Deep and Pale Ultramarine
The different OB positions would indicate that a single hand pressed OB device was used.

1913 MAY 6: MANILA to BAGUIO
2c Rizal green on buff Constabulary size 7 official envelope dispatched via Special Delivery,
20c fee paid with 1911 issue with hand pressed black OB.
Black Page 1
Black Page 2
Black Page 3
Red Overprint >>>