Hi, we engaged Dulux and their appointed painter to paint Dulux Ambiance for our home. However, after about 6 months, whitish substances started appearing on the walls. We wiped it off but the whitish substances reappeared not long after. Hence, we asked Dulux to come down and take a look. Upon inspection, the representatives said that this problem is quite common and not restricted to Dulux paint but the other brands too. They said that the problem was due to the wall materials and the ventilation issue and has nothing to do with the paint and the paint application. Their advise was to leave the windows open at all time. Only problem is that there is no one at home and what if it rains. hence, it seems we have no choice but to bear with the whitish substances. According to Dulux, the whitish substances are not harmful. Would like to find out if others have faced the same problems with whitish substances appearing not long after painting.