In the Houdini colorbar HDA under "color options", set the menus like this...


Details:

png file /svs/share/houdini/cbars/images/png/solar-rgb.png
tex file /svs/share/houdini/cbars/images/tex/solar-rgb.tex
definition /svs/share/houdini/cbars/definitions/cmocean/solar-rgb.csv
credit Kristen Thyng
reference https://matplotlib.org/cmocean/