How to safely increase DPI for printing

IMGP0057

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I found an answer to this DPI thing.

Oh, that's right - only one of you knows anything about that! In a nutshell, my Pentax (which rocks) saves images at 72 dpi. Great for the web, sucks for printing. Most stock sites want an ideal size of 300 dpi. Adding pixels, which you can do in image editing softwares like Photoshop, does NOT improve the image quality and stock sites tell you they'll reject images that have been artificially upsized. I couldn't figure out why, or how to get around this, until I came across this little bit on a message board that I have to now pass on to you so that if ever in the future you need to know this, it won't take you four plus hours to find out!!

"How to calculate the size you must reduce (shrink) an Internet image to get it to print well:

Reduce the size to 24% of its original size. (Because 72dpi is 24% of the 300dpi resolution you want)

Example:

Internet Image that is 3 inches x 3 inches, at 72dpi
You want to shrink it enough to get it to 300dpi for crisp printing
72/300 = 0.24
3 inches x 0.24 = 0.72 inches

Zoom into your images to see the quality. Be aware of your design, purpose of your printing, and the needs of your customers before using images from the Internet. "