Best aluminum grade for high gloss black anodising?

Hey

Im currently looking for a way to improve my black anodised parts. At the moment we are using AL 5083 for our sheet metal parts and the results are quite inconsistent. We have a very high rejection rate and we want to improve this. Is it possible or likely that it is down to the type of aluminium we are using? The parts have to be high gloss black and be perfect as they will be very visible. At the moment some parts are coming back from the anodisers dull.

From research i have found that 5083 might not be the best to use. What would be more suitable? From looking online some people are saying 6463,6060 or 5005 might be better but are these available in sheet? Would changing alloy bve a likely remedy to the problem?

Thanks guys

Chris