Screenshots of this are tricky unless you literally mean "photographs of the monitor", as I suspect the way this is done is by modifying the gamma tables in the

Screenshots of this are tricky unless you literally mean "photographs of the monitor", as I suspect the way this is done is by modifying the gamma tables in the graphics card. This gets applied post-framebuffer in the RAMDAC (for VGA) or in the TMDS frame assembly stage (for DVI/HDMI/laptop panels). In other words, the framebuffer, which is what you're normally reading for a screenshot, always contains the same data, it just gets tinted as it is sent to the screen. Graphics card drivers often come with UI to modify this rendering stage, and the windowing systems all come with APIs for manipulating it from user space. Of course, you could always take the framebuffer and aproximate the transformation in software and dump the result to file.