Lidibean, I think this quite possibly leaf scorch from unwanted strong sunlight. I have seen this happen to Fatsia in south-facing directions during the winter months when trees defoliate. Fatsia is definately a shade lover.

I put your pics in "My Pictures" file so could magnify them. I don't see a golden-yellow halo around the scorched area that might indicate fungal infection, such as Colletotrichum leaf blight. (This one and many other fungal infections don't follow the common pattern of circular brown spots with a gold halo). Also, the red areas in your second pic appear to be the beginning of over-exposure to intense light - so the chlorophyll (green leaf pigment) is destroyed exposing anthocyanin beneath (violet-red pigment).

To rule out possible fungal infection, check to see if there are black and/or white fruiting bodies in the dead leaf tissue. This might require a magnifying glass. Spider mites also cause extensive damage to leaves, but I don't think this is the case.

thanks john z!

since i have moved the plant inside the browning seems to have stopped, so it must be due to sun. i appreciate the feedback!