Preparing the Prototype - Paper Prototyping: The Fast and Easy Way to Define and Refine User Interfaces - page 119

Using Screen Shots
Assuming you want to use some screen shots in your paper prototype, here are some things you might
want to be aware of as you do your preparation:
Enlarge so that observers can see. This may not be necessary if you have a really good camera
setup or only a couple of observers, but if you have several people sitting around a table, most
won't be able to read an actual-size paper prototype. It can also be difficult for users to write in edit
fields that are sized for the screen, especially with a transparency marker. You might want to
enlarge the screens by about 30% to 50% by using a copier.
Remove defaults by whiting out radio buttons and checkboxes and then replacing them with
versions on removable tape as shown earlier in this chapter. Radio buttons may not be too much of
a problem because it's fairly clear that the removable tape supersedes the original default state of
the button. If the user unchecks a checkbox, however, it could introduce confusion later in the task
if your prototype still shows an X in the box.
Web-specific: Clear link history in the browser before making screen shots. If you don't, you're
practically blazing a trail to show users the correct path—the visited links usually appear in a
different color, even if you're printing in grayscale. One of my colleagues ruefully reported that her
users quickly caught on to the visited links as being the correct path, and it undermined most of the
value of the usability test.
Web-specific: Capture a whole page at once. Not all screen grab utilities can do this, although
this feature is increasingly common. SnagIt from TechSmith is an example of a utility that has an
auto-scroll feature, or you can simply print from the browser (as explained earlier, you don't need to
include the browser frame and controls if you create a browser background). Definitely avoid any
tool that requires you to paste partial screens together manually.
When you take these factors into account, you may find that it's just as fast to sketch some screens by
hand. Usually the best course of action is to do whatever is fastest to get your prototype together, then
modify it as needed as a result of usability testing.