Monday, May 30, 2022

Why Are Reflections of Bright Lights So Elongated?

Nina Garcia emailed: "The other day I was on a walk around my neighborhood pond when I noticed some interesting things about the view."



She continues: "I am trying to understand two things:
1. why is the light that is reflected in the pond so elongated compared to the reflection of the trees?
2. why does the reflected light go straight down (rather than away or towards a vanishing point if that makes sense)?"

Answer: In his 1903 book Light and Water: A Study of Reflexion and Color in River, Lake, and Sea, Sir Montagu Pollock uses this photo to illustrate an observation of reflections on gently rippled water: "The gentle movement of water in the distance elongates and exaggerates the upright lines of the buildings. In the foreground, the individual ripples become visible, breaking up the reflection of the mountains horizontally."

He explains the elongation of the reflection of the buildings by setting up a series of mirrors to represent the far wavelets, and then tilting them toward and away from the observer. Since the area they reflect shifts vertically, they have the effect of stretching the reflected image straight downward.

3 comments:

Jim Douglas said...

I wonder if masters of painting the impression of rippling water, like Zorn & Sargent, understood these principles. Or perhaps they just observed them with a very keen eye and represented them.

BCurrie said...

BCurrie
Hello James
Sorry to interrupt, but I suggest that the answer is incomplete: The trees do not get elongated because they are not reflected: they are dark, and therefore there are no photons to bounce off the waves. We infer the presence of trees from the silhouetting effect against the sky light. The tree silhouettes are not crisp and clear because the waves cause light scatter from light coming from a large area of sky.

Had the photo been taken in daylight, we would have seen the trees smeared across the foreground as usual

Best Regards

Manga&anime team said...

Thanks for repost the book!