why does my nail polish develop tiny bubbles as it is drying?

Bubbles may be caused by insufficient drying time between coats. If polish does not dry thoroughly between coats, solvents can push up through the top coat, forming tiny bubbles. Bubbles may also form when polish is applied too thick. The solvents will not evaporate as quickly as they should and will be trapped under the next coat of polish, forming bubbles as they try to escape. Also, vigorous shaking of the polish bottle creates bubbles in the bottle and are picked up by the brush and then transferred to the nail. Always shake bottle gently or roll between your palms. Any influence which makes polish dry unevenly can also cause bubbling (for example, high humidity, low room temperature or hot sun).