Possible Clues:

• Merchant takes up colour painting
• In business one might turn the colourful painting over
• One will get the ruddy craft back for 24 across
• Merchant ship putting back port light with skill
• One selling Soviet craft to the west
• He's back to deal with the ruddy painting
• Tarred like merchant
• Dealer rejected Russian paintings
• Revolutionary painting returned by dealer
• Is it his business to turn red with craftiness?