Desktop Publishing

Scanning

We're not going to teach how to scan photos here, and chances are you've already done it. But we will discuss getting your scanned images ready for your printing service.

Photos and screens are all halftones. Remember those boxes we talked about earlier. If you fill a box with a 30% tint, then your print shop or typesetter will reproduce it with halftone dots. Why is this important? Well, there are coarse screens and fine screens, which are all measured by the number of dots per line.

For instance, coarse halftones may have less than 60 rows of dots per inch. The more rows of dots per inch, the finer the appearance. This is referred as the line screen and is measured as lines per inch (lpi). Finer line screens, around 133 lpi, have more cells per inch. The lower the lpi, the more visible the rows of dots, especially when printed at a low resolution, such as 300 dpi.

Images with a high lpi, look better when they're reproduced by output devices with a high dpi. So higher is better, right? Not necessarily, and this is where good communication with your printing service is important.

The line screen you choose should be based on a combination of factors: the quality of the inks, paper, and printing device being used. If you set the lpi too high, your printing service may have trouble reproducing the images on the paper stock you've chosen, so ask them for a recommendation.

Specify the line screen through your image editing software, or in PageMaker, open the Elements pull-down menu and select Image Control.

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Introduction