"How to distinguish a good brush from a bad one, what should one pay attention to?"
It is not customary to put a glass of water near the counter, as brushproducers recommend not to wash off the protective layer - gumming, that is why it is really difficult to determine brush quality. One should check the presence of the bar-code. If there is no bar-code or it is not clearly delineated, it can be a sign that the quality is not so high.
If it is an artist brush, a brush head is to be gummed. (gumming layer is easy to remove by rubbing a brush head slightly with fingertips. If a brush is high quality it will take the original form after getting wet.)
Protective tube is to be clear.
Compare two brushes of one series. The more distinctions you see the lower quality is. One should pay attention to the crimping and to the very tip of the handle.
Of course there should be a label on the handle, the color is to be identical even of unpolished handles. Catalogues with the brushes description should also be available in the shop.
Probably only specialists can determine the quality of the hair, security of attachment and approximate life span of the brush, but even if you consider these points you can protect youself from buying bad quality fakes.
