I touched on the quality of light a bit in my earlier post "Let's take portraits - 7 tips for improving your portraiture" but in this post I'd like to talk about light in more detail. It's a big topic but I will try to present it as simply as I can.
Light is light is light. There are many different sources of light, but the source of light is much less important in photography than the quality of light. This means that if you understand how to manipulate the quality of light, you can use different sources of light to achieve a similar look. You don't need expensive strobes or perfect weather conditions to get "good light" (or more accurately, the light you want for the photo you envision taking).
There are many different ways of describing light, including hard / harsh, soft, direct, indirect, warm, cool, tinted, mixed, and feathered. This is by no means a complete list - and I don't know if there is even such a thing, but I think it's enough to give you the vocabulary needed to communicate your thoughts on light.
Hard / harsh light: Light that is "hard" or "harsh" describes light that creates hard or harsh shadows - in other words, the transition from light to dark is abrupt. Usually this is from a bright and small source of light. The sun at midday in a cloudless sky, bare strobes, flashlights, and bare bulbs, are all examples of harsh light.
In the photo below, see how the shadows have clear lines? Every crease on the subject's clothes, every contour of a person's face, results in clear shadows. Harsh light is good at defining edges. The trade-off is that it creates shadows (often unflattering ones) across peoples' faces, highlighting and exaggerating wrinkles, eyebags, sunken cheeks and other features.
Soft light: Light that is "soft" describes light that creates soft shadows - in other words, the transition from light to dark is gradual. Usually this is from diffused or reflected light. The uneven surface of the reflective material scatters rays of light in various directions. The scattering results in softer shadows. Similarly, any material that diffuses light shining through it can be used to create soft light. So you can be as creative as you want (or need) to be, to get soft light. You can bounce light off walls, styrofoam, white board, or reflectors. You can shine light through soft boxes, umbrellas, curtains, or sheets of paper. All of these will work to create soft light.
In the photo below, notice the gentle transition from light to shadow across the subject's jaw, neck, shoulders, arms, etc. The soft light flatters features instead of exaggerating them.
This soft light could have been created from any number of sources, such as sunlight bouncing off a wall or shining through curtains, or from shooting a strobe through a large octobox, or from bouncing a flash off a reflector panel.
It is up to you to assess the environment and circumstances, and figure out how to craft the light you want with the resources available to create the image you envision.
First principles
Hard and soft light are probably the two most important qualities of light that you will keep coming back to over the course of your journey as a photographer. So this is a good point at which to introduce some first principles.
The hardness or softness of light is determined by the perceived size of the light and its distance to the subject.
The larger your perceived light source, the softer the light.
The smaller the perceived light source, the harder the light.
The closer the perceived light source, the softer the light and the more contrast and fall-off.
The further the perceived light source, the harder the light and the less contrast and fall-off.
Perceived light sources
Why do I stress perceived light source? Because it's all about perception of size. The sun is an easy example - it's a HUGE light source, and yet on a clear day it behaves like a small light source, giving us harsh shadows under our eyes, nose, and cheekbones. Why is this? Because it's so far away that it looks like it's only an inch wide in the sky. In other words, its perceived size relative to a subject here on Earth is only 1 inch. So the takeaway here is that it's not about how big the actual light source is - it's about how big the light source appears to be, relative to the subject.
Fall-off and the Inverse Square Law
"Fall-off" refers to how quickly the intensity of the light diminishes. We all know that as light gets further away from the source (i) it seems to become less bright, or less intense; and (ii) it tends to "spread out" and illuminate a larger area.
This is described mathematically as the Inverse Square Law - light intensity decreases at a rate inversely proportional to the square of the distance between the subject and light source. This illustration shows how the Inverse Square Law works better than I can explain it:
Source: Borb / CC BY-SA
Let's assume you've got a light source S and the subject is a piece of paper at a distance of 1m (r) from the light. At this distance, a lot of the light from S hits the paper (see all the light rays penetrating the paper at 1r?).
At a distance of 2m from the light source, the light has spread out and covers a larger surface area - 4 pieces of paper. Notice that each piece of paper has less light rays penetrating it? That's because each piece of paper individually receives less light - 100% of the light divided by 4 pieces of paper = 25% of the light. This is why the papers are not lit up as brightly - the light intensity has decreased from 100% to 25% on each piece of paper.
At a distance of 3m from the light source, the light has spread out even more and covers 9 pieces of paper. Each piece of paper individually receives even less light - 100% of the light divided by 9 pieces of paper = 11.11% of the light. So the light intensity is even less.
So the Inverse Square Law tells us the light intensity at each distance. "Fall-off" describes the decrease in light intensity.
