zooming in on details

Thanks for all your input.  I went to the App store and purchased "Zoom it" for a small fee.  This software will do just what I want.  I can temporarily turn my mouse into a magnified circle and quickly return it to a normal mouse.  The software includes the option to control how much zoom one gets and many features to personalize the keyboard shortcuts.

I never found the system preferences to work for me.

Mary Lou

Which operating system?

For Macs, look at the Accessibility options such as the various Zoom features and Picture in Picture.

http://heresthethingblog.com/2014/02/24/mac-tip-zoom-entire-display/

For Windows, look up the Magnifier tool.

http://heresthethingblog.com/2014/03/06/windows-tip-screen-text-tiny-zoom/

Use keyboard shortcuts to switch between the tools to keep your presentation smooth.

Beside using Photoshop the tutorial creator uses their OS and some screen capturing software that can make video of the screen captured and the video files are also most likely edited to improve the tutorial.  The zooming may be done via an OS system feature,  As system add on,  An feature in the capturing application and in post production editing.  Your presentation need a real time solution for I'm sure you interact with you students.  If your students have computers access as you teach you most likely can find some software that would stream your display to their displays. Seeing your presentation would not be a problem.