see rule 12-2:

12-2. Identifying Ball
The responsibility for playing the proper ball rests with the player. Each player should put an identification mark on his ball.
Except in a hazard, if a player has reason to believe a ball is his, he may lift the ball without penalty to identify it.
Before lifting the ball, the player must announce his intention to his opponent in match play or his marker or a fellow-competitor in stroke play and mark the position of the ball. He may then lift the ball and identify it provided that he gives his opponent, marker or fellow-competitor an opportunity to observe the lifting and replacement. The ball must not be cleaned beyond the extent necessary for identification when lifted under Rule 12-2. If the player fails to comply with all or any part of this procedure, or if he lifts his ball for identification in a hazard, he incurs a penalty of one stroke.
If the lifted ball is the player’s ball he must replace it. If he fails to do so, he incurs the general penalty for a breach of Rule 12-2, but there is no additional penalty under this Rule.
*Penalty for Breach of Rule 12-2:
Match play — Loss of hole; Stroke play — Two strokes.
*If a player incurs the general penalty for a breach of Rule 12-2, there is no additional penalty under this Rule.

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Gord

Quote of the month:
"It's easy to see golf not as a game at all but as some whey-faced, nineteenth-century Presbyterian minister's fever dream of exorcism achieved through ritual and self-mortification." ~Bruce McCall