Get On, Clip In, Fall Off

What's in a test card?

There are plenty of sites out there with lots of pictures of television test cards. Most of them are "Hey, here are some pictures of testcards!"-type places with very little technical information on how they work and what makes a good test card. This is, of course, something in which most people quite rightly have no interest, but the geek in me finds such things fascinating.

This is why I was delighted (in a geeky kind of way) to find this page a while ago. While some people have long thought that George Hersee's classic Test Card F was about as perfect a test signal as it was possible to produce using a bunch of lines, some colours and a girl playing noughts and crosses, the digital revolution has changed this. The author worked with the BBC R&D department to update F for the digital age, and his detailed account of the pitfalls and problems encountered in creating both a standard 4:3 version (Test Card J) and, more complicatedly, a widescreen version (Test Card W) makes very interesting reading.

Probably not interesting for everyone, but certainly interesting reading for anyone who wants to know how it's possible to improve on perfection. While the subject matter is obviously pretty technical the broad outlines are easily grasped even if you don't know what a frequency grating's for and don't care whether you have a little chrom/lum delay. It's just a shame that as broadcasting is now a 24 hour business it'll be very, very rare to see these spanky new testcards in the wild.