Always a problematic thing, the comparison of painting with photography, or the other way around, should you prefer.
From my own experience I find it somewhat difficult to hang paintings and photographs on the same wall; the same room seems to work, but certainly not the same wall. Likewise, there are further problems when trying to hang colour photographs beside b/w ones. In the first instance, even good photographs seem somewhat inferior to paint and in the case of the second condition, there is an undeniable lessening of the b/w power when in battle with colour. (But see the later paragraph.)
However, and a big however at that, when either medium is hung independently, it becomes a very different matter and the ordinary habit of grading images according to perceived value/quality flicks into play at once. Each set of groupings seems to be better off when shown on its own.
The best way of showing a mixed selection of colour and black and white photographs is, in my particular set of circumstances, to separate them by devices such as mirrors.
Subject matter too makes for either balance or otherwise; I have a mixture of nude (b/w) and landscape (colour) and there´s no doubt that the nudes instigate instant comment from people not over familiar with the room. That includes female visitors, and none of the remarks so far have been negative. On the other hand, there has been no comment at all about the colour landscapes which means that they are either not worthy of nice words or are simply overpowered by the girls (on the wall).
Funny old world, but that´s how it goes down!
Rob C
