| gray {grDevices} | R Documentation | 
Create a vector of colors from a vector of gray levels.
gray(level, alpha = NULL) grey(level, alpha = NULL)
level | 
 a vector of desired gray levels between   | 
alpha | 
 the opacity, if specified.  | 
The values returned by gray can be used with a col=
specification in graphics functions or in par.
grey is an alias for gray.
A vector of colors of the same length as level.
gray(0:8 / 8)