by Dean Cook, October 1, 2018
Category: Blog, Tags: best file format for print, best image format for print, bloated InDesign, bloated indesign files, bloated Quark XPress, decrease indesign file size, EPS, file formats Photoshop, how to reduce indesign file size, how to reduce large indesign files, huge InDesign files, indesign file size limit, JPEG, JPG, large InDesign files, massive indesign files, Photoshop formats, PSD, Quark XPress, reduce bloated indesign files, TIF, TIFF, which image format for print, why is indesign file large, why is my indesign file big, why is my indesign file huge,
With over 25-years in the industry naturally comes experience and, while the ‘if it ain’t broke, why fix it’ approach has always been a stable way of working, sometimes you need to periodically check if other image file formats offer a better way of working while meeting the compliant standards for commercial printing. Do you need to change formats because of evolving hardware, software and processes?
In the ’90s, when it came to photo imaging, there were only two main formats: EPS (Encapsulated Postscript) – not Adobe Illustrator’s vector format – and TIFF (Tagged Information File Format). While EPS and TIFF worked with Postscript printers, the software to operate them cost a small fortune compared to linear printers which were far more affordable. As such most designers opted to buy the cheaper linear printers and work with high-resolution TIFF images, however, the trade-off with productivity was huge. Using high-resolution TIFF files within Quark XPress using computers with limited processing power and a small amount of RAM often bought it to a crawl. Designers were either forced to break down larger Quark XPress documents as smaller files containing a few pages so working on pages became more manageable or they would need to employ a workaround solution such as placing separate low-resolution positional TIFF files then supply the high-resolution versions to the printers to be swapped out at prepress. This was a headache for many and somewhat time-consuming.
Investing in a Postscript printer offered accurate colour reproduction, but the main benefit was a greater level of productivity with larger multi-paginated files. The reason was, unlike TIFF, EPS had a built-in feature that offered a low-resolution 8-bit colour positional image that could be imported and positioned within Quark XPress documents. As only a low-resolution positional image was all that was required when preparing artwork, meant it kept the file sizes small therefore reducing the amount of processing power and RAM to handle the document. The clever part about this process is that the EPS’s high-resolution image data was only called upon when sending the artwork to a Postscript-enabled printer. It was an important factor, especially when working on multi-paginated documents. EPS proved to be a robust file format that allowed you to build pages from cover to cover, with speed and ease.
Towards the end of the ’90s, the PDF file format came into sight and, with a bit of experimentation distilling PS (PostScript) files, it quite simply revolutionised how artwork was dispatched for print. Embracing this new way of working, the PDF offered excellent compression rates for print while still being able to supply lossless images. With prepress RIPs (Raster Image Processors) increasingly processing PDF files, EPS-based images for all PDF generated artwork proved to be a solid way forward.
Embracing PDF, I moved away from reprographics and prepress to become more involved with design, production and construction of multi-paginated publications which can be optimised for a variety of output intents from a single InDesign file.
As widely known formats JPEG (Joint Photographic Experts Group) and PSDs (Photoshop Documents) do a job but from a production viewpoint they don’t do it well. As with TIFF they bloat the size of the Quark XPress/InDesign document, slows productivity, increases program crashes and can push through inherent issues to print. Okay, computer processing power and RAM is so much better today which lessens the speed aspect, but bloated QXP/INDD files increase the risk of crashes as the programs continue to handle far more embedded file information when, actually, there is no need to.
To find out what image formats would be best to use in InDesign, I decided to put together a little experiment. I created four identical 8pp InDesign files containing 20 CMYK images (as this is the output intent and gamut of full colour printing). The only difference being that each document contained images saved as each of the four file formats: JPEG, PSD, TIFF and EPS. Ensuring a level playing field InDesign files were then ‘Saved As’ to remove any inherent history information.
For this exercise, all JPEG images were saved with the quality set at ’12 Maximum’ to ensure a loss of image quality was minimised, TIFF files were saved with no compression, PSD files were natively saved, and EPS files saved using Binary Code. The typical file size of one of the larger CMYK images was as follows: JPEG = 16.5Mb, PSD = 42.1Mb, TIFF = 45.4Mb, EPS = 57.5Mb. Don’t dismiss these file sizes just yet.
Looking at the InDesign file, with High-Quality Display set, none were visually different from each other. The colour on screen was as expected. EPS offered up its built-in low-resolution 8-bit TIFF preview (top left) while in Typical Display (to help less-specified systems), JPEG, PSD and TIFF offered smooth yet large-pixel-looking preview images (bottom left). Open the image in a new window to take a closer look.
