at least one layer of liquid coating material comprising moving the substrate along a path through a coating zone providing one or more liquid coating materials in the form of a free falling curtain which extends transversely to said path and impinges on said moving substrate laterally guiding said free falling curtain by edge guide elements providing an edge guide fluid in contact with the free falling curtain and the edge guide elements wherein the edge guide fluid is an elastic liquid having a recoverable shear of at least 2 at a shear rate of 10 000 s u2212 1 as measured by means of a cone plate rheometer and comprising an aqueous solution of an organic polymer application_number US 44602507 A description in order to appreciate the subject matter of elastic fluids some basics of rheology will be summarized as follows unidirectional shear flow of a fluid is depicted in fig5 wherein v x denotes the velocity of the fluid in x direction and u03b3 yx denotes the shear rate or the velocity gradient in y direction the shear flow is described by three stress vectors u03c3 yx u03c3 u03b7 u00b7 u03b3 yx u03c3 xx u2212 u03c3 yy n 1 primary or first normal stress difference u03c3 yy u2212 u03c3 zz n 2 secondary or second normal stress difference in the majority of flow situations the secondary normal stress difference is not important for newtonian liquids both n 1 and n 2 are zero it is well documented in the scientific literature see for example u201c how to obtain the elongational viscosity of dilute.