Possible Clues:

• What a riddle for the cinema?
• Insect repellent?
• Investigate the 20s
• Carry out a security check and show the public a picture
• The riddle of the camera
• Onto which pictures are projected
• Cover - cinema
• ''Sun'' or ''smoke'' follower
• Show or hide
• It's a riddle how there can be so many holes there