Pemaquid Group of Artists will demonstrate plein air—that is, outdoor—painting at the “Open Lighthouse Day” event, 10 – 2 p.m. on Saturday, Sept. 15 at Lighthouse Park, Bristol. The Open Lighthouse Day is a celebration of the “Open Lighthouse Day”and its historical significance. Admission to the park during the celebration will be free to the general public. Local artists and members of the Pemaquid Group of Artists will be painting on the site during the event and will be happy to answer questions from observers. Refreshments will be served to visitors at Pemaquid Art Gallery, which will be open for its customary hours of 10-5 p.m. For more information, call Pemaquid Art Gallery at 677-2752 or visit pemaquidartgallery.com.