Ignore me; I just found PD4Constants.PD4ML_MEDIA_TYPE_PRINT

public static final java.lang.String PD4ML_MEDIA_TYPE_PRINT

“pd4ml.media.type.print”. PD4ML by default interprets “screen”, “all” and “pdf” CSS media types. If the parameter is set to “add”, it adds to the list “print” media type. If it is set to “override”, it forces PD4ML to ignore “screen”, but use “print” instead.

See Also:
PD4ML.setDynamicParams(java.util.Map), Constant Field Values