HP L 5 manual Gamma Correction Command, ?*t#I

Gamma Correction

Color monitors, which are by nature non-linear, appear incorrect when given a linear ramp of some color. Gamma correction can significantly improve perceptual correctness by adjusting the brightness or darkness of the color data sent from the monitor to any other non-linear device.

Gamma Correction Command

?*t#I

#= Gamma number

Default	=	0 (gamma correction off)
Range	=	0.0 to 32767.0 (command is ignored for invalid values)*

* The practical range for gamma values is 0.0 to 4.0.

	Assuming 8 bits per primary (256 intensity levels per primary), the
	corrected intensity for each color primary is calculated as follows:
			1
			--
		Input	 y
	Intensity = 255 * 	--------------	
		255	
	Gamma correction is referred to in terms of device- dependent RGB.
	This command does not destroy the contents of device-dependent
	color lookup tables, but setting a gamma value supersedes any
	lookup table input in either Device CMY or Device RGB.
Note	The default value (0) gives the same result as a gamma value of 1.0,
	which results in a unity gamma curve.

EN Modifying Output Color (Color LaserJet, 5, 5M, DeskJet) D-17