  Analyzing two standard preparators, the Stern-Gerlach and the
hole-in-the-screen ones, it is demonstrated that four entities are the basic
ingredients of the theory: the composite-system preparator-plus-object state
(coming about as a result of a suitable interaction between the subsystems), a
suitable preparator observable, one of its characteristic projectors called the
triggering event, and, finally, the conditional object state corresponding to
the occurrence of the triggering event. The concepts of a conditional state and
of retrospective apparent ideal occurrence are discussed in the conventional
interpretation of quantum mechanics. In the general theory of a preparator in
this interpretation first-kind and second-kind preparators are distinguished.
They are described by the same entities in the same way, but in terms of
different physical mechanisms. In this article the relative-collapse
interpretation is extended to encompass also preparators (besides measuring
apparatuses). In this interpretation also the mechanisms become the same and
one has only one kind of preparators.
