A proper wallwasher has a specially designed optical system so that you can achieve even illumination on a wall from top to bottom and, where you don’t want a continuous run, wide spacings between the luminaires.
Obviously, you can achieve uniform illumination on a wall if the luminaires are a long way from it. The trick with a wallwasher optic is to produce an even illumination, top to bottom and side to side, when the fittings are mounted close to the wall. This technical information is sometimes presented as the height of the wall compared with the setback or offset distance. For example, a wallwasher with a 4:1 distribution could illuminate a 2.4m high wall from just 600mm away. Some manufacturers supply a spacing chart.
Similarly, the maximum sideways spacing between luminaires is often compared with the setback distance. Usually, it is the same, i.e. 1:1, but the better optical systems allow you to space the fittings further apart maybe 1.5 times the setback distance from the wall. Alternatively, a continuous run of linear wallwashers is a way of solving this issue.
You sometimes see luminaires described as wallwashers but are, in fact, designed to graze or skim the wall. These luminaires have very narrow beams, maybe as little as 10 degrees, and are mounted very close to the wall. The lit effect reveals the texture of the wall rather than illuminating the surface of it.
Another aspect to consider is whether you want the illumination all the way up to the ceiling. This can easily be achieved with surface mounted fittings but recessed ones will need to have a small drop-down “scoop” to project the light right up to the top of the wall.
What is sometimes forgotten is that there will always be some spill light on the floor. This isn’t normally an issue but just bear it in mind.
Of course, you can just as well illuminate a wall from below. The same geometry applies although spill light on to the ceiling, or towards the sky for outdoor luminaires, may be more visible. The ground mounted wallwasher would also have to be IP rated and more impact resistant.
It is worth mentioning that some luminaires described as wallwashers are just simple downlights with a built-in tilt. This does not give you as good a result as a true wallwasher but the reason involves quite a bit of trigonometry.
Create Lighting CLVO II
Create Lighting evolved from the long-established Crescent Lighting. They have been manufacturing high power LED luminaires for a quarter of a century so know what they are doing.
The CLVO has a huge range of options with colour temperatures, CCT, from 2500K – 5000K and colour rendering of CRI >80 or CRI >90 (available from 2700K – 4000K). Power ratings are from 27 – 54W/lin.m which, at this power, will emit over 4,000 lumens.
The standard unit is IP40 but especially interesting for outdoor applications is the IP68 submersible version which is resin filled and has a polycarbonate cover.
The best lens option for wall washing has a 10 degree beam which “skims” the light across the wall and works optimally with a very close offset distance.
This is a recessed unit which extends less than 40 mm into the ceiling. What gives the wallwasher excellent performance is the 14 mm 'drop down' which means the light reaches right from the floor to the ceiling. You don’t get a dark shadow near the ceiling which is a common effect with some wallwashers.
Although it is only 100 mm x 600 mm, it can deliver over 4,750 lumens in the 4000K, 28W version. It has a very broad vertical main beam which is emitted between 30 to 60 degrees. This gives therefore gives good uniformity over the main viewing area of the wall.
It is rigidly constructed from extruded aluminium and has a matt white finish. The bezel is narrow and super slim and it would be almost invisible in most locations.
The version we looked at is the wallwasher option from the Palco spotlight range. The wallwasher light distribution is achieved by using a snap-in spreader lens which directs the light more vertically. To this is added a lower scoop which blocks any rear emitted downward light. The upper half of the scoop is matt black.
An advantage of this track mounted unit is that it can be tilted to achieve high level illumination where it is most needed. The Palco wallwasher would be ideal in a gallery where you need a wide range of optical distributions that can be changed in situ.
For pure wallwash applications, there is the linear Laser Blade luminaire.
LEDFlex Flexi Grazer
As you might infer from the name, this is a flexible wallwasher. It is made from a clear silicone composite and is IP67 rated. The LED chip and asymmetric lenses are fully encapsulated and it would be ideal for illuminating curved walls either indoors or outdoors. The minimum bend radius is only 150 mm so you could also use it on large diameter pillars.
The peak intensity is emitted at about 15 degrees from straight down and this means you can mount the wallwasher quite close to the wall. Too close, and you can spot some striations appearing but it is better than most. LED Flex also have a very narrow symmetrical beam (15 x 15 degrees) and a wider (54 x 20) version.
The strip, itself, is quite compact, measuring 20 mm wide and less than 10 mm high.
Osram Linearlight Rigid Finesse
The wallwasher version is one of a wide range of linear, modular luminaires. You can have colour temperatures ranging from 2400K to 5000K all with a CRI >90. The indoor version is IP44 and the outdoor is IP67.
There are high, medium and low output versions, typically from 2,000 to 900 lumens/lin.m.
The beam is uniform without any striations but if I was being picky, the upper part of the beam is slightly warmer than the lower. This may be caused by the diffuser (rather than the clear) lens cover.
As well as the usual information, the datasheet contains lots of information about the colour spectrum of the LEDs. For example, as well as the Colour Rendering Index, CRI, the Colour Vector graphic and Colour Fidelity values from TM-30 are also given.
Trilux Oktalite Miova
A glance at the reflector system shows that the Miova will perform better than most of its rivals. The LEDs are hidden from view; even when you are standing directly underneath. The beam is reflected off a complex shaped profile and there are extra facets of satin aluminium to direct the light exactly where it is needed. It means you can achieve wide spacings and very uniform lighting.
Another feature is that as well as the usual 2700K to 4000K range of CCT, the Miova has a 3100K 'Best Colour'. This has a colour rendition of CRI 95 and includes saturated colours so that you achieve extra brilliance in retail environments.
There is also an 'Efficient Colour'. This has a CRI of 84 but delivers over 115 lm/W.
The recessed Miova, measuring just 300 mm x 50 mm, can emit up to 5,000 lm at 42W. Lower power units down to 2,000 lm and 16W are also available. There is also a similar surface mounted version, called the Twingle.
Urbis Schreder Sculpline
This comes in a variety of versions but if you want an outdoor IP66, impact resistant IK10, ground recessed (also available as surface mount), tunable white, wallwasher, the Sculpline can totally fulfil your needs.
The tunable white ranges from 3000K to 5700K. The single colour versions emit up to 6,600 lm per linear metre at 51W. Colour rendering is CRI 80 - 70. There are also RGB A and RGB CW versions. This choice means you can achieve just about any outdoor colour effect you want.
It is solidly constructed and has a very fine finish to the black anodised body. There is an optional downstand in locations where you want integral gear. This uses simple loop in/out weatherproof connectors.