I also think we can go by this hemospectrum for the troll Ocs' blood colors. v

[img]http://pre03.deviantart.net/b663/th/pre/f/2015/172/f/e/hs__fir3h34rt_s_hemospectrum_chart_updated_by_fir3h34rt-d69lc8q.png[/img]