Why Is My File Size So Huge?
Ben wrote:
I have a 60+ page CS3 file that saves at around 450MB and growing. Doing a quick preflight check shows that there are no embedded images nor saved image previews. The linked photos themselves are high resolution, around 2-3MB a piece. If it’s not saving any image data and merely linking 500 .jpg images, why would this file be so large?
Ironically, I know the answer to this one because of my long history with QuarkXPress, which also exhibits this curious phenomenon. There are a number of things that can make your InDesign files huge. The first thing to always try when trying to reduce file size is to choose File > Save As. That clears out any gunk that has accumulated while you’ve been working on the file.
However, in this case, the problem is, in fact, your images. These images were probably saved from a digital camera to disk, and then imported directly into InDesign. Unfortunately, many cameras save their files at 72 ppi (pixels per inch, sometimes called dpi). It may be a 17 MB, 3000 x 2000 digital capture, but if it’s saved at 72 ppi, then it’s about 41 by 27 inches large. So you import it into InDesign and scale it down to the proper size, which increases its effective resolution (watch the Info palette to see original vs. effective ppi).
Now here’s the rub: When you import an image, InDesign saves a low-res “thumbnail” preview of it, right? That’s what’s stored in the InDesign file itself (so you can still see the image if the original on-disc image is missing). But when you import a 72 ppi image, InDesign saves the entire image as the preview! It essentially embeds the whole thing because it’s trying to save a low res (72 ppi) version of your 72 ppi image.
The solution: 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.
Sure, there are other reasons that InDesign files can get huge, but images are the main problem I’ve encountered.
(By the way, I discovered why InDesign files jumped in size between CS and CS2: Color management was turned on by default in CS2 and InDesign started embedding CMYK profiles in its files. A CMYK profile may be 1-2Mb in size, so the minimum InDesign file size–what you’d get if you just had an empty INDD file–suddenly got much bigger.)
By the way, Ben later replied:
A quick batch in Photoshop helped me to fix these up to about 180dpi at no larger than 8 inches in either horizontal or vertical. The file size wasn’t decreasing until as you suggested doing a simple Save as. Sometimes it’s the slightest things that can trip you up.
That’s great to know. It seems pretty obvious, but I wasn’t even thinking about it.
This is a great tip!
Just a quick addition:
For commercial printing the effective resolution of images are best at 300 ppi
Technically speaking ppi for print should be at twice the lpi that you are going to print at. The two most typical lpi’s that we use for products at work are 133lpi and 150lpi, so the image should be at 266ppi or 300 ppi. As Stuart said 300ppi is a good base for most print because the RIP can throw out the extra data of the larger image that it doesn’t need when processing the image for a lower lpi and the files are not that much larger than the 266ppi files are. When doing covers we typically do them at 350ppi for 175 lpi or 400 for 200lpi. If we don’t know what the lpi is going to be when we start building the files then it’s best to make them at a larger resolution.
For video display I typically build in multiples of 72ppi since most video applications are build off of this standard. So I would make them at 72ppi, 144ppi, 288ppi.
I usually like to build files at a larger resolution so that I don’t have to rebuild them when the client decides that they want to repurpose the image for another application. This is especially important when building images for web that you think they might also want to incorporate into a print product.
Stuart and Jerome, you guys are just baiting me because you know this is a pet peeve of mine, aren’t you?
Doesn’t anyone read Real World Scanning & Halftones, or Real World Photoshop anymore? Sigh.
There is very little reason to ever use more than 1.5 x your halftone screen frequency. Yes, I know everyone says “2x lpi” but when pressed they insist that they do this only because they were taught it by someone else. For traditional spot halftone printing, 1.5 x lpi is good.
Therefore, if you’re printing with a 150 lpi halftone screen, you almost definitely don’t need more than 225 ppi images. There is a huge difference between file sizes at 225 and 300. (Doesn’t sound like much, but try it!) So the only time you need 300 dpi is if you’re printing at 200 lpi (still not that common).
I would never use any image resolution above 300 ppi for halftone printing because the resolution is too small for the human eye to resolve.
I might increase to 350 or 400 when printing with stochastic screening, but even then I think its highly unlikely that any normal person would be able to see the difference between a 300 ppi and 400 ppi image.
Keep your files at a reasonable size! Don’t use such high resolutions.
