I have removed the orange filter from the front panel display which has improved the visibilty of the display considerably while the box is in operating mode. However the clock is hardly visible when the box is in Standby. Does anyone known of a modification which will improve the brightness of the clock in Standby?
As Brian says, you could install the custom firmware and then the redring package.
One thing I will add though, the VFD (front display), will get fainter with age.
I have three HDRs. I have removed the orange filter on them all. The oldest unit has the faintest display of them. Not sure if redring can improve that. However, so mine all match, I have used redring to dim the other displays more so that they match!