# imggreyscale

Greyscale provides various methods for converting an image to greyscale. By default it takes a weighted sum of the red, green and blue colour channels with the formula: $0.298839 R + 0.586811 G + 0.114350 B$.

--average
Uses the average of the red, green and blue channels: $\frac{R + G + B}{3}$.
--lightness
Uses the average of the most and least prominent colours (ignoring the other): $\frac{max(R,G,B) + min(R,G,B)}{2}$.
--luminosity
Uses a slightly different weighting of the colour channels than default: $0.2126 R + 0.7152 G + 0.0722 B$.
--maximal
Uses the maximum of the red, green or blue channels. This produces a lighter image.
--minimal
Uses the minimum of the red, green or blue channels. This produces a darker image.
--red
Uses the values from the red colour channel.
--green
Uses the values from the green colour channel.
--blue
Uses the values from the blue colour channel.