Colors of Near and Distant Forests

October 09, 2015


Photographer: Mario Freitas; Universidade Tecnológica Federal do Paraná
Summary AuthorMario Freitas

The bluish appearance of distant objects isn't due to their true color, but rather to the effect of sunlight scattered by the atmosphere layer between the object and the observer. The influence of our atmosphere on the landscape was carefully studied in the 15th century by Leonardo da Vinci, who reproduced important visual effects in his famous Virgin of the Rocks painting. He noted that the longer the distance from the object to the eye, the more noticeable the contribution of the atmosphere. We know now, thanks to the electromagnetic nature of visible light, that strongly wavelength-dependent Rayleigh scattering on air molecules provides the increasing bluish hue while Mie scattering by dust particles results in increasingly whitish tones. Additionally, airlight decreases the contrast between near and distant objects.
In the above picture, taken from a cruise boat on Paranaguá Bay, Brazil, islands and mountains display near-to-far colors that shade from olive green to misty blue, although the type of vegetation growing on their respective surfaces is quite similar, all belonging to Atlantic Forests ecosystem. Just left of the out-of-focus boat knot, we see Pico Paraná, the highest mountain in Southern Brazil (6,158 ft or 1,877 m), which belongs to Serra do Mar (meaning Sea Ridge), dating from the Tertiary geological period and composed of granite and gneiss. Picture taken on August 1, 2015.

Photo Details: Camera: Panasonic DMC-FZ70; Focal Length: 16.5mm (35mm equivalent: 99mm); Aperture: ƒ/4.7; Exposure Time: 0.0016 s (1/640); ISO equiv: 100; Software: ACDSee Quick View.