Wilhelm Kray (1828-1889) - Lorelei and Igorne (18xx) (upscaled and colorized)
I previously posted a black and white version of this picture here, saying "I'd really like to find a bigger, preferably colour, version of this picture, but unfortunately..."
Well, since then I've been able to apply online upscaling and colorization software to the problem, and here's the result.
IMPORTANT NOTE: Unlike the "colour recombination" method I've employed in the past, this online colorization is done from scratch, without reference to an actual colour source. Therefore the colours you're seeing here are purely speculative, and fairly limited in this case. Nevertheless, I don't think they look too bad, and anyway, in the absence of the original, they'll have to do.