"black colouration" is correct and usable in written English.
You can use it to refer to something's colour, either physical or metaphorical. For example, "The obsidian rock had an unusual black colouration that made it stand out from the others."
The only exception to colour morph changes occurring within nymphal stages are changes to black colouration, which have been reported to occur during the imaginal stage [ 14].
After incubation, colonies with black colouration were confirmed as typical Enterococcus cells.
Cephalopods - squid, cuttlefish and octopuses - change colour by using tiny muscles in their skins to stretch out small sacs of black colouration.
While the study does not mean that Archaeopteryx was entirely black, it does suggest that it had some black colouration which included the coverts.
Exhibiting a high degree of sexual dimorphism, the male in breeding plumage is a small, long-tailed bird of predominantly bright blue and black colouration.
Few drops of 0.1% ferric chloride was added and observed for brownish green or a blue black colouration as indication of tannins.
It is initially roughly the same colour as the cap, but as it matures, develops a wine-red colouration near the base and a sordid-brown to bluish-black colouration elsewhere.
Browrish green or a blue-black colouration indicated the presence of tannins.
Development of brownish-green or blue-black colouration was taken as positive for the presence of tannins.
A few drops of 0.1% ferric chloride was added to the filtrate and observed for brownish green or a blue-black colouration.
A few drops of 0.1% ferric chloride was added and observed for brownish green or a blue-black colouration an indication of presence of tannins.
