Why do colors look less saturated in shadow areas of outdoor photos?

Asked 5/9/2018

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In some outdoor color photos, the shadow areas look less saturated and often shift a bit blue compared with sunlit areas. Is this mainly because shadows are lit by skylight rather than direct sun, or is it also related to how color film records high-contrast scenes and how prints/reproductions were made? I'm trying to understand this lighting behavior for visual reference in painting/3D work.

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

8y ago

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You are examining color photographs that were made using a film camera. Consider that the typical sunlit vista has a scale (brightness range) of about 2000:1 or more. First, think about this, we can measures with a light meter the intensity of light being reflected by objects in a vista. Likely black automobile tires in shadow measure 10 Lux, whereas gleaming chrome measures 20,000 Lux.

Now we image this vista with a film camera. We properly expose and the film is properly developed and optimal prints were made. Also, you need to know that the unit of exposure used in photography is the f-stop. Each f-stop unit is symbolized as a 2X change. In that era and today, the typical range of light levels a film can record is about 10 f-stops. In other words, film typically can record a vista and the resulting film has a scale of 2x2x2x2x2x2x2x2x2x2=1024 (1024:1). Keep in mind, if we could make a faithful image of a sunlit vista, you would need to don sunglasses to comfortably to view this film

In that era (1960’s), it’s a sure bet, these films were made into prints on paper. Photo prints on paper are viewed by reflected light. We examine prints by means of a light playing on the print. This light transverses the dye, hits a white under surface, and returns by again transiting the dye. In other words, we view a print by seeing via two transits through the structure of the image. This takes a toll, and the best scale we can achieve is about 1:64 (6 f-stops).

What we are talking about is a compression of tone. The actual vista 2000:1 -- the film that recorded this vista 1024:1 – the print records the film as 64:1. The facts are, a loss of scale results.

Now the numbers are quoting are best case. The reality is, these images are less than perfect as to exposure and printing. Plus, if the prints are not on glossy paper, their scale drops dramatically. Now consider, the presentation you are viewing was likely made by scanning and digitizing prints, the film with its longer scale was likely long gone. You wanted to know why the shadow detail is lost. The images you are examining was made by imagining color prints that have faded because in that era we did not know how to make archival dyes.

The yellow dye, the one that should offsets the bluish cast had degraded the most.

Originally by user44949. Source · Licensed CC BY-SA 4.0

user44949

8y ago

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AI Answer

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It’s usually a combination of lighting and the recording medium.

Outdoors, sunlit areas are lit by direct sunlight plus some skylight, while shadow areas are often lit mostly by skylight. Skylight is cooler/bluer, so shadows tend to shift blue.

Shadows can also look less saturated because the scene may have more brightness range than film can comfortably record. A sunny scene can span a very wide contrast range, and film/printing has limited dynamic range. When exposure is set for the overall scene, shadow detail may get compressed, making colors in darker areas appear weaker or muddier.

With older color photos, reproduction and aging can add to the effect. Color film, printing, scanning, or later reproduction can introduce color shifts or fading, which may exaggerate blue shadows or reduce saturation.

So the short answer is: yes, blue skylight is a major reason, and film/print limitations and age/reproduction can reinforce the drop in saturation.

UniqueBot

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8y ago

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