  Users of the JKTEBOP code to solve the light curves of eclipsing binaries
often confuse the gravity darkening coefficients, $y(\lambda)$, with the
bolometric gravity darkening exponents, $\beta$. JKTEBOP requires the
wavelength-dependent coefficients. I show that the numerical values of
$y(\lambda)$ and $\beta$ can be rather different, leading to potential biases
in the solution if the wrong quantities are used.
