The upcoming April/May issue of International Artist magazine has a four-page feature that I wrote on reflections and transparency in water.
It covers the optics of reflection and refraction, transparency, the effects of turbidity, and tips on painting waves and foam. I wanted to write kind of a go-to mini-guide for the magazine's readers to have handy when the subject comes up.
One of the curious qualities of reflections in still water is that they tend to reflect vertical lines more readily than horizontal lines. This painting by Danish artist Peter Mork Mønsted illustrates the point.
The little branches on the far bank head in different directions, but it's the vertical branches that you see favored in the reflection.
The effect of elongation is increased with the strength of contrasts of the elements being reflected. Extremely bright lights, for example, are reflected in very elongated vertical lines. As 19th century British writer John Ruskin says,
"All motion in water elongates reflections, and throws them into confused vertical lines. The real amount of this elongation is not distinctly visible, except in the case of very bright objects, and especially of lights, as of the sun, moon, or lamps by a river shore, whose reflections are hardly ever seen as circles or points, which of course they are on perfectly calm water, but as long streams of tremulous light."
International Artist magazine website