Oh, now I got it! Well, Doyle, you seem to know me very well. I mean that about "this IS the natural coloring" ;-) But this time I have to say that it is the natural coloring only on some few days of July and then only from 14:00 to 15:00 or so. I was astonished last year to find out how quick the coloring changes as the days of the year are passing by. The blue is actually not only the blue if the water but a mixture of that, plus reflections from the buildings around the river. And the sepis, well that is only the reflection of the tower on the water - we have turquois water plus that baige-to-brown wall of the tower, and so the resulting color is quite sepia like.
But another thing about your idea. I'll try again this summer and take consideration of your explanations, I think it could be possible to do that according to your idea only with the camera and nothing else at all. I think it would get very nice!
I assumed, perhaps incorrectly, that these were not the naturally occuring colors. The left side appears to be sepia and the right side blue. The dividing line in the water feels very unreal. Perhaps you did nothing more than change saturation levels, if that, but the image feels worked and by fade I was referring to desaturating the blue towards the change line so it would feel more natural. Now I have this feeling you're going to tell me that this IS the natural coloring in which case any tepid advice I could give to make it seem more natural is foolish and I (clearly) was only kidding--That's my story and I'm sticking to it.
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