Am looking for any info about the greyscale that the clickpad/touchpad nspires are using with their b/w lcd. Not much what I find. A greyscale prog I could find, but it works only with Ndless. So how can someone use the greyscale in progs without info about the relation of r/g/b values to grescale 0-15? Ok, not really useful to search longer, I am writing such a program in Lua that shows this values and the related grey by a simple grafik. Am sure that a used coder would do it in shortest time, however, it's a good start for first steps in Lua. But: is there anywhere the info about the r/g/b values of the greyscale?

Hi,
thanks for this info, but that is already clear for me (as radio/tv technician it should :-) ). My question is: to which of the 16 gray stages are which r/g/b values related? Up to now I see that this 16 greys are not spreaded over the 8 bit (would mean all 16 bit are a quant to next grey stage) but at about 176 I see the grafik starting to get a little lighter. And this seems to be spreaded over red and green, but blue seems not affected (am just trying this,may be it's not correct). So I am still looking which grey needs which r/g/(b) value. Should be a simple question but also at this lua pages (and TI pages) I didn't find any info about this.

Hi,
even though it seems like your problem was solved, I think I can still give some more useful information about this topic:
I messed around with the grayscaling of the emulator and found out that the Nspire (at least the emulator) apparently uses the commonly used RGB-channel weighting of 0.299*R + 0.587*G + 0.114*B. You can see that on the attached screenshot (even though the emulator seems to mess up certain RGB-values like 0,129,0). Based on this and the fact that the Nspire can display 16 different shades of gray, I assume that the Nspire calculates the displayed shade like this:
shade = floor((0.299 * R + 0.587 * G + 0.114 * B) / 16)I can't test if that's the case myself because I don't own a grayscale Nspire, but this would explain your confusion with single colors of r/g/b. 

Well I think you got me wrong here; the best way to get certain shades of gray is to set R,G and B to the same value. The formula would just explain how the Nspire transforms colors to gray shades. E.g. if you'd gc:setColorRGB(150,100,255), then, according to the formula, floor((0.299*150+0.587*100+0.114*255)/16)=8the Nspire would display the 8th shade.