ask this old house
Q Why does chalk-line chalk come in different colors? I've only used blue. PAT JONES, READING, PA. Different chalk colors A show up better on different surfaces, and they allow various trades to snap overlapping lines without confusing them. But the key difference between the colors is how long they stick around. Trim carpenters want temporary chalks, while roofers prefer ones that won't disappear in a downpour.