Hi Greg:
Yes, the yellow features of the hull (lettering and stripe) become more prominent in later photos because the film in the 30's was far more sensitive to the yellow-orange-red part of the spectrum than film from the turn of the century. Hence, this is an artifact of the photography, not because the color changed.
Notice that the Cunard Line's funnels (orange) appear black or dark grey in many photos in the 1910's but "lighten up" considerably in the 1920's.
Bill Sauder
