Screen Resolution Explained

While I would love to see someone explain resolution using silly putty [nostalgia wave: Sunday comics and silly putty sessions!] this video explanation using a pin screen also makes me happy. It is clear and easy to understand and… fun.  🙂

This is all part of my quest to more fully understand resolution.  I thought I was doing ok, but recent experiences with recording a Replay screencast had me re-thinking my understanding.

I discovered that part of my challenge relates to the changing use of the term resolution. Many will use resolution to describe just the number of pixels high and wide a screen can display. However, it is more accurate to describe resolution in terms of number of pixels over a given area.  In other words, having a screen that can display 4500 x 3000 pixels is fine, but is it displaying that on a 24″ monitor or a 30″ monitor?  In my case, it is displaying that many pixels on a 28″ screen which gives me better than 4K resolution.

Pixels per inch (ppi) is perhaps a better way to think of it.  If you take a look at my image for this post, you’ll see a small 1″ square made up of 16 pixels – or 16ppi.  Then, there is a 2″ square that still uses 16 pixels. But, that equates to 4ppi.  This would be like stretching the silly putty to make the image bigger – it is bigger, but uses the same amount of info over larger area resulting in fuzzier image (lower resolution).   Basically, lower ppi = lower resolution = more jagged looking images.

So, what happens when you record a screencast at one resolution and display it at another?  For example, what happens when you record a screencast video on your cell phone (280+ ppi is not uncommon) and play it on a computer screen that can display 96ppi.  What about going the other way? What if you record at 96ppi and show that video on a screen that can display 300ppi?

These are the types of questions that keep me up til the wee hours geeking out on my computer. Stay tuned… I’ll be posting results of these experiments.  But, if you can shed any light on this subject – feel free to comment!  I know I could be way off base on any of the above ‘facts.’   🙂