How long does it take for dulux trade mid sheen vinyl silk emulsion to dry to its final colou?I ask this question as last week i painted the front half of the lounge with this paint in magnolia,today i painted the other half from a a new tub of paint,after 12 hours todays coat from the new tin is a darker shade than last weeks paint,does this just require more drying time or is it a case the shades from 2 tins wont match each other??