A new tutorial video…Gradating a highlight using the Inverse Square Law.

Very often, I’ll place a highlight on the edge of something round. Of course, the highlight is on the “lit” side of the object, and so, the look of the highlight should indicate and be a result of the direction of lighting. In nature, when a hard light source is reflected on the edge of something rounded, the center of the highlight is brightest, and the brightness tapers off toward the ends of the highlight. Depending on various factors, like the reflectivity of the surface and the hardness of the light, this effect can be extreme or subtle. As in most of my work, I like to push things toward the dramatic side a bit. To that end, I employ one of the basic principles of lighting. Most photographers understand the inverse square law, which tells us that light falls off by the square of the distance. In other words, if we double the distance of the light to the subject, the amount of light is quartered. Put another way, if we move the light twice as far away, we lose two f-stops of exposure. This principle of lighting is often looked at in the negative (as a loss of something). In light painting, however, we use this principle to our advantage in several ways. This tutorial covers one of those ways.

Scales with light painted highlight using Inverse Square Law

Highlight on left using consistent distance………..Highlight on right using Inverse Square Law

So, in this image, I’m applying a highlight to the edge of a beautiful old scale. Below is a short video showing the application of the highlight in two different ways. In the first case, I’m keeping the distance of the light consistent as I go around the edge. In the second instance, you’ll see that I’m moving my light in an arc opposite the arc of the subject. This means that my light is closer to the subject at the center of the arc and gets progressively further away as I move through the arc away from the center. Light falls off by the square of the distance, so the center of the highlight is much brighter, and there’s a beautiful smooth gradation of light as we get further from that center point. Not only does this create the illusion of even more roundness of the edge, but it gives us a more dramatic indication of just where the light is coming from.

***Note: The video was shot with room lights ion so you could see the movement of the light. Normally, I am shooting in complete darkness.

This is one of a series of tutorials that I’ve created involving my light painting process, and it is just a quick look at the kind of information that my students learn more in depth at my workshops.

After the video starts, please click on the “gear” icon on the lower right to increase the video resolution for better viewing quality (1080 recommended)… especially if you want to watch it full screen.

To see more of my videos on Light Painting technique click HERE

~ by Harold Ross on March 17, 2014.

7 Responses to “A new tutorial video…Gradating a highlight using the Inverse Square Law.”

  1. […] A new tutorial video…Gradating a highlight using the Inverse Square Law…… and more…. […]

  2. Harold Ross is one of the most talented and creative photo-artists I have ever met. My experience with his Light Painting Workshop was fantastic! Thanks Harold, John Faber

  3. Another game winning RBI—–and a Golden Glove award for the way you handle that little light. Great video, Harold.

  4. Great tutorial

    Sent from my iPhone


  5. Hello Mr Harold,

    Thanks for this video,a very interesting tutorial.

    Mario Mifsud

    Date: Mon, 17 Mar 2014 11:59:45 +0000 To: mariomifsud781@hotmail.com

  6. Thank you for the video and sharing your technique.

  7. Thanks everyone! I appreciate your positive feedback!

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