Scanning Tips

Make a Resolution to Scan Smartly

How to Choose the Correct Scanning Resolution for Your Project

When you attach an image to an e-mail, you want a good quality image that will open quickly and will be accepted by your e-mail program as well as that of the recipient. 72 psi is the standard resolution used for attaching images.

If you frequently scan images for your digital designs, it helps to understand how the resolution affects the quality of your images.

Higher is not always better.

A scanned image is a resolution-dependent raster image which means it can not be resized easily without a loss of quality. Therefore it is important to use the "right" resolution when you scan - not too high - not too low.

When you want a large printout of a photo or layout, you need at least 300 psi.

When you scan images, if you are planning a 300 psi document, you should usually scan elements in at 300 psi. Never use a lower rez than the project you are working on.

The only instance I can think where you might want to scan at a higher rez is if you want to scan something very small and add it to a large 300 psi image. If you scan the tiny thing at 300 and need to stretch it substantially for your layout, it will appear pixelated.

Understanding how raster images work definitely helps you to scan smartly.

So plan ahead. If your project will be used in several ways, for example as a 12 x 12 scrapbook page to be printed out and also loaded up to an online gallery, start with the highest rez and largest size your project requires. Save that to one name. Then make your smaller versions, if any, and save them to different names.

If you are forced to use a low rez raster image in a larger file using Photoshop, select Image>Image Size. Type in the higher resolution, make sure the Resample Image box is checked and choose Bicubic Smoother from the drop down menu.

That tells Photoshop to interpolate new pixels between the existing ones moving from each pixel's color to the next in as smooth a fashion as possible.

P.S. When you use the Image Size box to reduce resolution, you can sometimes get better results by selecting Bicubic Sharper from the Resample Image menu. Try both ways and see which you like.

Remember you can undo work in Photoshop simply by going to the History palette and backing up a few steps. If you don't see the History palette, select Window and put a checkmark next to History.