HID work usually in the 6,000 to 8,000 range and can have absurd power consumptions going up to 250W these bulbs can produce between 35 to 75 lumens/watt These need special adaptors to create the discharge in the bulb that is not required in any other type of bulb. The downside of HID is their fragility and cost. Xenon lights, also known as high-intensity discharge (HID) lights, work differently to halogen and produce a much colder light (blue range) than halogen. These are especially effective in fog as they have a “penetrating” effect making the light reach further away and to reflect more effectively on objects. In certain countries these bulbs are available in a bright yellow colour which is a mixture of 6,000 and 2,000 K producing a yellow tone light.

They emit usually between 600 to 800 lumen, K light very close to human eye comfort zone although there are some with a blue coating inside the outer glass that changes the K level to the 6,000. These are fairly cheap, power range up to 60W most of commercially available models will be combined 50/55 or 55/60. Note that this refers to K level in the eye comfort zone 3,500 to 5,500 K. Keep in mind that this article refers to healthy people without any type of eyes problems other than the need of glasses for myopia or astigmatism.įrom the table above, you can conclude that intensity of light shouldn’t reach levels over 2200 lux and this should be for a short period of time while levels in the region of 500 to 1000 lux would feel more comfortable and can be sustained for a longer period. People with lighter eyes, blue to light brown, will best adapted to night or darker places than those with dark eyes. This means that should we have too much or not enough light this will result in a state of tiredness to be reach quicker than if we have an ideal amount of illumination.Īll these effects are variable depending on each individual circumstance, level of fitness and even the colour of the eyes. When someone is subject to frequent change of intensity of light or when there is a long exposure to very intense light there is a phenomenon that happens in the brain that results in the person feeling tired, the same (but on a longer period of time) happens when the light is not strong enough and we have to make “an effort” to perceive our surroundings. This means that regardless of the amount of light you are exposed to (within limits) the retina will receive the correct intensity. Miosis also occurs when the light varies in colour (or temperature K). When light intensifies then the Miosis comes to effect to neutralise the amount of light going into the retina. The brown, orange and warmer coloured objects around us change the K colour to warmer light.īecause of this human eye has adapted to operate better in that range. The reason why noon light is “less blue” comparing to noon onwards is because of reflection on objects around us. Human eye is more perceptive to light with a lower K value than on the high side being the range between 3,500 and 5,500 the most “visible” to us. It is well known the effect light have on eyes so no need to go about it.

Hid vs halogen bulb