Monday, September 12, 2011
Hard light or soft?—09/12/11
How to determine which type of light is right for your shot.
|This Article Features Photo Zoom|
A specular light source is also called a hard light because of the hard-edged shadows it creates. Think of the sun on a clear-sky day: the light is a pinpoint light source without any clouds in the sky to diffuse and broaden the source. The shadows the sun creates are distinct and hard edged, with a higher contrast range between shadow and highlight. This is the nature of a specular light source, and if you know how to put it to use it can make your photos more interesting.
To enhance texture on a subject—say, the cracks in pavement or the wrinkles on an old weathered face—the ideal light source is a hard one. Because of the hard-edged shadows a specular source creates, it’s perfect for enhancing texture and showing every last bump or imperfection. This has long made portrait photographers afraid of hard light sources—because they don’t hide blemishes and wrinkles in skin. But photographers who want drama—even portrait photographers from Hollywood’s golden era—know that specular lights create contrast, and that ups the drama of a still image. They just have to be placed deliberately because of the strong shadows they create.
To minimize a subject’s texture—let’s say you want to make a portrait with soft skin that hides every blemish—a diffuse light is the ideal source. That’s why portrait studios are filled with those broad softbox light modifiers. Instead of a pinpoint light, these diffusers spread the source over a wider area, softening the edges of shadows and filling them in to minimize contrast. Sure, diffuse sources can be used in a number of ways to make them varying degrees of hardness (moving a large softbox very far from the subject, for instance, makes the light appear proportionally smaller, and therefore less diffuse) but they’re the perfect place to start for photographers who want to minimize texture in their photos.
Some objects have specular and diffuse qualities too. A shiny silver spoon, for instance, has a specular surface because a pinpoint lightsource shone on it would reflect an equally pinpoint highlight. Photographing these surfaces is very tricky if you don’t know what you’re doing. The trick with specular surfaces, however, is to never photograph them with specular lights. Use a diffuse light source on a specular surface to create a pleasing highlight on the shiny surface. With these surfaces you’ve got to remember that you’re not lighting the surface itself, rather you’re lighting what that surface sees. What it sees when working with a diffuse source is a broad, even and pleasing illumination that reflects beautifully on a specular surface.
A great rule of thumb for deciding between a specular source and a diffuse one is to consider the overall effect desired in a photograph. Do you want increased drama? This comes from contrast—the contrast built in a hard-edged shadow from a specular light source. Hard lights like this might not always be pleasing, but they do up the drama. That means you can change the overall mood of an image, and its effect on an audience, just by understanding the differences between hard lights and soft, and how they interact with different surfaces and textures.