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Courtesy of Toni Fresnedo. www.tonifresnedo.com
This emitter type projects light from the surface of a given object, so it is the whole geometry that is working as a light source. You can set the Color and the Intensity of your light separately. The color of the emission can be set in RBG, HSV or XYZ scales, correlated to a Kelvin value or from a HDR texture (emitting texture). The intensity (or Luminance) can be set in a number of different ways (see next section).
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Nit (cd/m^2). One “Nit” is one candela per square meter.
A note on Luminance type
It is important to remember that the amount of light emitted from an emitter is spread out across its surface unless you use luxes or luminance units which are dependant on the surface of the object.
This means that the same emitter material will look dimmer on a large emitting surface and brighter on a smaller emitting surface. You may also think something is wrong when scaling up your small emitter, since the amount of light falling on your subject looks like it has decreased:
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The two emitters are using the same emitter material. On the right, the emitter emits the exact same amount of light as the smaller emitter, but since it is emitting it over a much larger area, there is less light focused on the statue, so it appears darker.
If you would like to keep your emitter the same brightness no matter the surface, then you should use the lumens/m2 or cd/m2 units. Keep in mind though that this will actually change the amount of light emitted from the surface of the emitter when you change the emitter size.
Preset
Maxwell Render™ provides some emission presets of many standard type light sources. Please note these presets will change the color as well as the intensity of your emitters to match the light emission you are choosing.
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