Local tone, to state it simply, is where a painting is "local" color. ie not corrupted by light or shadow. A snowy day, a rainy day or a cloudy day with diffused light coming in. The lack of light flattens the objects down and value is the relationship. There are three values in local tone: Dark, Medium and Light. The medium will be closer to either the light or the dark. In the example below, the sky is the medium and it is tied to the light. Even though this example has shadow in the snow, it is still lighter than the medium and if you squint, the shadow still reads with the large snow shape. In local tone you should have a "base" shape. The base shape below is the dark group or the trees with the house.
In the paintings I am doing for this project, the base shape is the medium group. I have started three as I feel ambitious and I like local tone; I will post them as I get them done. Correct me if I am wrong, but do you get tired of seeing the painting progress? ie multiple postings of the painting as it takes shape or would you like me to post as works in progress?