Does anybody know how to set quality = Prepress

[Luterson]

I am trying to reduce the slight jpg compression fringing around bit mapped lines produced by the default "standard" quality of pdf conversion.

However, the following Excel VBA does not seem to have any effect...

' after ensuring that "References > Bullzip = ticked"
Dim myobject As New Bullzip.PDFPrinterSettings
With myobject
.SetValue "Quality", "Prepress"
End With

...even though lots of other Bullzip parameters can be set in this way.