Quote from Ontario F&W Conservation act
Hunter clothing
15. A person who holds a licence to hunt or trap shall, while hunting, wear coloured clothing in accordance with the regulations. 1997, c. 41, s. 15.
Hunting regulations summary general section quote from pg 23
Hunter Orange
The objective of the hunter orange regulation is to maximize
hunter safety without negatively impacting hunting success.
Under this regulation, all licensed hunters, including bow
hunters and falconers, hunting during the gun season for
deer, elk or moose, are required to wear hunter orange. This
requirement does not apply to persons who are hunting migratory
game birds, except woodcock.
In addition, all licensed black bear hunters hunting during the
open season for black bear are required to wear hunter orange
except when in a tree stand.
Where there is a gun season for moose, elk, or deer concurrent
with an open black bear season, then the only persons
exempted from wearing hunter orange are migratory game
bird hunters as indicated above.
A hunter orange garment and head cover must be worn. The
hunter orange garment must cover a minimum of 400 square
inches above the waist and be visible from all sides. Open
mesh or camouflage hunter orange must not be part of the
400 square inches. A hunting coat or vest generally meets this
requirement. The hunter orange head cover may have: open
mesh; a peak or brim colour other than hunter orange, and
a crest or logo which does not completely cover the hunter
orange on the side where it is affixed. The head cover must not
contain camouflage material.
Hunter orange colour standards are generally consistent across
North America. Manufacturers can provide information
regarding clothing compliance with this standard.
As a best practice to protect hunter safety, hunters using ground
blinds should take steps to make their blind clearly visible to
other hunters that may be in the area. Use of hunter orange
material on the outside of the blind is an appropriate method to
mark a ground blind.