Using the Correct Color Mode and Resolution for Print
I recently explained the need for correct image resolution and color mode in response to a friend’s Facebook post. My friend works for a major metropolitan newspaper, and was frustrated by the continual submission of low resolution images that were not usable for print. Are you making the same mistakes? Do you know how to set up an image properly for print? For images, two of the main requirements are using the correct color mode and resolution.
Here is a brief explanation. Print uses pigment inks and the web uses light colors. Think back to your high school science class, and it may be easier to understand. For print, the correct color mode is CMYK, which is comprised of separate channels for each of the process color inks used, Cyan, Magenta, Yellow and Black. Images to be used online has a color mode of RGB, with channels for Red, Green and Blue. If an image is the wrong color mode, it may not reproduce correctly since it can not be separated into the correct channels.
A web image is typically 72 ppi; this is referred to as resolution. That’s all that’s needed for a monitor, though this rule of thumb may be increasing to double that size with retina monitors. Print resolution needs to be much higher, at 300 pixels per inch. Images printed at a lower resolution will appear jaggy or fuzzy. Pixels per inch are sometimes referred to as dots per inch. You may see your resolution by looking at the Image Size in Adobe Photoshop. If you don’t have access to Photoshop, this link has a way to check an image resolution in Windows Explorer: http://www.ehow.com/how_6906723_determine-image-resolution.html
Pixels per inch are resized proportionally. If you have an image that’s 2″ x 2″ at 300 pixels per inch, and enlarge this image to 4″ x 4”, the resolution will drop to 150 pixels per inch. You can not enlarge an image beyond it’s original size, because the resolution will decrease proportionally. If you have a high resolution image, you can decrease the size, but not increase it. The only time you should use an image at a size larger than the original is if the resolution is greater than 300 ppi. If the 2″ x 2″ image has a resolution of 600 pixels, you can increase the size to 4″ x 4″ and it will be at 300 ppi.
Are you confused? Until you have worked with resolutions and color modes, and viewed the differences on press, it can be difficult to understand. Just keep in mind that for print, the color mode should be CMYK and the resolution should be 300 ppi at this size you intend to use the image. If you’re rather leave the design and pre-press work in the hands of a professional, contact ImageSmith Creative.