Introduction
Wher producing a haif-tone colour reproduction it is important that the colour separator.proofer and printer have previously specified a minimum set of parameters that visual characteristics and other technical properties of the planned print product. Such an agreement enables the correct production of suitable separations (With recourse to "trial and error")and subseguent production of off-press or on press proof prints from these separations whose purpose is to simulate the visual characteristics of the finished print product as closely as possible
it is necessary to distinguish between primary and secoridary parameters.Whereas primary parameters,which are described in this part of iso12647,are defined here as having a direct bearing on the visual characteristics of the image,secondary parameters only influence the image indirectly by changing the values of primary parameters Secondary parameters include.
-colour separation film thickness
-film polarity (negative or positive)
-roughness of the emulsion surface
-presence of colour marking or register marks