High-quality prints from slides

December 29th, 2010 by bluewave

We are occasionally asked to turn presentation graphics into printed posters, white papers, newsletters, and so on. If you think you’ll need high-quality print output from slides, it’s best to let us know in advance. Here’s why:

Presentation graphics do not need to have anywhere near the same resolution as high-end print graphics—they only need to match the resolution of the display device (monitors, laptops, video projectors). Display device resolutions are measured in pixels per inch (ppi). How an image looks on screen is determined by the display device resolution—the number of pixels it can display in a given area.

For an image to fill the entire slide, the size of the image in pixels should be at least equal to the display device resolution. For example, if display device resolution is 1024×768 (a common setting for monitors, laptops and video projectors), then full-frame slide graphics should be 1024 pixels wide by 768 pixels high. In practice, Bluewave generally creates presentation graphics at somewhat higher resolutions that this—densely detailed images may project better if they’re created at slightly higher pixel dimensions (1280×960 ppi, for example) and then scaled down slightly to fit the slide frame. A bit of experimenting will determine the best resolution.

However, super high resolution images (way higher than needed by the display device) won’t look any better when projected. And the file size can be huge, resulting in slow-to-load images and sputtering slide shows. The key is to produce presentation graphics at just the right resolution—not too high, not too low—that project beautifully and run flawlessly.

High-quality print graphics are usually created at 300 dots per inch (dpi)—the industry standard and a far higher resolution than needed for presentation graphics. Dpi refers to the density of ink dots printed on paper—not the same animal as ppi, although the two are somewhat similar and often confused.

Slide graphics will look just fine printed on most desktop printers. But for high-end printing, lower resolution graphics that look great on the screen will likely appear fuzzy or jagged when printed because there is not enough pixel information in the image.

Unfortunately, simply adding more pixels to lower resolution graphics via a photo-editing program doesn’t do much; the image won’t look more refined or detailed and in fact may look worse in some circumstances. And it certainly won’t result in high-end prints. Basically, the graphic needs to be recreated from scratch, at a higher resolution. Obviously, this takes time and can seriously bloat the budget.

Thus, if you anticipate needing high-quality prints of any slide graphics, let us know ahead of time. We’ll create specific graphics at 300 dpi for printing and save lower resolution images for placing on slides.

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  • 1 Jerry Jan 25, 2011 at 3:07 pm

    Great information, Thank you