One of the most common assumptions contractors make is selecting chalk color for
its visibility. While being able to read chalk lines against a colored work surface is important,
it is not the only consideration. The type of surface material, project type, and location should
also be factored in.
Blue is a good, all-purpose chalk that is easily removable when not applied to a porous surface.
It's suitable for framing or hanging drywall because blue is easily distinguishable on white or
off-white surfaces. Most trim and interior work is marked in white chalk primarily because it will
not stain interior walls, carpets, countertops, or floors.
When working outside in the elements or with materials like concrete and metal, permanence is the
top priority. Once popped, black or red will make a sharp, long-lasting mark that will not rub or
wash off, making either color ideal for subfloors, parking lots, or roofs. Remember to keep both
of these products far away from finish materials.
What about dark workplaces? White and blue chalk is nearly impossible to see in the low light of
basements. That's why many electricians and plumbers choose fluorescent orange, fluorescent green
or yellow chalks because they practically glow in the dark.
But low-light areas are not the only use for these non-traditional colors. Orange, green and yellow
can also be used to differentiate contractors' marks, allowing anyone to easily follow plumber's lines
without mistaking them for electricity lines. When the plans for a job have changed, which is known to
happen in construction, having more than one color to re-mark an area comes in handy.