When you buy a brand new brush (and oh isn't that great) remember to put it in some clear water for 2 or 3 minutes first...let it sit and soak up the water. Brand new brushes have a coating on them, it holds them together before use, so you need to release that first.
You will see when the brush has relaxed and soaked up some water, you will then be able to use it with your paints.
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