Did it dry out too fast before it had the moisture to properly carbonate, or is the substrate just refusing to play along? Curious if the client is embracing the ‘character’ yet or if you're already dreading the scrape-back.

The second it leaves marks on a client’s dark coat, the romance is officially dead. If it's still dusting that late, the substrate probably drank all the moisture before the lime ever had a chance to properly carbonize.

If you walk away from a wall looking like you just left a bakery, the carbonation didn't take. That’s definitely crossed over into failure, sadly.

If it’s still shedding chalk onto your hands months later, the carbonation cycle stalled—usually because it dried out before the free lime could actually react with atmospheric CO2. Patina shifts tone and weathers, but a binder that never fully knit to the masonry is just an application failure.

If it’s still coming off on your palms months later, it dried too fast and never properly carbonised. Honest patina ought to stay on the wall instead of hitching a ride home on someone’s coat.