Image Handling in Word 2007

This is a complex subject but I feel driven to try and explain it because of a mildly heated discussion I had on this subject with someone at my work recently. Someone who should have known better. Someone who creates complex Word documents containing images as part of their every day professional work—yet they seem to have a very limited understanding of how to work with raster images (which is what all ‘pictures’ are).

Basically, the bottom line here is that: The visual size of an image inserted into Word has almost nothing to do with the print resolution of the image or the actual ‘file’ size of the image.

Now, in as few words as I possibly can (really), I am going to try and show you the bare basics. Before I do I need to make three very important points:

1. For displaying images on a screen the optimum resolution is 72 dot per inch (dpi).
2. For printing images for normal corporate or home use the optimum resolution is something greater than 200 dpi and 300 dpi is a good number.
3. For printing images for commercial use (magazines, books, professional flyers, etc.,) the target resolution is 600 dpi or higher.

So the key numbers to take away from these three points in relation to resolutions for raster images are: 72, 300, and 600.

Okay. Now I am going to use an image featuring January Jones from the MAD MEN TV series for my following examples.

(1) From download into document

As can be seen from the Image Size data from Adobe Photoshop Elements at right, when the picture of January Jones was downloaded from the Web it was 1920 x 1200 pixels in size with a print size of 67.73 x 42.33 cms and a resolution of 72 dpi.

This is perfect for a screen wallpaper, which is the intended use of this image. It is 72 dpi, which is the ideal resolution for a Windows PC screen (but not for a Mac, BTW). The size is 1920 x 1200 so it has been designed by the person who made it to fit perfectly onto a 1920 x 1200 16:10 computer LCD screen. And if we were to print it from Photoshop it would print 67.73 cms wide and 42.33 cms high, which is slightly larger than a sheet of A2 paper (which is 59.4 cm by 42 cm).

The other thing you need to know about this picture—as it was downloaded from the Web—is that it is 986KB (1,010 bytes) in size.

Okay, now we know all this information about this picture that has been found on the Web and downloaded I am going to use Word to put it onto a standard A4 page (which would be, more or less, a Letter sized page for all my American readers). Following, shown in Word 2010, is this picture of January Jones on an A4 page.

So. A bit of Word auto-image-manipulation has happened here. Word has managed to put a picture that was parameterised to print on A2 sized paper within the margins set on an A4 sheet of paper. Word has, sort of (it is much more complicated than that) downsized the image by something like 50% so it fits perfectly within our page margins on a sheet of A4.

But it’s a trick. In reality the picture is the same size as it ever was. All Word has done is shrink the picture to fit on the page for viewing and printing. It has not reduced the size of the image file that is now contained within the Word document.

To prove this if I right click on the image in Word and select “Save as Picture”, as shown at right, then notice that the saved file is still 968KB in file size and 1920 x 1200 in picture size.

So even though Word has visually made the image smaller to fit the required margin space on the A4 page, the file size and picture resolution has not actually been changed.

Hence, if you were to include a picture from a 14 megapixel DSLR camera, which would typically be about 5MB (JPEG compressed for high quality), although the image is massively reduced by Word to fit the margin area on the page, the embedded file size will still be 8MB.

(2) Word and printing images

A question some people might be asking around about now is: As this was a 72 dpi picture when it was downloaded—as shown by the Photoshop data—what resolution will Word use to print it now that it has visually reduced the size?

This is an excellent question because although 72 dpi is exactly right for screen viewing we need about 300 dpi when we print in order to get a good quality sharp mid-contrast image.

If we really have to then we could maybe put up with about 220 or 250 dpi, but printing at 72 dpi would not be a good outcome.

It is technically impossible to actually show the difference between a picture printed at 72 dpi compared to a one printed at 300 dpi on a 72 dpi computer screen (duh). However I have tried to do an approximation in the two samples above with the image at left representing a crisp mid-contrast 300 dpi printed image and the picture at right depicting a 72 dpi hardcopy print.

To the untrained eye the sharpness difference in these two pictures might not be obvious but when it comes to printing professional documents and magazines it is vital that images be printed at 300 dpi at least, and 600 dpi is often used.

By default Word will try and print embedded images at 220 dpi however Word will not up-sample an image. This means that if the embedded image is greater than 220 dpi, say 300 dpi, then Word will (by default) print it at 220 dpi. If the embedded image is under 220 dpi then Word will print it at the embedded size—so a 72 dpi embedded image will print at 72 dpi.

So the answer to the question at the start of this section is that Word will print the picture of January Jones at 72 dpi because this is the size specified in the JPG file and, by default, Word will not up-sample images lower then 220 dpi.

For most people taking a casual glance this will be okay. For a school assignment it is probably okay. But for corporate use in training material, or reports to shareholders, or monthly or quarterly reporting, etc., documents printed containing 72 dpi images are at best worth a B, and maybe even a B-.

The best idea when putting images into a Word document, or any other document for that matter, is to take full control and edit and prepare the images prior to them being inserted into the document. Using your favourite raster image editor crop, adjust, and resample your images to the required exact print size and resolution, and then insert them into the document. This way Word does not do any internal re-sizing or re-sampling and the image will print at the resolution you set in the image file.

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I am not good at summarising stuff. This has become a long post. In a future post, assuming I don’t forget, I will put together a post on the basics for preparing images for inserting into a document in order to get the best result when the document is printed.

The key things to take away from this post:

• 72 dpi is perfect for on-screen viewing but almost totally useless when it comes to printing images.
• For printing images you need to aim for 300 dpi, but 220 dpi is just good enough if you can’t make it to 300 dpi (because up-sampling raster images is generally a bad idea).
• Word will not up-sample images. So any images inserted into Word that are under 220 dpi will be printed by Word at the resolution specified in the JPG data.

Hope that all makes sense. There is a lot to it, but if you put images into Word documents as part of your work it is worthwhile understanding how to get the best results so you don’t produce B grade results.

Obviously none of the above applies to vector images as image resolution is not a concern with vector images.

I should also say before I close that Word is not designed to be a page layout publishing tool incorporating sophisticated raster image handling capabilities. While it handles many layout options reasonably well it is first and foremost a word processor; albeit that it has significant features and enhancements beyond being only a word processor. If you are are working on something that is more of a page layout job, like a book with pictures in it, or complete manuals including pictures, or a magazine, then you should consider using a page layout product such as Corel Draw (which incorporates Xerox Ventura Publisher), Adobe’s InDesign (PageMaker), or the granddaddy of them all (if you are really serious about this), Quark.