---

Colin Ball, lighting director at BDP looks at how both energy saving and consideration for human biology are driving more nuanced light levels in workspaces

---

EDITED BY JILL ENTWISTLE

DARKNESS IS an important tool for lighting design. It’s akin to a composer using a ‘rest’ in their musical score to denote silence. This phraseology is very suitable for lighting too, as darker, warmer spaces constitute a psychological rest for our eyes as well as for the melatonin cycles of our brain. We are all now aware that our phones can keep us awake at night.

Reflective materials and darkness create a balance with daylight that can promote healthy circadian rhythms and reduce carbon consumption. Image Credit: SANNA FISHER-PAYNE

Much has been studied and published in recent years concerning productivity and concentration in the workplace, how brighter ceilings and cooler temperatures improve well-being. This is defined as quantifiable melanopic lux ratios in WELL Standards, complex jargon for a simple fact: our eye/brain system evolved to be awake under a sky and to contemplate around a warm fire, prior to sleeping in darkness.

Reflective materials and darkness create a balance with daylight that can promote healthy circadian rhythms and reduce carbon consumption. Image Credit: DONAL MURPHY

We have noticed a gradual shift across the lighting industry in recent years where the bright, optimistic drama of colour and showpieces of previous decades have subtly evolved into a calmer, internal warm glow, as evidenced by nearly every stand at the last Frankfurt Light and Build exhibition in 2018. A form of lighting that is perhaps encapsulated by the Danish word hygge for the calmness of feeling the moment. In English this is close to mindfulness, although this word loses the tone of intimacy and of being with others.

This inviting glow from within depends on darkness to frame it, and on allowing that warmth to glow out. We have seen dramatic client and user responses to schemes that use darkness as an energy-saving device to meet carbon zero or exemplar targets. This means using daylight where it was available and only using artificial light to balance contrast. The dramatic discovery occurred when these daylight spaces were allowed to darken down and we found that our clients did not want them brighter. Rather, they appreciated the warm ‘business class’ mood of their interiors.

Transforming the windows as black reflectors is another contrivance we use to meet the increasing preference for dark, warm and absolutely black finished spaces in many of our interior lighting designs. An intentionally dark space – that you can comfortably navigate and read where you wish to – still sets many design challenges, but the comfort of the eye and balance of vertical contrast takes precedence over light levels. We are now using our restaurant and hotel experience to inform lighting office suites across the city. Our evening light setting is crucial to a comfortable working environment. This is only likely to increase now that Covid-19 has dramatically domesticised our working day and changed our human demands.

The atrium of UCL’s new student centre is designed to be an effective space in both daytime and evening settings, when the windows transform into black mirrors. Image Credit: TOM NIVEN

The increased density of screen time at work, for leisure and on our phones, increases the amount of time each day that we stare into the cool blue strobing light that keeps us stimulated and concentrated. The need to balance this is also increasing – future places for work and leisure need to offer quieter, warmer and darker spaces as an alternative to still being ‘on your screen’. As a profession we need to reinforce the desire to return to group, collaborative working without a digitised intermediary.

Cambridge Assessment’s HQ uses reflective surfaces to emphasise the ever-changing daylight. Image Credit: PHILLIP VILE

The following projects are examples where our team has successfully designed in a darkness element and illustrates how this trend has been developing in recent years.

An intentionally dark space within the workplace has traditionally been associated with a place to present, where attention is concentrated on to a single speaker. Dating back to Wagner’s demand to darken the auditorium during performances, we culturally accept sitting in dark spaces akin to theatres. This is apparent when the auditorium or meeting room is the sole dark space in the environment. Around 2018, using evidence we gathered from carbon reduction techniques, for the first time we had a compelling reason to persuade our clients that less light was better.

the library at the Digby Stuart campus at the University of Roehampton uses small pools of light to create a different feel when the space is used at night. Image Credit: TOM NIVEN

The ability to model daylight helped to counter the intrinsic fear our clients had that a dark space was a negative space. By asserting that reducing carbon consumption and promoting natural healthy cycles are positive reasons to use darkness, we were able to reduce quantities of light fittings. We took this further, using reflective materials and darkness to act as natural balances to the ever-changing daylight.

The impact of light pollution on the natural environment was another important consideration. Image Credit: TOM NIVEN

The images of LDN:W and UCL illustrate that taking this approach means very few light fittings are visible within the threshold and atrium spaces of the building. The key was to allow these spaces to be read ‘at night’ in their evening settings, exploiting the transformation of the windows into black mirrors. Where occupants are working or reading, their pool of light remains local within the dark environment.

The techniques for lighting any change of level or requirement for reading become very localised. Contrast ratios need to be emphatically controlled – any glare will disturb the occupant’s vision, hence vertical accents and reflected light from materials become far more important at lower light levels. This means that all items can be seen even in low light and create a sense of safety. Fear of tripping or of not seeing are averted.

PwC’s headquarters in London contrasts dark walls with a bright, animated central area. Image Credit: PHILLIP VILE

Light pollution is well understood in external designated areas for natural conservation, particularly relating to bats and astronomers. We have worked closely with both and discovered the exponential sensitivity of the eye at very low levels of light. These 1–5 lux environments have taught us how to comfortably manage the eye’s adjustment range from light to dark. It is worth emphasising that if you have met conditions for a dark environment, it does not matter whether you are inside or outdoors, your eyes function in the same way. We now employ lighting techniques in workplaces that are appropriate through each stage of the 24-hour occupancy cycle; we understand the triggers and impacts that can stimulate or relax personnel at different times of the day. We can safely light exterior spaces down to 5 lux with the right balances, and at the right times we can also do this for our interiors. Presentation spaces with intentionally dark interiors need to be entered via a slow, gradual passage to enable adjustment without temporary blindness. Dark peripheral spaces that control the gradual progression help to achieve this.

It is interesting to note that we can now confidently darken spaces to slow occupants and attract them away from their bright, cold, flickering screens from the moment they enter the reception. As discussed at the beginning, the need to relax and de-stimulate our eye– mind system elevates the importance of contrast-controlled techniques throughout every aspect of our interiors.

Contrast ratios needed to be controlled in reading areas and staircases to prevent disturbances caused by glare or reflected light. Image Credit: TOM NIVEN

Every space now has the potential to become the site for a selfie, or an urgent group meeting on a virtual platform. The darkening of our interiors as a whole is a subtly unconscious balance recognising that our working day is primarily occupied with a virtually lit interior emanating from our devices. Our dark spaces encourage and remind us to look away from our screens and engage with the people actually present in the room.

Our last example of this consciously uses darkness to separate the occupant from their daylit environment on arrival. An intentionally all-black interior surrounds a warm, lit animated centre, encouraging the need to slow down and disengage from peripheral distractions, concentrating instead on the immediate reality and present company.

We are not predicting that all interiors will become darker with a warm ambience in the next few years. What we do think is already evident: that the entire natural lighting cycle of light and dark, and the ability to choose the different moods these stimulate, will be present in all workplaces. As the distinction between workplace and leisure has already merged, so the capability of lighting diverse psychological modes will be required in every space we occupy, regardless of activity.