What is spot lighting and why is it so popular? It’s time for some insights. Many general lumiaires are ‘all-round’. Meaning that the light is evenly distributed not only downwards, but also upwards and sometimes also to the sides. That is a good thing, because light ceiling and walls bring a spacious feeling tot he room. At the same time will the diffused light from the ceiling bring a softer image with less shadows and contrasts.
In case you want good light on certain places and still keep an intimate atmosphere with less ambient light, you need to install more focused light. Imagine your kitchen island at home, or adding accents to cupboards, walls or art pieces.
Downlights and spot lighting use reflectors or lenses to direct the light in a nice distribution. On the spec sheet it often states ‘spot’, ‘medium’, or ‘flood’. That is the width of the beam, also indicated in degrees (°). Below 20° is often considered as ‘spot’, over 40° we speak of ‘flood’. But this exact figure doesn’t mean there is a hard cut-off. So how do we determine the figure that indicatest he beam width?
Here you can see a photometric curve (light distrbution curve) of a recessed spot. The yellow indicates how much light is emitted in all directions.
In the centre of the beam the light intensity is at the maximum, that is 100%. Now if we move away tot he side untill we measure a light intensity that is 50% of that maximum, there is the point that gives us the beam width. In this example it is approximately 40°. You can see most of the light is emitted within the 40° range, but not all of it. How the edge of the beam looks like in real life differs for every fixture. Sometimes you want a sharp edge for a dramatic effect. But most of the time a soft gradient is desirable to blend nicely with the other spots that are close.
(in the picture: Modular Semih)