  This paper, originally motivated by a question raised by Wood and Hanna [Soft
Matter, 15, 2411 (2019)], shows that pure measures of bending for soft plates
can be defined by introducing the class of bending-neutral deformations, finite
incremental changes of the plate's shape bearing no further bending. This class
of deformations is subject to a geometric compatibility condition, which is
fully characterized. A tensorial pure measure of bending, which is accordingly
invariant under bending-neutral deformations, is described in details. As shown
by an illustrative class of examples, the general notion of pure measure of
bending could be of use to formulate direct theories for soft plates, where
stretching and bending energies are kept separate.
