The new leaf opens in the early morning, before you've made coffee. It is the color of a wet penny — burnished, slightly translucent, with the midrib still pale and the lamina hanging like soft leather from the petiole. By afternoon it has darkened a shade. By the third day it will be the deep matte green of an adult Anthurium papillilaminum, and you will have forgotten what it looked like when it was new.
Most growers treat that flush of color as a bonus, a flash of decoration that ends when the leaf hardens off. It is not decoration. The bronze, the wine red, the dull cocoa brown a leaf wears for its first seventy-two hours is a readable signal — about pigment chemistry, about light, about the plant's health and its history. Learn to read it and you will catch problems a week before they show up in the older foliage, and you will understand why two seedlings from the same pod can look like different species at eight months old.