What color is Photograph, Photograph of the Construction of a Mass-operational House Designed by Hector Guimard (No. 7) ?

Source Crayola® CSS3 CSS4
#373633
 
#414a4c
outer space
#2f4f4f
dark slate gray
#2f4f4f
darkslategrey
#575347
 
#414a4c
outer space
#556b2f
dark olive green
#556b2f
darkolivegreen
#827c6f
 
#757575
sonic silver
#808080
grey
#808080
grey