Having just about finished a prolonged episode of domestic painting I've twigged that undercoat (matt) is mainly pigment and not much resin whereas gloss is the other way around. I imagine Satin is halfway in between - logically. Probably the same rule applies to all paints.
BTW If it's of any use to fellow decorating sufferers, Dulux Trade is brilliant stuff to use; expensive compared with DIY store stuff but what a difference to apply!
Colin
Cleaning an airbrush is dead easy. Spray mucky thinners through until it clears, then spray clean thinners, inverting the airbrush to clear the pickup tube. If it's a brush with external mix, then unscrew the nozzle and spring and chuck the whole lot into a jar of clean thinnners. Swirl it around, then take it out and dry it. Takes longer to describe than do. Once in a while, strip down the brush and run a pipe cleaner soaked in thinners through it. If it has a needle, take that out carefully and clean it with an ink-eraser rubber. One thing you MUST NOT DO is leave any part to soak in thinners. It can (and probably will) swell the rubber O ring seal and b****r up your brush.
Suit yourself...........but you knew I'd say that anyway.