Comfortable lighting for work and leisure

I rarely encountered spaces with thoughtful artificial lighting, often the lamps shine in the eyes, the room is not lit enough and the colors of objects look dim or distorted. In addition, lighting often gives scary shadows on faces. I tried to figure out the reasons and make pleasant lighting.

This note describes the general principles for creating comfortable lighting and the actual implementation of budget lighting in a residential workshop.

It began with the fact that I decided to turn a cluttered attic above the garage in Malakhovka, near Moscow, into a residential workshop, in order to solder, drill and create there.
To implement lighting, it was necessary to master some fundamental characteristics:


Illumination, roughly speaking, the amount of light falling on a unit area, is measured in Lux. During the day, street lighting is usually between 2,000 and 100,000 lux. The European Standard for Workplace Lighting recommends the following light values:

300 luxdaily office work that does not require looking at small details
500 luxreading, writing and working at a computer
500 luxmeeting room lighting
750 luxtechnical drawing

According to my observations, a lot of rooms in Russia suffer from insufficient lighting, but in certain places there is also  overexposure . There is evidence that an improper level of illumination can cause headaches, fatigue, visual impairment and other troubles . (more on Wikipedia: Light ergonomics , Light effects on circadian rhythm )

To understand how many lamps you need to create a certain level of illumination, you can use various methods of approximate calculation .

How to measure the illumination in your room?
Typically, illumination is measured at the level of a work surface, such as a table. For simplicity, I measured at 1 m above the floor.
To measure the illumination, I used a light meter, instead of it, you can approximately measure the illumination with a camera with a light meter. When measuring with a light meter, we get EV and then convert to lux using the table .

Color Rendering Index (CRI)

The light sources are such an important feature as CRI (Color rendering index, CRI), the higher the value the better the color rendering, the maximum value of Ra = 100.
In this picture noticeably suffering a color rendering of red and blue colors in fluorescent lamps with low CRI:

In the name of the fluorescent lamps usually contains 3 digits, the first digit characterizes the color rendering index 1 × 10 Ra.
The second and third - indicate the color temperature of the lamp. For example, the most common 640 lamps are lamps with poor color rendering of 6 * 10 = 60 Ra and a color temperature of 40 * 100 = 4000K. Low Ra lamps are not suitable for living spaces , although they have higher light output.

Colour temperature

Color temperature is, roughly speaking, the ratio of red and blue waves in the emission spectrum.

Light up to 5000 K is called warm, and above - cold.
Among friends there are quite a few who prefer warm lighting. It seems to me because of the habit of incandescent lamps (2200-3000 K) and the low color rendering of most fluorescent lamps. Natural daylight, on average, has a color temperature of 6500 K.

There is also such a moment: a person's color perception varies greatly depending on the light. In low light we see blue better and worse red. Therefore, for each level of illumination, there is the most suitable range of color temperature of light sources.
The curve representing this relationship is named after the Dutch physicistArie Andries Kruithof . Here it is:

Simply put, this means that dimmed light (20-50 lux) is best done warm (2000-3000K), and bright light (300-600 lux) - cooler (4000-6000 K) .

What kind of light is needed for productive work?

The topic is extensive, worthy of a separate article.
The results of some studies indicate that cold light improves concentration, reduces drowsiness, etc. Apparently, the fact is that short waves (blue, ultra-violet light) cause suppression of melatonin - a hormone that regulates circadian rhythms and thus activate the body. In addition, there is evidence that bright, cold light helps to cope with the Winter Depression Seasonal affective disorder (SAD) . But at the same time, a lack of melatonin can lead to sleep disturbance and other problems, so that bright cold lighting at night will be more harmful.
In summary, moderate exposure to cold, bright light during daylight hours can reduce drowsiness and improve attention.

Subjective considerations

During the day, the color temperature of sunlight changes:

The illumination and direction of light also change. That is why it seems logical to do intense overhead lighting during the day and muted warm for the evening.
In the end, I decided to make 2 lighting modes : daylight , with a color temperature of 4000K and illumination of ~ 300 lux and  evening low of 2700K ~ 50 lux.

Lamp selection and installation

Because LED lamps are still too expensive, I settled on fluorescent lamps. They are compact or in tubes. For me, tubes have a number of advantages:
  • Ballast Separated from Lamp
  • the tube has a significantly larger glass area with a luminous flux comparable to a compact lamp, due to which the light from it is softer and gives less glare

I chose the T8 Osram L 58W / 940 lamp (cost 240 p. ), They have good color rendering (Ra = 90) and a color temperature of 4000K.
Find for them inexpensive lamps with good electronic ballasts failed. So I bought G13 cartridges (cost 9 p. ) And switched the lamps on my own. The first installation option is presented in the title picture of the post, but it turned out to be unsuccessful. Later, I fixed the lamps using special plastic clips (cost 6 p. ).

Osram QT-FIT8 2 × 58-70 Quicktronic (cost ~ 600 r. ) Is used as a ballast for supplying two lamps . The manufacturer recommends making the cables going from the electronic ballast to the lamp as short as possible, namely:

With a lamp length of 1.5 m, it was not easy to follow all the recommendations. The final connection option:
Connecting fluorescent lamps to electronic ballasts

General view:

The final measurement of illumination: 6.8 EV, i.e. approximately 300 lux.

For evening lower lighting, a spherical lamp is used, which has become unnecessary after repairs in the apartment.

Related Links
Great article on lamp types and their spectrum
Inside view: LED
Health effects of fluorescent
Daylight source D
Sizes of fluorescent

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