MaxSmoothness, MinSmoothness (user params)

This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP

Smoothness essentially controls the number of steps used to produce a shaded fill (traditionally called a vignette). Some applications set smoothness to a value which will not produce good results. In this case, vignettes are constructed in a way which reveals very noticeable banding. Typically, the creating application can be set to use a more sensible default value, however this can be difficult in some workflows. For this reason, the user parameters MaxSmoothness and MinSmoothness have been created to override problematic smoothness settings. They allow Harlequin RIP users to set sensible override values.

This can be set in a page feature or as part of the code in the HqnOEM startup file.

<< /MinSmoothness .001 >> setuserparams

In MultiRIP, setting MaxSmoothness in HqnOEM would not be effective as it would always be overridden by the Minimum shaded fill levels option in the page setup, and setting it in a page feature would override the setting in the GUI, causing some confusion.

The MaxSmoothness param sets a limit which controls the minimum number of steps that can be used in constructing a vignette. This is important in ensuring vignettes do not have banding.

Note that there is an extra divide by 2 when calculating the MaxSmoothness value from the number entered into the GUI for Minimum shaded fill levels. For the default value of 256, the calculation is 1/256 x 1/2.

MinSmoothness sets a value which reduces the risk that the smoothness can be too fine and thereby affect rendering time.

These user parameters limit the numeric value set by the setsmoothness operator in PostScript and the /SM ExtGstate key in PDF.

The default values for these are not likely to have any positive effect on the rendering of most files. OEMs or users must implement other values to have these parameters impact their workflows.

The default values are:

MinSmoothness = 0.0002

The MaxSmoothness value is product-dependent and OEMs are advised to determine and set a suitable value for themselves.