DPI's, vs. Resolution vs. English
Sometimes you hear the Print guy saying: "It needs to be 300DPI!!" , or the Photograher mumbiling: "the images are high-res, raw JPEG, should be fine",
And all you bring out is: "WTF?"
DPI, pixels, JPEG, PMS, RBG colors, EPS files, screen resolution? Dazzled by mambo-jambo? We'll help you out and explain what it all means... in English!
Poor Brandmanager. They can't honestly expect you to know what all this means? Here's the secret, most people don't quite know what there talking about when it comes to screen resolution and file types. Here's the low-down:
600 DPI, 300 DPI or 72 DPI? Ok. DPI means Dots Per Inch. Maybe you remember printers having high DPI's, it simply means how many dots can they print on a square inch.
Why do you need a high DPI for print?
When dealing with print, you woud like the images to be crisp and sharp. A low DPI will make the dots visible, and the image will seem unsharp or low quality. So 'off-liners' will want something with a high DPI.
Ok, so what about screens?
Screens exist of pixels (basically the screen version of a 'dot'). Screens have a fixed amount of pixels. A typical screen can display could have 1600 lines of 1200 pixels. Depending on how large the screen is, the pixels will be closer together on a smaller screen = higher resolution. So, a SMALL screen with 1600 x 1200 resolution, will be able to show a sharper image.
Apple's new retina displays have a lot more dots per inch of screen, therefor are HIGHER resolution. "HD" format is 1920 x 1080 pixels. Guess what, if you look at HD on a really really large screen, it will still be blurry! And the HD televisions with the highest resolution are... the smallest!
What do I do when the printer asks for higher DPI?
That's really a trick question. What your printer is asking for is in fact more dots, not a higher DPI. He needs more image to work with. If you supply the printer with an image of 600 by 600 pixels, this would provide him with enough pixels or dots to print a 1 x 1 inch picture at 600 DPI. Tell him to print it smaller! Or be a smart ass and ask him to go with 300 DPI.