I bought a Kodak filter viewing kit in a local photo shop (Georgeâ€™s Camera) for $24.95 (+Tax). It contains several color correction filters; cc10, cc20, cc40 of Red, Green, Blue, Cyan, Magenta, Yellow. These filters are low quality versions of the high quality Kodak CC gelatin filters, but perfect for experimenting.
The projectors differ in the amount of "light leakage" (blue and red), but you will most likely need a denser (higher CC number) Yellow (to reduce blue) then Cyan (to reduce red). Bear in mind that the use of filters cause light loss and color shifts that need to be compensated for. Not sure yet if filters are the way to go...
The bulb in the Hitachi is a UHB bulb (not UHP). I have tried to find a spectrum for it w/o success. This is something you may want to ask Hitachi about tomorrow. (Also please do not forget to ask them about policy of fixing/upgrading current projectors)
In any case I have done some measurements, and I easily saturate red on my projector, so I do not think that there is any excess red in this bulb.
For all tweaks, I think that it is absolutely necessary to measure the light output at Red, Green and Blue to determine the proper light vs. IRE response (the "gamma curve").
The cheapest way to do this is to use a Radio Shack photocell ($3) with the AVIA disk ($40) and supplied RGB filters. To do it yourself, needs some optical know-how, some of it which you can gain from reading Steveâ€™s web site:http://www.smartavtweaks.com/
Steve has also developed a nice spreadsheet to help you with the calculations, and you can also buy calibrated photocells, better filter sets etc.