You might wish to make the corpus self-expanding, and for a given word do Wikipedia (or other source) lookups to see whether structured information on the colour exists.
There are whole lists of colours on there: https://en.wikipedia.org/wiki/List_of_colors:_A%E2%80%93F
Of course, it would require the addition of attribution for wherever you obtained the data.
Oh, and welcome to subjectivity... battleship grey, it's changed over the years but the commonly accepted one is the WW2 era grey which featured a touch more blue and is RAL 7031 ( http://www.ralcolor.com/ - which btw, is another source ).
PS: And it doesn't know the difference between blood and dried blood.