Between 1m and 2m, the fall-off is 100% - 25% = 75%. In other words, the paper at 2m is 75% dimmer than the paper at 1m. But between 2m and 3m, the fall-off is only 25% - 11.11% = 13.89%. This is a much smaller difference in light intensity.
So the takeaway here is that the closer you are to the light source, more fall-off there is. In other words, you go from high to low light intensity very quickly, which results in more dramatic contrast. Conversely, the further you are from the light source, the less fall-off there is. In other words, the change in light intensity is much less drastic, resulting in less contrast.
You don't need to memorize the Inverse Square Law, but you should be familiar with the first principles above, as they will help you create the quality of light that you need - not just for controlling how you want light to illuminate your subject, but also how it impacts your background - because now you know that if you double the distance between your background and light source, the background will get 4 times darker.
Other ways of describing light
Direct light: "Direct" light describes light that shines directly on the subject. (E.g. where your subject stands directly in the sun)
Indirect light: "Indirect" light describes light that reaches your subject indirectly (e.g. where your subject is lit by light bouncing off a reflector)
Warm light: "Warm" light describes light that contains warmer colors such as reds, oranges, and yellows. Warm lights can be created from warm light LEDs, Edison bulbs, lights shining through cellophane that tints the light a warm color, bulbs that shine through cream or beige colored lamp shades, golden hour, etc.
Cool light: "Cool" light describes light that contains cooler colors such as blues. Cool lights can be created from cool light LEDs, the blue hour (twilight), lights shining through cellophane that tints the light a cool color, etc. Bright cool light that is unpleasant is sometimes described as looking "clinical".
Together, "warmth" and "coolness" of light is called the "color temperature" of light, and is measured in Kelvins. Warm light is usually in the range of 1,000K - 4,000K. Cool light is usually in the range of around 6,000K - 10,000K. "Daylight" or "normal" light is usually in the range of around 4,000K - 6,000K. Flashes and strobes are calibrated to be in the daylight range to try and provide a neutral color temperature.
(L-R): Warm, Normal, Cool
Tinted light: "Tinted" light describes colored light. You can color light using "gels" (colored filters), taping colored cellophane to a flash, or really any kind of colored filter through which light shines. In the photo below, the tinted light was from colored LEDs shining a cool bluish teal on the left and a warm orange on the right.
These LED light sticks can change color - perfect for artsy atmospheric lighting. My friend Adam (great photographer, check out his IG) and I spent an evening experimenting with them and went through a bunch of color combinations including a very Christmassy green and red combo.
Mixed light: "Mixed" light describes lighting conditions that are mixed, and usually where it involves different color temperatures appearing within the same scene or photo. Mixed light can be artistic and fun if intentional (like the photo above), but tricky to manage and correct if it is unintended. For example, you may be shooting a photo of an office space with a mix of daylight coming through windows and warm office lights from the ceiling. If you calibrate the color temperature of your photo so that the daylight looks white, the office lights will look too orange. If you calibrate it so that the office lights look white, the daylight will look blue. Weddings and events are also common scenarios where you may encounter a mix of warm and cool light, or mixes of colored light. Here is a real-life example:
These photos are from my friend Sara-Ann's beautiful Midsummer Night's Dream-themed wedding in Penang. It had so many stunning visuals, with candle light, a glowing moon, hanging gardens, and rays of light shining through the mist. It was magical. It was also full of mixed light.
On the left, the image is calibrated such that the white spotlights and rays of light are white, but doing this makes the image too warm because of the candlelight is warm by comparison to the spotlights.
On the right, the image is calibrated so that the white candles are white, but doing this makes the image too cool because the white candles are actually illuminated by the orange glow of the flames, so the spotlights are blue by comparison.
In the middle, I try to strike a balance. Neither the candles nor the spotlights are truly "white", but when they are balanced together, they bring to mind the magic and mystery of a warm candles glowing in the cool moonlight.
Feathered light: "Feathered" light describes light that is pointed slightly in front of the subject instead of directly on to the subject. Because the light is angled away from the subject, the perceived surface area of the light source is actually smaller, so the light is potentially harder. But because it is angled, it spreads across the subject more, giving a potentially more pleasing look.
I hope this article was a useful introduction to light and that it helps you be more mindful of the light that you're shooting in. Once you are sensitive to the quality of lighting conditions and know how light works, you'll be able to adapt to almost any kind of condition by changing your location, angles, distances between the subject, background, and light sources, creating and using new or alternative light sources, and modifying the quality of the light!
If you find these tips useful, please consider sharing your photos with the community by tagging #dharmaportraits on your Instagram photos - I'd love to see how you're using these tips to create beautiful photos.