Does a skeleton dial need a darker background to make the hands stand out?

Hand finish matters more than people give it credit for. A polished hand on a polished bridge is rough no matter what color the background is. Dauphine hands with brushed flanks and polished edges can catch light even over a bright movement, but it depends a lot on the lighting you're usually in.

Darker background definitely helps contrast, but I don't think it's strictly necessary. Some skeleton dials use a frosted or grained finish on the main plate that scatters light and keeps the hands readable without going full black. The texture does a lot of the work.

For me the bigger issue is busy-ness behind the hands.

A dark background can also make the whole watch look flatter and less interesting if you actually want to see the movement. I've passed on a few skeleton pieces because the smoked plate hid too much of the finishing. Legibility vs. showing off the movement is a real tradeoff.

northshorekev has a point. If there are a lot of bridges and wheels right behind where the hands sweep, contrast alone won't fix it. Fewer overlapping components in the center area seems to help more than just going dark.

I have a skeleton with a bright rhodium movement and blued hands. The blue reads very well against the silver, so a dark plate isn't the only way. Color contrast between hands and movmeent can work too, but it's harder to pull off and depends heavily on the hand color.

The other thing is the hands themselves. Skeletonized hands look great in Photos but can vanish in person. Solid hands, or hands with lume, tend to read better than openworked ones no matter what the background is.

Lume helps a lot in low light, but a lot of skeleton watches don't bother with it. Without llume or good polishing, a dark plate only gets you so far.

I hadn't thought much about hand finish and the amount of stuff directly behind the hands. That makes sense, especially the point about openworked hands. I'll pay more attention to how the hands are finished next time I'm looking at photos, not just the background color