If it is a glass carrier, you need to get the dust off the two sides of the glass in contact with the negative. If it is a glassless carrier, I usually would put the negative in the carrier first, then try to get the dust off of it. You need to have a bright light shine on it and hold it at an angle to see the dust. Randomly brushing the negative just puts dust from the brush on the negative. You need to see each dust particle and remove it. I think a blower works better.
Originally Posted by baachitraka