Quoting barbara beardsley:
I've planted Black Krim and Aunt Ruby's German Green tomatoes for the first
time, how do I tell when they are ripe? Some of the Black Krims are reddish
black with green on top, the German Greens are all dark green. What do these
types look like when ripe?

ARGG will go from a whitish green, then on to the darker green you
describe; finally it will start showing some amber undertone, with
just a bit of a darker blush on the bottom around the blossom scar.

What you've described for Black Krim sounds about right.

Both of these are fairly juicy tomatoes and should feel like it when
you squeeze them gently. If they don't feel quite ripe to you, they
are probably not.