How can I set timestamp format in script ?

I want to change the $timestamp format and add colors, but if I use the color in mirc settings to edit the timestamp, it just changes back to default.

Where would I set the timestamp format and with what syntax so that it is set each time mIRC loads up ?

Thanks

Put the /timestamp -f command into an on START event, so that the timestamp is set each time mIRC is opened

Code:

on *:START: {
  .timestamp -f 4[HH:nn4]
}

this will make the timestamp look like [HH:nn]

Thank you very much