Flash Duration, a technical note

Do you know:

• what the terms t.5 and t.1 mean
• the differences between variable voltage and IGBT flash units
• how colour temperature can vary with flash duration (and therefore power)

Here is a very good article about flash duration by Paul C Buff that is worth reading and answers the above questions.

Note: IGBT stands for Insulated Gate Bipolar Transistor.
Note: t.5 can be written t0.5 and the point may be a comma

Unfortunately the t.5 and t.1 times are not explicitly quoted for many flash units, I do not know what the values are for my monoblocs, though if just a duration is quoted then it tends to be the t.5 value at full power (as its shorter than the t.1 so sounds better).