Blanco is the colour white but it has other uses in Spanish (as do green/verde and Black/negro) and I thought starting a thread could be useful here are a few expressions off of the top of my head, please feel free to add more and discuss the use of colours in expressions in there languages too if you'd like to :)
Dar en Blanco- hit the mark (to succeed at something the first try or with ease)
El dardo dio en el blanco... the dart hit the target
Pasar el noche en blanco- sleepless/restless night
Quedarse en blanco- when your mind goes blank and you can't think of what to say
Ir de punta en blanco- Is to be dressed smartly, formally out of the box or off of the mannequin you would go to a job interview punta en blanco :)
we also use 'estar sin blanca' if you have no money
and you can be' en el blanco de criticas (the butt of the joke)