Search Query
April
2003

Turning Screen Shots into Print

Fig. 1
One of the fundamental hurdles in producing a magazine about computers and software is how to get the screen shots of the computer display to look good on the printed page. All monitors display images at a resolution of 72dpi (dots per inch). Typically in print you want to use an image that is around 300dpi at the final printed size. This month I am discussing ways that you can get your screen captures to look good in PC Alamode (or any other magazine for that matter).

The first thing to do is set your monitor to the highest resolution you can (Figure 1), this will make all the icons and text smaller on screen and give you more pixels to work with. My screen, for instance is set to a resolution of 1600x1200 pixels. At the target dpi of 300, an image that is full screen on my 19” monitor will be 5.33” x 4”.

All commercial printers will tell you to use a 300 dpi image, it is an easy shorthand, but is not technically accurate. All you really need is double the line screen and I know people who have successfully experimented with a little less. The line screen, also know as the halftone screen, refers to the number of lines of dots per inch that will be used by the printer to simulate a continuous tone image. A laser printer is usually about 85lpi, a newspaper is typically between 85 and 120lpi and magazines use line screens between 133 and 150. The interior of PC Alamode is now being printed at 133lpi.

To make one halftone dot, or halftone cell, you need four pixels—hence the resolution needs to be double the line screen. I always target the double number (266 dpi at final size), because it is safe, it works, and it results in a smaller file size than 300 dpi. That smaller size was important when we used to transfer graphics files on 44MB SyQuest drives or 100MB Zip Disks before the era of writable CDs and broadband Internet connections.

One you have your screen capture, either with the built-in capture tools of your operating system (Alt-Print Screen in Windows or Command-Option-3 in Mac OS) or a third-party screen capture utility, you still need to format it for print. Bring the image into a graphics program like Adobe Photoshop or Photoshop Elements, JASC Paint Shop Pro or Corel PhotoPaint and then crop out any extraneous part of the screen (Figure 2).

Fig. 1

Using the techniques described in last month’s column (Resizing and Resampling, PC Alamode, March 2003), you can resize and/or resample the screen capture to get it to the target size and resolution. Images in PC Alamode are typically 3.5” wide for the smaller ones, up to about 5” wide for the larger pictures. At 266dpi, that’s at target size of between 931 and 1330 pixels; at 300 dpi that would be 1050 to 1500 pixels.

I like to reduce the size of the image without downsampling it. This only works well if you are capturing a fairly large section of the screen (600 or more pixels). You can resize it first and then resample it the rest of the way or you can do both at the same time (Figure 3). In Photoshop, make sure that the Image Size dialog is set to “BiCubic Interpolation” as it is the smoothest method.

Fig. 3

Many of the screen capture programs (I have Snapz Pro) will let you capture at a greater resolution or higher percentage. This is still interpolating the image, basically the same as Photoshop.

In Mac OS X, The native screen capture format is PDF. When I pull it into Photoshop (Figure 4), it allows me to specify a higher resolution, like 300 dpi. But even when I do that, Photoshop is still interpolating the image.

Fig. 4
Fig. 5

In any case, after you interpolate the image you can enhance it further by running the Unsharp Mask filter on it (select UnSharp Mask from the Sharpen submenu of the Filter menu). Although it has the weirdest name (it really should be called Sharpen Pro), Unsharp Mask works by accentuating the edges of the image and you can configure the settings to your needs (Figure 5). I usually use the following Unshap Mask settings for this kind of print image: Amount 300%, Radius .7 pixels and Threshhold of 1. The halftoning process will make the resulting image look better in print than it does on your screen.

PC Alamode is already a great, award-winning publication and it would be easy to stick with the present format. I have to thank Clarke Bird, our distinguished editor, for his continuing efforts to make our magazine the best it can possibly be.

Paul Vaughn is a freelance graphic artist, writer and web designer. Making screen captures for an article about screen captures is weird! If you would like to see the Graphics Guy address a specific topic email Paul Vaughn at paulv@mac.com.

 

|| Home || Graphics Guy || Mac Guy || Gallery || Payment || ||


This site and all images and text contained in it are ©2006 Paul Vaughn.
(Unless otherwise noted)
Questions? Problems?