@todd
I’m not sure I understand … my English is bad.
The shape detection algorithm is complex and is based on color discrimination. In the case of black and white it is obvious that there are no more colors!
Some topics nevertheless will work because the algorithm is less selective (eg CBDL, Blurr …).
For others (Color and light, Retinex …), it is necessary to increase scope, to escape a detection too selective
:).