Face detection on B&W footage

I am testing out a workflow to use the "analyze for people" function to look through archive footage for people of interest (to the project).
Making a still gallery of the persons that I want to identify and analyzing them and naming them for the database.
Then I tried to analyze some 1939 B&W footage with almost no results even though HD quality and lots of people, how can that be ?
Working in documentary as an editor this would be a "to die for" tool when you have weeks of footage to go through. Finding real live footage of persons of interest adds a lot of production value to a project.

stay safe

I just discovered that when analyzing from still images there is no thumbnail representation in the "people window"
There is one thumbnail present in the attached png and that is from analyzing a sub clip of the 1 hour footage that I could not analyze with success before. Is there a length issue regarding analyzing for people ?
For me it makes sense if I can select the people that I want to search for

I am on Resolve 17.0B Build 27

Better move it to Resolve subforum, this here is for actual software development questions, as in using different apis etc and you won’t see much traffic here.