How to prevent light-colored macarons from browning? I have a problem with baking yellow macarons, or any light coloured macarons. 

The yellow (or any light colour) ones always brown, always! 

I tried lowering the temperature, I bought the best colours I can get in the UK. The colours are powdered, to reduce the liquid content. 

Does anyone have a method they could suggest that is fool proof.
As well as the previous answers and if not already doing so, try using beet sugar (e.g. Silver Spoon in UK) rather than cane (e.g. Tate Lyle in UK)
as beet sugar takes a little longer to Brown.