Purpose of coloured, slanted lines on a seaplane

[Adam]

Hi Denes

They were much similar to the lines on dive bombers except were used in photography.

When the pilot/observer took recon pictures it was necessary to record at which angle they were taken for later analysis (ie, shadow length regulating building height, camo netting etc). Hence the lines below the cockpit were used to regulate the angles of the photography.

No doubt there will be more succinct answers to follow but in the mean time, hope this helps

regards

Adam

P.S. Can you post the link for that eBay auction please?