Scanning for Different Media
The scanner is a wonderful piece of equipment that allows us to copy documents, photos, images, and other items for use in our computer.
It works much like a copy machine, but instead of creating an image on a piece of paper, the scanner creates a digital image that can be displayed on a computer screen, manipulated, e-mailed, and/or printed.
Although the specifics of getting the best results from your scanner vary depending on what hardware you're using, there are a few general tips that can help you out. Most scanning software lets you select the mode. Adjust
the mode depending on what type of image you're scanning. The most typical modes are line art, halftone, grayscale, CMYK, RGB.
Line art is for things that contain solid areas of black and white. You use this mode if you are scanning a black-and-white logo off your letterhead or a pen-and-ink drawing. The key to this mode is that it doesn't read any shades of gray.
Halftones are pictures from books, newspapers, and magazines. When pictures are printed in newspapers, the continuous tones of the photographs need to be converted into tiny black dots of varying sizes. Pictures in books and
magazines are made up of dots too, only a lot smaller. In the case of color pictures, the dots are yellow, black, magenta, or cyan, all layered on top of each other to form the picture. Anyway, the halftone setting is for scanning these kinds of pictures.
To scan actual color or black-and-white photos, use the color and grayscale modes.
After choosing a mode, load your object to be scanned into the scanner face down on the glass, just like on a photocopy machine, and hit Prescan.
The scanner will take a quick pass of the image and display a rough version on your screen. This gives you an idea of what the final product will look like, but more important, it lets you specify which section of the image you
want to scan. Getting a high-quality scan can sometimes take forever, so don't waste your time scanning the whole thing if you just want a piece of it. Scanning the whole thing takes up a lot of computer memory; it's a waste if you're going to crop the photo later on, anyway. So use a selection tool to choose the area you want to scan.
Will my printed piece look exactly like it does on my computer monitor? There are differences. Scanners and digital cameras create images using
combinations of just three colors: Red, Green and Blue (called "RGB"). These are the colors that computers use to display images on your screen.
But printing presses print full color pictures using a different set of colors: Cyan (blue), Magenta (red), Yellow and Black (called "CMYK"). So at some stage your RGB file must be translated to CMYK in order to print it on a printing press. This is easily done using an image editing program like PhotoShop.
Caution: It's best if you do the RGB-to-CMYK Conversion of Your Images!
You will have more control over the appearance of your printed piece if you convert all of the images from RGB to CMYK before sending them to us. When we receive RGB images, we do a standard-value conversion to CMYK, which may not be perfectly to your liking. We want you to be happy, so please, take the time to prepare your file properly. We cannot be responsible for
sub-par results if you furnish low-res images or RGB images. Be aware that it is possible to make colors in RGB that you can't make with CMYK. They are said to be "out of the CMYK color gamut". What happens is that the translator just gets as close as possible to the appearance of the original and that's as good as it can be. It's something that everyone in the industry puts up
Scanning for output to the printer and scanning for the web require very different approaches. In both cases resolution is important. Think of
resolution as the third dimension of an image. Digital images have a width, a height, and the "third dimension"‹dots or pixels‹which make up the density of the value or color in the image.
You should scan your images using a resolution of 300dpi at the final dimensions you intend to use them so that your colors will look smooth, and
hard objects will look sharp. In other words don't scan at 300dpi and then enlarge the picture by 200% in your layout program! This is another reason why you should not use images that are lifted from websites; they are probably only 72dpi in resolution and will look very blurry if printed on a printing press.
If you are using pictures from your digital camera they will work just fine if they are jpgs; the quality of jpg images from digital cameras seems to be much better than jpgs that are used on the web. You must do the math to make
sure that it is high enough in pixel resolution though. For instance, if your camera puts out a typical image of 1280 x 960 pixels at 72dpi you get about 17" x 13" of photograph (at 72dpi); this is the same amount of detail as an image which is 4" x 3" at 300dpi so it's safe to reduce or enlarge that image up to about 4" x 3" in dimension.
If you are scanning the images yourself from photographs it is better to save them in either tif, or eps format. These image formats will preserve the color and sharpness of your pictures the best. File formats like gif or jpg compress the pictures color and pixel resolution and this can cause color shifts and blurriness. Since jpg and gif are the most predominant image formats on the web, it follows that it's not a good idea to simply lift an image from someone's website and use it in your layout.