Ever since I became a graphic designer back in the early 90s when designers started using computers, I’ve had to “educate” my clients on the use of digital photos in print materials. Specifically, how pixels per inch—or resolution of a digital photo— affects the quality of the photo when it’s actually printed.
Have you ever seen a low-budget advertisement or printed piece where the photos were blurry or even pixilated, like the image shown in this article (in a square grid of pixels)? This happened because the designer used a “low resolution” digital photo – most likely something that was below 150 pixels per inch, or even as low as 72 pixels per inch, which is the DEFAULT resolution setting on any digital camera.
In order to create a high resolution image from a photo taken with a digital camera, a designer imports it into a photo manipulation program like Adobe Photoshop and goes into the “Image Size” dialog box and “constrains” the resolution, so that while the resolution goes from 72 pixels per inch to the ideal 300 pixels per inch, the size (in inches) of the image actually shrinks. If a designer were to use a typical photo taken by a cell phone camera exactly AS-IS, which on the computer screen looks to be about 4×3 inches, the resulting photo would be pretty blurry in print. On the computer it still looks okay. That’s because a computer monitor is 72 pixels per inch. But the dots, or pixels, of offset or digital printing, are much, much smaller and require a tighter resolution than 72. (Incidentally, the image shown with this article contains a photo that’s about 25 pixels per inch next to one that’s 72 pixels per inch. Since you’re looking at this on a computer screen, only a resolution of 72 is needed for quality and clarity.)
Without having Photoshop, how would you, the client, know how large your photos will be able to print and still retain good quality? Take a look at your camera settings and compare them to the chart below:
If your camera’s photo resolution setting is…
3888×2592 = Your photo will print out 12.96 x 8.64 inches at 300 pixels per inch.
2816×1880 = 9.387 x 6.287 inches at 300 pixels per inch.
1936×1288 = 6.453 x 4.293 inches at 300 pixels per inch.
1200 x 1600 = 4 x 5.3 inches at 300 pixels per inch.
640×480 (most cell phone cameras) = 2.133 x 1.6 inches at 300 pixels per inch.
Here are some Do’s and Don’ts regarding digital photos and resolution:
DO set your camera at the highest resolution setting available. You can size the photos down later or have your designer size them down in Photoshop.
DO NOT use a cell phone to take photos that will appear in print, unless you don’t mind photos the size of postage stamps.
DO use a flash for low-light settings.
DO NOT expect that your photos will be able to be blown up to a much larger size than the chart above indicates without expecting a loss of picture quality in print.
DO use a low or medium resolution setting if you will ONLY be using the photos for a website and never in print. The size of the photo as it appears on your computer screen is the size it will appear on any website or e-mail.
DO NOT ask your designer if they can “make the photo bigger and increase the resolution, too.” It doesn’t work that way. There’s no software or technical advance that can add digital information to a photo to make it sharper, crisper, less blurry or have a higher pixel-per-inch count.
DO NOT use photos directly from your digital camera or cell phone in a printed piece that you’ll be submitting to a printer. These photos are not the correct color scheme (they’re RGB, not grayscale or CMYK for full-color printing) and they’re likely still low-resolution (72 pixels per inch). Your photos will need to be converted to either black and white or CMYK, and then constrained to a resolution of 300 pixels per inch.
DO use stock photos from websites such as Dreamstime or iStock. They are already high enough resolution if ordered for “print use” and sometimes even in CMYK mode.
If you have questions about the use of digital photos, stock photos or file conversion, please contact me.
