Are there standards for density cutoffs, colours and colour mappings for electrostatic potential surfaces?
I observe that people use many different values. For instance, this article (in Fig. 1a) uses 0.001 au density cutoffs with colours ranging from blue (< 0 kcal/mol) to red (> 20 kcal/mol).
I understand that not every colour/energy range will work every time, but other publications/websites even switch the colour range. This website, for instance, uses red for negative energies and blue for most positive ones. Furthermore, the same website suggests a .02 au cutoff.
Are there recommendations on this? Which values are more commonly used by textbooks?