Old but good explainer of logic on using color averaging, then picking proper blending, which is automated currently bypasses an easy explanation of logic

"The Golden Gate Bridge," Morrow wrote, "is one of the greatest monuments of all time. Its unprecedented size and scale, along with its grace of form and independence of conception, all call for unique and unconventional treatment from every point of view. What has been thus played up in form should not be let down in color."