QTR-Quadtone RIP

OK I know I'm answering my own posts!

> Toolcrib will auto-paste these values into Excel....  (looked like I was 
> getting somewhere) like this:
> 
> MGI RD-200 000255 

The useful part of this string are the values:
 
00095B          00077A              00301A

They are R-G-B as HEX values.

I can get all the measurements neatly and automatically into Excel, 
(each click on the densi pastes another reading into the sheet) then 
converted to decimal.  The lower the number the more reflective the 
surface.


How do I convert these  decimal RGB values into something that QTR 
will enjoy?

RGB to L ?  How to do that?

 I Have an IT8 target (Wolf Faust) which I might be able to use to check 
calibration...

Andy