On Saturday, September 8, 2018 at 9:33:21 AM UTC-5, Ivan Vegvary wrote:
Cut a very detailed threshold out of 1x6 oak board. As it turns out the color of the board is perfect complement to either room.
Question: What protective coating could I apply to prevent the oak from turning darker over time? Don't want shiny, would like to stay as matte as possible.
Thank you, Ivan Vegvary

Irrespective of what you do, some UV is going to get through and darken the piece. But Sonny is right, a good floor finish, with a high UV content, will keep it from darkening for the longest period of time.