David Hayden Photography
Seeing the light; Part 2
Some links to previous articles discussing the exposure triangle and part 1 of this series on light.
Shutter Speed: https://www.davidhaydenphoto.com/post/speed-stills-part-two-of-the-exposure-triangle-shutter-speed
Seeing the light part 1 – What’s your angle?: https://www.davidhaydenphoto.com/post/seeing-the-light-part-1
All Light Has a Color.
In Seeing the Light Part 1, I discussed that all light (for photographic purposes) behaves the same way and has properties that that affect your images. If you read the previous article you know I ended with this image showing how the color of the light illuminating our subjects changes the color of our subjects.
A good example of this is the image at the top of this article and shown immediately below. This particular scene from Sangre de Cristo Arts Center presentation of the Nutcracker was lit with blue light for effect.
The image on the right is a color corrected version of the same photograph.
The Visible Spectrum of Light, a.k.a. White Light
The term “White Light” describes light that contains the full visible spectrum of light from infrared to ultraviolet.
It’s no secret the color of light affects our photographs. But it gets a little more involved. The visible light spectrum we can see is made up of millions of colors ranging from infrared to ultraviolet.
These two images directly below show the combination of colors that give us white light. The rainbow on the left is sunlight after passing through a prism.
The picture on the right shows some LED Christmas lights viewed through a diffraction gradient. For the most part these particular LEDs create the entire visible spectrum.
Not all lights are “full spectrum” though. Incandescent lights produce a yellowish color while standard fluorescent lights will give off a greenish or blueish cast and so on. The other part of the equation is the color of the subject we are shooting. The reason a green leaf looks green is because the leaf absorbs the bulk of the visible spectrum, but not green. The images below show what happens when full spectrum light reflects from a green leaf vs how green leaves look when the light hitting them only contains the red and blue lights of a grow light.
Our amazing brains.
An occasional problem we might run into as photographers is that our brains are so adept at adjusting to the light surrounding us that we don’t notice the tint. But, as soon as we review our images, we instantly see the color cast. I first learned this back when I was a kid. I would take a few pictures outside then later shoot indoors under incandescent light. The indoor pictures were so yellow by comparison! It was at this time I learned about color balanced film.
Color-balanced film is a type of photographic film that is designed to produce accurate colors under specific lighting conditions. Film is sensitive to a wide range of wavelengths of light, and the color of the light that the film is exposed to will affect the final color of the image. Color-balanced film is designed to compensate for this by having a color sensitivity that is specifically tailored to the type of light being used. For Example:
To give you a better idea of what I am talking about I took some pictures of a color chart under different lighting conditions.
The central image is a graph showing the range of colors that constitute white light and the range of the electromagnetic spectrum that is referred to as the visible spectrum. Specifically, it shows the range of light visible to human eyes.
In the center of the image is a set of 5 graphs showing the spectrum of light produced by various light sources starting with a warm spectrum LED on the left, a color balanced/tuned LED, and on the right, the daylight spectrum. The two graphs below these are color spectrums of a cool white LED and a repeat of the Warm spectrum LED.
The four color charts in the corners show the effect of the various light sources on the colors on the sample color chart. For all the images the camera white balance was set to “daylight.”
The upper left image was taken using filtered daylight coming from some windows.
The upper right-hand image was taken using a warm spectrum LED.
The lower left-hand image was taken using an incandescent studio light.
Finally, the lower right-hand image was taken using a white balanced Studio LED.
Even as I took the pictures, my eyes adjusted so quickly I barely noticed how the tint of the light was affecting what I was seeing.
Does the even matter when cameras have auto white balance?
Yes, it can matter. I have run into two problems using auto-white balance.
The first is, that it gives inconsistent results as the light subtly changes or the colors of the main subject change. We may not notice the subtle changes but as the auto white-balance works its magic trying to keep up with the light / color changes the images end up with a different color cast. When editing a series of images every image will need a slightly different correction in post to make the images have the same look.
The second problem I have run into is when the subject or scene has a dominate color as shown in the pumpkin images shown below.
I don’t know what is really going on, but it appears the camera sees the preponderance of one color and adjusts the image to bring it to a more neutral balance.
The image on the left was shot using auto white balance and notice the blueish tint, particularly in the glassware. Also notice how that blueish tint affected the warm color of the oak table giving it a greenish cast. The bluish tint was caused because I was using window light on a clear, blue-sky day.
The blue may be technically correct, but I wanted orange pumpkins and a more natural oak colored table. So, by changing the camera white balance setting from auto to daylight, the camera adjusted the image more to my liking. The daylight setting told the camera the light source was daylight so knew to balance the colors by reducing the blues and warming the image up a bit.
I shoot in RAW format so changing the color balance to meet my artistic intent is far more achievable. If I were to shoot in JPG format under extreme lighting conditions, it simply wouldn't be possible correct the colors I want..
A brief example of RAW vs JPG format . . .
The following four images give a good example of how the additional information in a RAW file allows for a much larger range of editing possibilities.
Using the exact same settings to correct the blue cast on bot the RAW and JPG files I get these results.
The images on top are RAW images converted from a dominate blue cast to a more balanced color rendering. The raw files have a broader range of colors consistent with the scene while the lower adjusted image has less color and dynamic range. The blacks in the JPG file have a blueish/greenish tint and are not black at all.
Coming next Sunday:
The third article in this series will be about soft and hard light, how to identify it and how to create it.
Comments