Check the manual: "ADOBE INDESIGN CS6: SCRIPTING GUIDE: APPLESCRIPT"
One of the hardest aspects of scripting rules is discovering rule names and properties. Due to the dynamic
nature of rules (they really are just strings), specific rule names and properties do not appear in the Extend
Script Tool Kit’s Object Model Viewer. To discover this information, see “Exploring Preflight Profiles” on
.. and in the table that follows, you will find
ADBE_TransparencyBlending “ADBE_TransparencyBlending” on page 175
so on p. 175 you'd find this table:
Data Type Name Default value
Integer space 3
There is no list of values given, so presumably, the easiest thing is to set the blending using the Preflight panel to the item you want, check what value it is, and copy that value in your script for future use.
Thanks for pointing me in the right direction Jongware - it's much appreciated.
I concluded that setting the 'data value' of 'rule data object 1' to 2 (for RGB) or 3 (for CMYK) it works succesfully.
Example as follows (albeit rather verbose):
tell application "Adobe InDesign CS5"
set profileRef to object reference of preflight profiles whose name is equal to "ROBS TEST PROFILE"
set profileRule to object reference of preflight profile rules of profileRef whose id = "ADBE_TransparencyBlending"
set flag of profileRule to return as warning
set data value of rule data object 1 of profileRule to 3 (* RGB = 2, CMYK = 3 *)
I just now need to work out an elegant solution to handle all other properties.