Uhhh....maybe you're thinking of Enterprise...Essex wasn't launched until July 31, 1942. Enterprise (CV-6) was Hornet's escort on the Doolittle raid from April 8-25, 1942.
Essex CV-9 arrived in the Pacific in May of 1943, but her first operation was in the Marcus Islands in August. At this time, she was wearing Measure 21, overall 5-N Navy Blue, and remained in Measure 21 until April of 1944. She underwent a refit in April of 1944 that altered her island structure, installed catapults on her flight deck, and increased the number of 40mm mounts. She then repainted into Measure 32/16d. She repainted back into Measure 21 in November of 1944.
Jeff