It can be hard to evaluate the ripeness of the pod visually, and I would rely on the condition of the pod more than I would the appearance of the seed. Sometimes the pod begins to change color from its ripening stage, to another color or shade as it begins to dry; pods with red coloration (such as Flamingo) often begin to show patches of purple as they begin to dry.

IMO the most reliable indicator of seed ripeness in beans is that the section of pod attached to the stem becomes weak & rubbery. At that point, the plant has cut off nutrients to the pod, and all that remains is for it to dry down. The seed is as ripe as it will get. I often harvest pods at that stage if extended rainfall is in the forecast (as it just was here) to avoid losing them to spoilage... those get placed in baskets under a fan, so they will dry before mold sets in.

Alternatively, if the seed pattern of shelled beans has darkened, I would assume that seed is close to maturity - the darker & more pronounced the seed color, the better. Dried down & properly stored, that seed should have good germination for at least the next year or two. How long it might remain viable after that is anybody's guess, but I wouldn't count on it for long-term storage.

Thanks Zeedman. That's exactly what I needed to know. I really appreciate your info, and generosity in sharing it.