When I first started my career, I was told by many Engineers that light planning is only a matter of calculation the light on working plane which is in most cases around 0.8m from floor level, which means planning the light only for horizontal spaces!Later I found out in most cases that light beams and scallops are more visible on vertical not horizontal which would make vertical as important as horizontal if not more important!For this guide the calculation and rendering was mad by DIALux evo software which is available as a free software from www.DIALux.com
This guide will help you plan the lighting by having proper offset to wall, grazing light (light scalloping) by different beam and offset, Uniform grazing light, Uniform wallwashing and Accent for objects on wall
Grazing (light scalloping)
Grazing light might not be the best option but when it is made it should be made right without making odd shape and destroying the space by weird light scalloping.To avoid bad light scalloping first you should know the following
- The difference between round and square downlight
- The beam angle of the luminaire
- The light distribution Quality (main beam and secondary beam)
- The effect of light with different offset from wall(distance from wall)
- The alignment of scallops with architectural lines.
- Intensity of lighting scallops
- LED Downlight with scallops.
The difference between round and square downlight
The light scallop of a round downlight is different from a square downlight
It should be noted that downlight with lens will make the beam softer.
The beam angle of the luminaire
The light distribution Quality (main beam and secondary beam)
Selecting the lamp and its optical system will make a big different scalloping result.It is always good to check the luminaire in real mock-up and use the correct photometric to get the same in reality.I have experienced many cases where engineers calculate from one manufacture and use specification of another one! , which could have completely different results.Lighting software like I will get accurate results only if right inputs are used and the most important parameter is selecting the right photometric.
The effect of light with different offset from wall(distance from wall)
The scallop size on wall will be affected also from the offset from wall (how far the center of luminaire from wall).Usually all offset when mentioned it means from center of luminaire, so in this Guide all offset are from center of luminaire to wall.The more offset from wall the lower the scallop from top of the wall as could be seen from bellow rendering.
The alignment of scallops with architectural lines
The lighting planner or lighting designer should understand the architectural space, if there is any lines , groves in the vertical then the lighting should be aligned to achieve good result, otherwise lighting could make scallops that not in line with architectural vertical lines
Intensity of lighting scallops
LED Downlight with scallops
LED is an efficient lamp source that is expected to replace all conventional lamp sources soon, however there are very different quality of LED ranging from very poor to excellent LED when it comes to scallop shape and color, so it is strongly advisable to check the downlight in a real physical mock.One of the criteria is how different in color are the LEDs (the different of white light from one LED to another) which called MacAdam ellipse or SDCM (Standard Deviation Color Matching)The products used for the next guide from ERCO has less than 2 SDCM which means no color visible to human eye.
Vertical Planner Guide for Grazing and Scalloping effect
In the following rendering I used some ERCO luminaire with different beam angle to show the different effects, all lamp source were LED and to ensure right planning, I made real mock up to see the difference between the scallop rendered by DIALux evo and the physical mock. The results of I evo were very accurate and ERCO photometrics were very precise as well.Unfortunately not all manufacturer provide precise photometric, so I strongly recommend to use well know manufacture for accurate photometrics and ideally should be tested in mock-up to achieve good results.
In the following guides which is called Vertical Illuminance Effects (VIE) I used offset and spacing as follows:All offset are from center of luminaire to wall,All spacing are between center of luminaires.
Uniform grazing light
Uniform Grazing is used to avoid the scalloping effect of light on wall and could be done perfectly with LED liner luminaire like ERCO Lightgap Luminaire.The luminaire in a cove of architecture in a continuous row.
Wallwashing is a technique that is makes the lighting design for a wall free from any bad scallops and enhance architectural, as a matter of fact I prefer this solution and find it much better than grazing light with scalloping effects simply because it shows wall clean and provide a sort of indirect lighting.
Accent lighting for abject on wall
Accent lighting is a very important and could be very attractive if done properly. It highlights an object and makes it an eye catcher ,But many people fail to make it right because not having the right offset for a spotlight to highlight a painting on wall.Close offset is common mistake which makes too strong lighting above the painting which makes it difficult to see the painting details instead of highlighting the painting
The VAG (Vertical Accent Guide), in the following guides for accent lighting, you can see different beam and different sizes of paintings for a ceiling height of 3 meter
VAG-5 and VAG-6 is using the same beam angle which is oval flood 15ox60o , however in VAG-5 the narrow side was facing the wall while in VAG-6 the wide side was facing the wall .
Lumen and Center beam of Spotlights
In order to make the painting attractive it should have more light by at least 5 times than the surrounding, this could be achieved by selecting the proper lumen of spotlight and also the center beam intensity of spotlight, using computer software ensure proper selecting of spotlight bean angle and intensity to make the object as an eye catcher.
Vertical Illuminate is very important during planing stage
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