Hi Mark,
I'm not able to answer the color question definitively other than to say that photos indicate it was not blue, at least not a dark color like 5N. Tracy White probably has some documentation for the wartime color of overheads visible from outside the ship. He may have some pre-war documentation, too.
The pre-war photo below taken of sistership
Hornet CV-8 in November, 1941, may be helpful. To my eye, the overheads all look to be painted the same light gray as the vertical bulkheads. But, the overheads could be white in shadow.
Attachment:
CV-8 1941.11.19.jpg [ 156.02 KiB | Viewed 3967 times ]
My Essex class and
Saratoga CV-3 references are better and may provide some clues to how the overhead areas visible from outside the ship were painted during wartime. Those references indicate the overheads were painted white. Perhaps
Enterprise CV-6 wartime overhead color reflected the same directives as the Essex class. Photos of
some, but not all, of the Essex class show that the white color was carried down from the overhead onto the exterior vertical bulkheads a bit, probably as a counter-shading measure.
Notice in the photo of Essex class
Yorktown CV-10 that the white counter-shading extends down the transverse girder supporting the flight deck. The white stops about the bottom edge of the longitudinal girders.
Attachment:
CV-10 1944.10.06 Ms 33 10a.a (2).jpg [ 755.23 KiB | Viewed 3967 times ]
But the same girder on sistership
Hornet CV-12 does not appear to be counter-shaded, likely 5H or 5L from top to bottom.
Attachment:
CV-12 1944.05.29 021232.jpg [ 105.97 KiB | Viewed 3967 times ]
Also note that, generally, the hangar deck bulkheads forming the elevator wells of some but not all wartime ships were painted blue, probably because those areas were visible when viewed from the air when the elevators were lowered. This appears to be the case on the photo of
Enterprise in December 1942 posted by Rick Davis and reposted here:
Attachment:
CV6x34-25Dec42.lr.jpg [ 260.15 KiB | Viewed 3966 times ]
But in this photo of
Enterprise in 1941, the bulkheads appear very light, perhaps light gray, maybe even silver.
Attachment:
CV-6 1941 98633651.jpg [ 691.12 KiB | Viewed 3965 times ]
In this wartime photo of
Essex CV-9, there is both blue and gray (white?).
Attachment:
CV-9 Essex Hangar 01.jpg [ 49.64 KiB | Viewed 3963 times ]
It appears that colors changed, and frequently.
Hopefully Tracy or Rick can provide more information about
Enterprise CV-6.