This question has been answered with advice from Astro Lighting Ltd.
The first principle to bear in mind is that you do not light the mirror itself. The way that we see the world around us is a result of light bouncing off surfaces, scattering light in all directions – some of which reaches our eyes. As we move around something, every slight movement brings a new stream of photons into the eye. However, there is one surface that doesn’t play according to these rules – the mirror.
Whereas other surfaces allow reflected light to scatter in all directions, the mirror acts in a very singular way. The angle at which a light beam hits the mirror is equal to the angle at which the light bounces from it. And 100 per cent of the light that strikes the mirror is reflected – no light ‘sticks’ to the mirror surface, so there is nothing to see of a mirror surface (dust and fingermarks apart).
What we generally mean when we ask how a mirror should be lit is, ‘how should I provide lighting to the area in front of the mirror, so that the person looking into the mirror can see themselves properly?’ And that’s a much clunkier question to ask.
When you stand in front of a bathroom mirror, light leaves your face, heads towards the mirror surface and then bounces back towards you. We want to see our face clearly, so the face needs to be surrounded by a soft, shadow-free light.
This means that the light needs to come towards you from the mirror. Ideally, the most effective lighting solution will illuminate both sides of the face to ensure an even, flattering glow, with no shadows.
The least effective – but also the most common – is a light from the ceiling above, such as a recessed downlight. These lights were not designed to illuminate above the wash basin, but their relative simplicity, size and cost means they are an inevitable lighting solution in many applications.
If you are limited to a central ceiling solution, make sure that the light comes from a soft diffusing surface, such as a white opal glass.
If you already have downlights above your bathroom wash basin, there are a couple of ways you can improve the lighting without making any radical changes. Fortunately, there are downlights that are fitted with diffusing front glasses. These are far better than suffering from the illumination coming from a bare downlight lamp.
You’ll also find combined mirror lights, with illumination set into the mirror surface itself.
These can be very efficient and have the added benefit of being easier to keep clean.
For a more in-depth guide, refer to Astro’s bathroom lighting guide.
To see other lighting questions answered by experts, click here.