We rewatched 3.9 because it was so interesting and we'd been half asleep last time.
Black and white on Better Call Saul are clearly ... black and white. Now, anyway. Dunno if they were doing that from the start. Darker and lighter work the way you'd think, too. If you watch the ladies Jimmy works on you'll see their clothes darken - and see green start to show up. Black starts to appear on him, as well as moral-ambiguity grey.
Breaking the law is red, but you don't have to be bad to break it, or to be breaking it to be bad.
Oilman's truck was green, and Kim's folders, but the show doesn't seem as committed to green - I don't think Jimmy wore any despite having cash-signs for eyes the whole episode. Though green's one of the ones I mess up most often.