In the present results from a program of near-IR scanning of planetary nebulae, the observed flux is in most cases dominated by free-free emission. In three of the nebulae, dust excess continua at K are comparable to free-free emission, although there appear to be no significant changes in source size between the J and K bands. Profiles in IC 418 are strongly variable, changing in width by a factor of about 2 between 1.2 and 3.6 microns. Attention is given to the thermal balance of grains in IC 418, as well as to the optical properties of grain materials required to maintain high dust temperatures. It is found necessary to postulate grains of radius as small as 0.001 microns, with low thermal capacity, or grain materials with anomalous optical properties.