Clean the logs thoroughly if they aren't new. Scour them with concrete cleaner, using a scrub brush. Rinse them with fresh water and allow them to dry.
Sand previously painted logs lightly with a medium-grit sandpaper.
Place the logs on plastic sheeting or a painter's drop cloth.
Prop one end of each of the logs on wooden blocks so you have access to all sides.
Paint the logs with a coat of high-heat barbecue primer, using a paintbrush. Allow the primer to dry.
Paint the bark part of the logs with dark brown high-heat barbecue paint.
Paint the core sections of the logs with light brown or gold-yellow high-heat barbecue paint. Allow the paint to dry for one hour.
Apply a second coat of paint to the logs. Allow the paint to dry for at least 12 hours before reinserting the logs in the fireplace.