Evaluating the Color of Light and the Properties of Lamp Reflectors

Every light bulb produces light in a spectrum of light that will either highlight or hide what you are looking at. In order to better understand how to best choose a light that is right for the application that you are working on, consider the following points of thought.
Lamp Color
This is the light that you see, and it is made up of the wavelengths of visible light each lamp type produces. For instance incandescent lamps have a continuous spectrum in all visible wavelengths of light. Picture a graph showing the different visible color spectrum wavelengths starting with dark blue on the left, and as you move to the right you move into light blue and the lighter colors of yellow and then red. Plotting incandescent lamps on this graph would be to draw a line from the bottom left corner where dark blue is, to the top right corner of the graph where light red is. So with an incandescent lamp you are getting a whole spectrum of color that has very little blue and a lot of reds and yellows.
High Intensity Discharge Lamps (i.e.: Metal Halide, Mercury, and High Pressure Sodium lamps) when plotted on the same graph have spikes of highs and lows scattered along the length of the graph.
Fluorescent lamps have a continuous light spectrum that looks like a large arc going from left to right on the graph. It starts low on the blues, curves high on the yellows, and then curves low again on the reds on the graph. It also has little spikes of visible light wavelengths along the arc.
Continuous full spectrum light sources produce less distortion of objects than do line or band spectrum lamps. This is because they are able to bring out all the different colors that are present in a space. High Intensity Lamps are great for spotlighting an object or surface to bring out a particular color within an object.
The Optical Properties of a lamp
If you want better control of your light source you want to choose one that is smaller and more compact, meaning your light source (i.e.; the filament) is as small as it can be. Incandescent lamps are the most compact light sources because they have the smallest filament. In contrast fluorescent lamps are more difficult to control because they are large sources. Depending on the way an HID lamp is made, it can either have a large source or a small controllable source. Just remember small means more control, and large means less control of the light being emitted from your lamp.
Optical Characteristics of Reflectors
When a reflector in a light fixture has a smaller light source, it will have tight beams of light, that create a greater contrast between the light emitted and shadow of the object you are highlighting. The light from a small light source will strike an object with very few angles creating heavy shadow and light contrast. But when using a larger light source, the beams of light are more sporadic and scattered; giving the light less direction and increasing the number of angles the light is striking the object. Because of this there is a softening of the contrast between the light and shadow on the object. Think of it this way. The light of the sun is the largest light source there is and as it floods the earth with light it is striking objects with light from many different angles making shadows lighter and softening the effect of shadows and objects.
After looking at these points, look at the area you are designing and ask yourself. How does the lamp color, its properties, and its reflectors affect your design? Are you trying to have a strong light presence with deep shadows or are you looking for something soft, which blends the area together. Hopefully these tips can help you to develop the best lighting design for you.

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