Loading a linear LUT to the hardware while using PsychImaging

Hi all,

When loading a linear LUT to my hardware's graphics card, I still do not always get a true linear relationship between input and display values. This is sometimes causing problems with my Bits++ T-Lock code values being transformed slightly.

I have written a function that calculates and loads an adjusted LUT that will give me a linear relationship. However, when I try to use this in conjunction with the PsychImaging configuration functions ('PrepareConfiguration', 'FloatingPoint32Bit' and 'EnableBits++Bits++Output'), I get the error message:

Error in function LoadNormalizedGammaTable: Usage error
This window has already a new gamma table assigned for upload on next Flip!

Does PsychImaging load a linear LUT to the graphics card 'for me' and if so, is there any way I can overwrite this with my own, slightly adjusted LUT?

I am using Windows XP, Matlab 2011b, Psychtoolbox version 3.0.9 and an NVIDIA Quadro FX 3450/4000 SDI graphics card.

Thank you,

Craig Arnold