles?

[lizzarddesign]

thanks, I haven't heard of that... How would I do that?  highlight what and what unused styles?

[sheilaigne]

For the different type of style Menus:

Example: Paragraph Styles menu--click on the upper RT corner icon option

and select "Select All Unused", you can then trash the lot at once.

Same for other Styles menus. It helps a bit.

[33_Steps]

FYI:

You may want to do a "Save As" to your InDesign file.

[Bo_LeBeau]

It might be helpful if we knew the actual resolution of the files as placed in InDesign.

Open either the INFO or the LINKS panel in InDesign, click on one of the images and it will show the Actual PPI and the Effective PPI. The Effective PPI is the important number.

In the image below you can see the actual PPI is only 72, however the image was scaled down in InDesign which raised the Effective PPI to 439.

Next, what are the settings you are using to export the PDF?

The final size of the PDF can vary according to the preset you select at the top of the dialog,

Click on Compression to show the settings. You can see that the PDF/X 1-a 2001 preset does less downsampling that the Smallest File Size preset.

Of course, the more you downsample the poorer the image, (more pixelation)

But its important to realize that the presets defaults allow for a much higher resolution before any downsampling occurs at all,

On the left you can see that a Color image will be downsampled to 300 ppi if and only if it is higher that 450 ppi

So the first image that was 439 PPI won't be downsampled at all using the default settings!

At default settings any color image below 449 ppi won't be downsampled.

Change the 2nd number to say, 310 ppi and any image above 310 ppi (rather than 450 ppi) will be downsampled to 300 ppi

You can also change the 1st number to downsample to for example; 260 ppi, 240 ppi, 225 ppi or whatever.

Click the images in the forum to see an enlarged view.