I recently generated a 3d image of a book from a flat scan of it’s cover. I had everything superbly done (if I must say so myself) through illustrator, photoshop and Indesign. Illustrator to create the 3d, photoshop to do the necessary shading and generating the area to look like pages at the edges, then indesign to make the shadow. I thought I was clever in putting one image in indesign and duplicate it. But it seemed to take forever for indesign to respond to the simplest page or just skim past the page. So I ended up duplicating the image in photoshop and applying all my shadows and effects there, made a psd so I didn’t get a white a background and hey presto the system responded much quicker.
I guess it’s just easier to do some effects with photoshop and flatten before they get to indesign. (Don’t worry, I kept and unflattened unused version of it incase I needed to make changes).
[quote]Doesn’t anyone read… Real World Photoshop anymore? Sigh.[/quote]
I do, David! Course, it’s the Version 5 edition, but it is still full of valuable info. I know this is off topic, but I’ve learned more from that one book than anywhere else. I particularly love the trick about getting good line art scans.
I was just referring to the book yesterday, as a matter of fact!
I wonder why anyone is printing CMYK sheet-fed offset work with a printer who runs less than 250 lpi?
This problem is known since the 1st vertion of InDesign. It has been happening because the InDesign format is based on PDF format. The growing is PDF native problem. The problem also meets in Illustrator, but in AI each save really is save as.
Alexey, InDesign and Illustrator are definitely not based on the PDF format. The “Save As” fix (making files smaller) works in many programs, including QuarkXPress and PageMaker.
Save As works to making files smaller in all programms, bacause rebuilds the files. Turning to PDF in Illustrator (from PostSctipt) in 9 version has allowed to support effects and transparency. In InDesign has used same graphics language based on PDF. Now Adobe moves to PDF as main graphics language from PostScript.
The ‘Save As’ trick also works in MS Word; it’s a fairly safe bet *that* isn’t based on PDF…
I’m glad I found this tip, anyway: I was a bit disappointed when un-embedding the images in my 110 Mb .indd file turned it into a 135 Mb file! Now I have a nice 49 Mb file instead…
Re: 8. Christopher Gomez said: “I wonder why anyone is printing CMYK sheet-fed offset work with a printer who runs less than 250 lpi?”
I assume you meant ppi. There are decreasing benefits to increasing the line frequency beyond 175 as you start to run into problems related to the physics of ink chemistry. In visual terms, the dynamic range tends to decrease resulting in greater detail at the expense of lower contrast (and frustrated, angry pressmen/women).
I’m working with InDesign CS3 about a month now. Last week I’ve completed a magazine lay-out of 36 pages. All full colour with many images in it, a few of them the whole page covering. I noticed at the end the filesize did grow to 250 MB, normally in CS2 this sort of magazine would be 20 till 30 MB. So, searching the web for a explanation I found the tip to use Save as… at the end. That decreased the filesize to 160 MB. More than 90 MB less, but still much more than the usual CS2 filesizes.
The images I use are all converted in Photoshop to CMYK, 300 dpi. CMYK profile included. There are no 72 dpi images used.
A suggestion of David Blattner made me to export to INX. The INX-file seems very small, about 2 MB. Opening the INX in CS3 and saving it will bring the filesize back to 170 MB.
Secondly I imported the INX in InDesign CS2. By saving it the filesize reduces to 17,4 MB!!! After that I opened the CS2-file in CS3 en saved it. The filesize is now 17,5 MB. That’s more like the filesize was, but not a nice workaround…
Does anyone has the same problem? And maybe a solution?
Not the info I was looking for but a fabulous tip and insight into how InDesign works!
Re: C. Gomez–I have only worked with one commercial printer that exceeded the standard 150-175 lpi past 200, and they were only doing it for publicity. I have also been told by printers, as B. Glasglow says, that 175 really is optimum for today’s workflows.
To David: the reason so many designers routinely save images higher than 300 (or even at 300 when they don’t need to) is because something always happens and one needs to resize larger in InDesign; there might not be time to go in and carefully fix/resize images like we used to.
It looks like you guys already figured it out but we were just working with an indesign cs3 file that was around 65MB and we simply exported it out as an interchange file (INX) and it reduced the document to 15MB. It’s still pretty rediculous considering there are no linked files but it’s a good quick fix if all you need is a band aid.
Good comments.
Is there a way to find out what dpi all the images in a document are?
Thanks