"The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow." - LEONARDO DA VINCI

Light and shadow have been mutual overtones to each other from the beginning. Depending on the context and application, one gets importance over the other. There is nothing called shadow free lighting but only shadowLESS lighting.

An open plan office or airport pre-check in area full of shadows and a luxury showroom or restaurant which is uniformly lit are examples of misplaced priorities between light and shadow.

Quality, position and orientation of shadow is a function of light intensity, direction and distance. We have seen the impact of shadows on our perception in my blog " Can we see LIGHT?"

This is the typical context of shadow that we are used to but let us widen the context of shadow with the help of the definition by Leonardo da vinci and 'City lights Asia' photograph from NASA.

In this Photo, We see a single source of light, the sun and the object, the earth, receiving the sunlight. There are no external obstructions but the object, by itself, is an obstruction which casts a SHADOW on itself. 

In relation to the areas with higher lighting levels, the areas with lower lighting levels is said to have shadows. It follows an inverse square fall off.

The same object without the shadows and darkness appears dull and flat.(being earth, it is never uninteresting!)

Let us consider the example of Airport Lighting. Instead of considering individual areas, like pre-check in area, security etc, let us consider the entire terminal building as the object. The object itself has walls/partitions which act as obstructions. So there will be areas with higher lighting levels and areas with lower lighting levels. Instead of random lighting levels, a systematic falloff is highly desirable. 

Instead of individual light fittings, imagine a single light source in the center of the Airport!. This way we can visualize the light falloff from the center towards the land side and the air side.

In an airport, the passenger flow route determines the fall off. Since the flow is on two directions, the fall off is symmetrical. In cases of an office or a restaurant or hospital, the falloff, typically, would be asymmetrical. 

Figuratively speaking, it would be a noon sun for an airport, rising sun for an office or hospital and a setting sun for a restaurant!

It is worth mentioning color temperature falloff, Warm to Cool, in the same context. It might not be this symmetrical, though.

Obviously, highly varying lighting levels and luminance within the same volume of space might be acceptable in very rare cases. But, it is highly beneficial, when there is variations in lighting levels and luminance between volumes of spaces. But with a systematic falloff, instead of sudden variations. 

It would make our ciliary muscles and iris to get some exercise! It would transform dull and monotonous spaces into interesting, lively and healthy functional spaces.

Jerry Maguire would have said " Shadow completes Light!"

What do you think? Share your comments below.

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I aim to spread awareness on the subject of Healthy Lighting designs to facilitate co-creation of healthy lighting at home, work and other social spaces. My posts can be accessed at Archinect  and Linkedin Group. I also have a self published book "Healthy Lighting of your Homes" at Amazon.