Does the oxygen palette have a brightness peak? about cmocean

[kthyng]

Glad you like them!

The oxygen colormap is designed for use near river plumes, for example, where there may be very low and high areas of oxygen. The bottom 20% of the colormap, colored red, is to indicate hypoxic levels of oxygen. It is meant to be essentially from black to white in gray scale but with a red hue in that lowest 20% to show the important area, though in order for the red to be noticeable at all it was necessary to have a small jump in the grayscale version — so this was a trade-off. The lightest gray color is meant to correspond to 100% oxygen saturation, so that is your peak lightness. The final 20% of the colormap goes back down in lightness and is colored yellow to indicate another change: super saturation. These choices have been made in consultation with a couple of researchers, but there are some trade-offs. I think if low and super saturated oxygen was not a concern in an area, it would not make sense to use this colormap; it is meant to be scaled so that the hypoxic and super saturated areas align properly. Maybe all grayscale would make sense in that case, or something completely different.

I will add some details to the documentation to make this more clear.