When it comes to external work environments, orange is the most commonly used colour for hi-vis clothing (followed by yellow).

Why? There are two big reasons:

1. Orange offers the best visibility against almost any background – especially natural greens or industrial greys and whites. While yellow is also very effective, it doesn’t work that well in the indoor environment and against white and grey walls.

2. Orange is the closest to red and red means “stop”, “danger” and “caution” in context of safety and warnings. Humans inherently perceive red as a sign of danger.

The reasons for this are both cultural and possibly evolutionary. But why not red then? Red is also effective, but the prevalence of colour-blindness makes red impractical as it is indistinguishable from green to those people affected by this common condition.

These two reasons explain some of the reasons why hi vis standards require for all hi vis clothing to be orange and/or yellow. However, colour is not the only thing that makes hi vis clothing work. Let’s find out more.

How Do Hi Vis Vests And Jackets Work?

Hi vis vests and jackets utilize the fluorescent and reflective properties of different fabrics so that the wearer is more prominent against their surrounding while performing their job.

In other words, hi visibility clothing achieves its goal through conspicuity. In order to be conspicuous, every hi vis item needs to be easily detected and recognized.

To make the hi vis clothing easily detected, it is necessary to choose the right colors and to ensure contrast against the background.

Contrast is achieved by fluorescent and reflective fabrics on hi-visibility clothing. Therefore, there are two types of hi-vis clothing, based on the way in which they achieve increased visibility:

1. Fluorescent hi-vis clothing is not fluorescent on its own, but it is dyed to achieve that effect. The hi visibility effect is achieved by the special dye “soaking in” the light of a certain wavelength and emitting it. Obviously, for this to happen, there has to be enough light, so this type of hi vis clothing will not do much good when the sun is down. Also, the UV lights do not have the appropriate wavelength, so the fluorescent hi vis clothing isn’t working well in those conditions, either.

2. Reflective hi visibility clothing usually includes a hi vis vest or overalls that have reflective tapes on it. There is no hi vis clothing that is entirely made out of reflective fabric. This type of clothing reflects the light that is pointed directly to it. That is when it is the most useful and that is why the reflective tape is used on hi vis vests for traffic workers and those workers that work at night. The headlights of a car will throw the light ahead of the vehicle and if there is a person in front of the vehicle, the driver will see them due to the reflective hi vis tape for clothing.

Contrast is very important to achieve high visibility. Fluorescent and reflective materials will help to achieve it, but the choice of colors also plays an important role. To ensure better detection, it is necessary to use colors that are the most easily seen.

However, besides improved detection, colors are also essential to ensuring better recognition.