Any percent over 30 percentage points is encouraged, provided that the requirements of this Standard are met. A tolerance of 5 pct shall be allowed. When opened not less than 15 seconds or more than 20 seconds after sealing, the flap shall pull fibers from the body of the envelope over the entire adhesive area. The adhesive shall be able to resist the heat and pressure of common office laser printers, so the flap adhesive does not become soft and tacky causing the flap to stick to the body of the envelope. The envelopes in the order shall be uniform with a brightness of the white paper not less than 82 pct.
Standards are blue, buff, green, pink, salmon, or yellow.
Colors shall be pulp-dyed. When a match to a Government color standard has not been specified, the commercial standards for these colors and white are applicable. Color coordinates for selected standards are included in Part 3. Envelope stock shall have a wove finish. The dirt count for each side of the paper shall not exceed 250 specks per square meter.