PORTLAND, Maine — Dr. Henry Pollard was a dentist. He was also a photographer who built himself a darkroom in the bowels of his Danforth Street home. His children called it his bunker. It’s where he would disappear for hours at a time, developing pictures and playing his violin. Pollard’s darkroom was also where he kept secrets nobody would know about until after his death in 2003. While cleaning out Pollard’s inner sanctum, his children found four cigar boxes.