More often than not, it seems the hands do not match the lume color for UG, I figured they just age differently for whatever reasons.

Reading Sala book today, I noticed for the first time that most (maybe all? haven't checked) of the lume on the dials is described as tritium, and most (perhaps all?) of the lume on the hands is described as radium.

First off, is this really true, that different materials are used for lume with UG, in the dial vs hands? (and if true, is this also the case with other brands?)

And second, is this why they often do not match color?

In general, it seems like the hands are often much lighter color than the dial.

Random example photo pulled from internet...........