I don't know what you mean by fall color. These plants are the color they are from spring to winter.

Partial shade is 6 hours of sunlight. Would they get that?

As for Dogwood it can be planted in full shade. My neighbor has 2 in the front of his north facing house. They are variagated white with green edges and it does very well there. Another nice shrub for the shade and your climate is snowberry. small white spring flowers give way to white berries and some of the newer varities have pink berries and berries.

They will be fine. Dogwoods don't really like lots of sun, actually. Ninebarks do fine anywhere, I find.

Fall colour depends on many things.

I find Snowberries are powdery mildew magnets.

The ninebarks won't develop as rich of a color...the Darts Gold will probably be greenish. They may tolerate it..they just won't thrive.

By fall color, I mean for example, Dart's gold is a green-yellow early in the season and turns a brilliant orange in the fall. I was concerned that without enough sun, the shrubs would thrive but wouldn't develop the beautiful autumn colors we're looking for. In my opinion that is such a waste! The bed where I ws going to plant them doesn't get 6 hours of sun, maybe 3-4 hours of morning sun only.

That would be fine for dogwood but in my opinion not for the ninebark -You fave full shade not partial shade. While Ninebark would probably survive there it wouldn't thrive and you'd probably compromise the colors. There are not many shrubs for your zone and shade, but there are lots of varieties of dogwood though so why not try a few of them. For instance the grey dogwood or Cornus Alternfolia has white berries in the summer and turns red in the fall. It would look lovely with the variagated white and green leafed one.

My mom in-law has a Dart's Gold that barely gets any sun and does just fine.

I don't think shade in the afternoon would be a problem.

Shazam, does her Dart's Gold change color in the fall? If so, how intense is the color?