Image files for print are different from the ones that you see on your screen. The resolution for screen images is most often 72 dots per inch (dpi). The resolution needed for printing in a magazine like the Journal is 300 dpi. An image that fills your screen and then some, perhaps 10 “ square, would print out at a little over 2” square in the magazine. Printing it larger, without a larger file, just means you print the dots bigger (pixilation). You won’t be happy with the way that looks and either will we. Since it isn’t until late in the layout process when we decide which images are where and at what size in the magazine, we need files that will cover a whole page, just in case your picture is the best for, let’s say, the cover of the magazine at 8” x 10”.
Color in printing is also different from color on a screen. The printer uses inks in 4 colors, Cyan, Magenta, Yellow and Black (CMYK ) to approximate all the colors in the visual spectrum. The screen on your computer uses three colors of light–Red, Green and Blue–to accomplish the same task. Since the image file we send to the printer contains color information and instructions for displaying or printing each dot, we have to make sure we send the printer the file for printing, not the one for displaying on a screen. RGB files are for display, CMYK files are for printing.
And now a little about file formats: The storage of information used to be very expensive, and file sizes for images, music and video are quite large. To minimize storage space, methods of compressing that information were developed pretty early on in the digital game and compressed files are perfectly useable for most intents and purposes. One of the most popular compressed image-file formats is JPEG (.jpg). The problem with compressed image formats is that the computer recompresses the file each time it is re-saved. This is like photocopying a photocopy. Each time it is changed and saved, you lose a little of the information in the file and pretty soon the image starts to degrade. You won’t notice it at first on your screen, but it can really make a difference in a printed image. File formats that are “lossless” do not compress the information at all. They are not the most economical in terms of memory space, but that is far less of a problem these days, since computer memory has become quite cheap and plentiful. TIFF (.tif) files are the standard for images, and this is what our printer requires. We can open the file, clean it up, change it, adjust it, change its filename, etc. a dozen times and the whole file is still there with no loss in quality.
Bottom line? We need image files that are big. 300 dpi files saved in .tif format in CMYK color space, even for black and white, since the printing is done with color inks. Transfer of these files is not easy by email. Go to Wetransfer.com and send them to me at firstname.lastname@example.org. They send me a notice, I download your files. Simple.