Quick ImageJ Tutorial: Scalebar calibration

Due to popular demand, I'll sporadically write up a series of posts on some ImageJ basics. For those not in the loop, ImageJ is a popular open source image processing program for microscopy; due to the availability of some rather sophisticated plugins, it can be a very powerful tool in the right hands. Also, the customiseable shortcuts are a blessing (and a curse for one's muscoloskeletal system, especially in the wrist region). I'm by no means anywhere near an expert with ImageJ (and don't do anything sophisticated, like macros or even much 3D/4D work), but there's a few basic things that I had to learn, and would like to share with anyone interested.

I put the rest of the post under the fold as most of you probably don't care...