1975 INTERNATIONAL COMMISSION ON IRRIGATION & DRAINAGE
25th ANNIVERSARY

September 30

Lithographed by APO - NEDA, Manila,
on five types of paper, in sheets of 50  subjects (5 x 10), 
Issued perforation 12 1/2. 
Quantity: 4,925,000 perforate sets and 75,000 imperforate sets.

In 1981, 1,500,000 pieces of 1.50p surcharged to 1.00p
and another 500,000 to 2.00p.
 
Normal 40s
Blue Color Proof
Normal 1.50p
Illustrated stamps from original printings, on ordinary paper with cream gum,
OO Type, which does not react to UV light.

Orange Shifted Down

Rose Shifted Up

Blue Vignette Essay

Printed on thin unwatermarked paper. Without gum.