Professor Ripley thanks for this.
>> >> plot(1:50,pch=16,col=hcl(h=240, c=50, l=1:50)) >> >> I get mostly blue, but also some red, dots. Note that h=240 >> throughout. If 240 is blue, >> how come there's a red dot there? Or is it just my monitor? > >> hcl(h=240, c=50, l=1:50, fixup=F) > [1] NA NA NA NA NA NA NA > [8] NA NA NA NA NA NA NA > [15] NA NA NA NA NA NA NA > [22] NA NA NA NA NA NA NA > [29] NA NA NA NA NA NA NA > [36] NA NA NA "#08628E" "#126490" "#196693" > "#1F6995" > [43] "#246B97" "#286E9A" "#2D709C" "#31729F" "#3575A1" "#3877A4" > "#3C7AA6" > [50] "#3F7CA9" > > You have mainly used invalid values: you cannot have high chroma and > low luminance (and there are warnings to that effect on the help > page). > > Not sure the chosen mapping of out-of-gamut specs onto the sRGB gamut > is particularly helpful, though. > Yes, this is what I was missing: with fixup taking its default value of TRUE, out-of-range combinations are silently mapped to real RGB values, [although the description of argument fixup in the manpage conveys this information to me only now that I have your example above to look at]. If I understand your comment, my odd-looking colours are a result of this mapping. So, how best to determine the maximum chroma for a given luminance and hue? -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