On my well-specified 27” 4.2Ghz Mac running external SATA drives via a USB3 hub, there was no lag between in High-Quality View or Typical View with exception to TIFF as InDesign had to redraw as pages came into view. I suspect increased screen lag will be more apparent on older or less-specified systems as no inherent preview facility is offered with JPEG, TIFF and PSD formats.
With all InDesign files looking identical, four variants of PDF files were exported each at 72ppi, 150ppi and, at 300ppi in both PDF/X1-a and PDF/X4.
Interestingly, the difference between each comparison was very little, and I would be happy for the files to continue their intended onward purpose.
72ppi PDF file: JPG=2.1Mb, PSD=2.1Mb, TIF=2.1Mb, EPS=2.4Mb
150ppi PDF file: JPG=7.9Mb, PSD=7.9Mb, TIF=7.9Mb, EPS=9.9Mb
300ppi PDF file (X1-a): JPG=25.6Mb, PSD=25.6Mb, TIF=25.6Mb, EPS=30.5Mb
300ppi PDF file (X4): JPG=26.3Mb, PSD=26.3Mb, TIF=26.3Mb, EPS=31.8Mb
JPEG, PSD and TIFF offered identical PDF file sizes. Noting the use of EPS source files are larger, the file size of the PDF did increase but export times were identical across the board.
So, if there is no real benefit which file format is used to construct artwork and export PDF files, what productive benefit can EPS offer over its file format counterparts? It’s not the image size of the source file nor the resulting PDF file size that is under the spotlight. It’s actually about working with lossless images while minimising the working InDesign file to maximise productivity. Let’s take a look at the InDesign file sizes using different image file formats.
Using JPEG images, the InDesign file size is 15.3Mb
Using PSD images, the InDesign file size is 17.7Mb
Using TIFF images, the InDesign file size is 15.5Mb
Using EPS images, the InDesign file size is 4.6Mb — yep, it is under 5Mb — well under a third compared to other InDesign file sizes.
The low-resolution positional images offered by the EPS file creates a leaner InDesign file allowing for faster productivity. For longer multi-paginated documents, such as magazines, you can work with robust lossless images that won’t bloat InDesign files and slow down productivity yet can deliver compressed flawless lossless files for commercial printing. Never again would you need to break down pages into several working documents to ensure your computer can still work.
InDesign, just a Quark XPress did, will only call upon the EPS file’s high-resolution image data when required, such as exporting a PDF or printing to a PostScript printer.
What would the InDesign file be like if I was producing a 132pp magazine, or, as I worked on recently, a 276pp product catalogue containing some 4500 images? With JPEG-, PSD- and TIFF-based InDesign file sizes there is a mean average increase of 350% compared to the EPS-based InDesign version. Potentially then the InDesign file of a 132pp magazine would increase in size from 83Mb to around the 300Mb mark, and my lean 332Mb 276pp InDesign file containing 4500 images could see it bloat to a whopping 1.2Gb. That’s a lot of data, and any part of it could induce a document crash.
While working with larger EPS files may sound ironic, it contributes to very lean InDesign files; this means working better, smarter, faster with no need to split documents across several smaller paginated InDesign files either.
Ultimately it does come down to personal preference. Referring to large multi-paginated documents, while all four image formats work, I would never use JPEG in artwork for print (“shock, horror”, I hear you say!). You see, it’s not about preserving data storage, it’s the JPEG’s damaging lossy compression that causes irreversible loss of quality in images, and it bloats the InDesign file by some way too (350%?). Replicating image quality and definition in print is key, not how much space it occupies on your hard drive.
Being lossless formats, TIFF and PSD are both very much on the same level. However, I am sure the majority will agree, PSD easily takes the lead out of the two as you can import native layered images directly into InDesign. It is convenient if you need to work in layers and, in these instances, PSD is also better than EPS but it will contribute to the bloating of your InDesign file. So, it’s always best to use PSD files only if and when you need to.
For the vast majority of flattened images, the lossless EPS is very much still the most solid format for print production. Yes, it requires more storage, but it’s how the low-resolution positional helps keep InDesign’s working file very lean, in turn, speeds up how it works with you. Being a sturdy format, EPS is quick to work with, quick to export and encountering technical issues is also extremely rare.
So, on that note, when working on time-sensitive publishing projects, we need to reduce risks, and one of them is to avoid bloating InDesign files which can slow up productivity. The CMYK binary coded EPS file continues to work beautifully today as it did at the start of my career. I still ardently remain that EPS is my preferred file format for flattened colour images for production and commercial printing.
Adobe’s Photoshop EPS – it’s more powerful format than you think.
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