Cause:

• Use of low quality paint
• Use of low quality tools or wrong roller cover
• Re-brushing or re-rolling areas that are partially dried
• Too much heat
• Use of paint not specifically made with good flow and levelling properties.

Prevention

• Dilute paint with correct ratio.
• Use the correct thinner to thin paint.
• Choose the correct roller and brush.
• Avoid painting under conditions that cause rapid drying of the paint.