Brightness is also dependent on what is being illuminated. Lighting a tree with dark-colored bark requires a much brighter light than lighting a light-colored object. The most saturated of the filters (such as red, green, and indigo) should only be used on light-colored objects.

Far-UV region

The color shift can be minimized through use of an additional diffusion filter placed on top of the dichroic filter. We suggest trying the VOLT®’s Wide Spread Flood Filters (with Micro Lens Technology). Note that the use of this filter will reduce lumen output to a certain extent.

Ultraviolet radiation also has positive effects on the human body, however. It stimulates the production of vitamin D in the skin and can be used as a therapeutic agent for such diseases as psoriasis. Because of its bactericidal capabilities at wavelengths of 260–280 nm, ultraviolet radiation is useful as both a research tool and a sterilizing technique. Fluorescent lamps exploit the ability of ultraviolet radiation to interact with materials known as phosphors that emit visible light; compared with incandescent lamps, fluorescent lamps are a more energy-efficient form of artificial lighting.

uvlight是什么

Ultraviolet radiation is produced by high-temperature surfaces, such as the Sun’s, in a continuous spectrum and by atomic excitation in a gaseous discharge tube as a discrete spectrum of wavelengths.

No, ultraviolet radiation is undetectable by the human eye. Many insects, however, are able to see ultraviolet radiation.

uvlight中文

Ultraviolet radiation is useful as both a research tool and a sterilizing technique. It can also be used in fluorescent lamps, which are a more energy-efficient form of artificial lighting compared with incandescent lamps.

The other way to change colors is to use tinted glass filters – these are less costly than dichroic filters but they absorb more light (are less efficient) and tend to fade with time.

Near UVand farUVrange

ultraviolet radiation, that portion of the electromagnetic spectrum extending from the violet, or short-wavelength, end of the visible light range to the X-ray region. Ultraviolet (UV) radiation is undetectable by the human eye, although, when it falls on certain materials, it may cause them to fluoresce—i.e., emit electromagnetic radiation of lower energy, such as visible light. Many insects, however, are able to see ultraviolet radiation.

UV light

Wider angle optics exhibit more color shift than do narrower optics since incident angles exiting the filter are wider. Having said this, the color shift (at the beam edges) in most cases is acceptable and may even be desirable since these saturated filters are mostly used to achieve dramatic effects.

The three basic skin cancers, basal- and squamous-cell carcinoma and melanoma, have been linked to long-term exposure to ultraviolet radiation and probably result from changes generated in the DNA of skin cells by ultraviolet rays.

Near UVregion

For example, white light contains all colors in the visible light spectrum. If you pass that light through a blue dichroic filter, only the blue portion of the white light passes through while all the other colors are reflected back towards the light source.

This is an important question. Every color filter (regardless of type) reduces the quantity of light that passes through. There is no way to transform the entirety of a beam of white light into a beam of (for example) green light. A green dichroic filter works by reflecting (back into the fixture) all the non-green wavelengths of light and only allowing the green portion to pass through. If the initial proportion of green light was only 5% of the white spectrum then the resulting quantity of green light will only be 5% of the original. This is why the purer (saturated) the color, the greater reduction in perceived brightness. The resulting illumination will be beautiful, but may be less bright than anticipated and require a light source with higher lumen output.

VacuumUVregion

Ultraviolet radiation is produced by high-temperature surfaces, such as the Sun, in a continuous spectrum and by atomic excitation in a gaseous discharge tube as a discrete spectrum of wavelengths. Most of the ultraviolet radiation in sunlight is absorbed by oxygen in Earth’s atmosphere, which forms the ozone layer of the lower stratosphere. Of the ultraviolet that does reach Earth’s surface, almost 99 percent is UVA radiation.

ultraviolet中文

Ultraviolet radiation is the portion of the electromagnetic spectrum extending from the violet, or short-wavelength, end of the visible light range to the X-ray region.

If the colors are used for architectural features, then the color shift at the edges may not be acceptable. Always test filters if you are unsure about the effects!

Ultraviolet radiation lies between wavelengths of about 400 nanometres (1 nanometre [nm] is 10−9 metre) on the visible-light side and about 10 nm on the X-ray side, though some authorities extend the short-wavelength limit to 4 nm. In physics, ultraviolet radiation is traditionally divided into four regions: near (400–300 nm), middle (300–200 nm), far (200–100 nm), and extreme (below 100 nm). Based on the interaction of wavelengths of ultraviolet radiation with biological materials, three divisions have been designated: UVA (400–315 nm), also called black light; UVB (315–280 nm), responsible for the radiation’s best-known effects on organisms; and UVC (280–100 nm), which does not reach Earth’s surface.

Unlike X-rays, ultraviolet radiation has a low power of penetration; hence, its direct effects on the human body are limited to the surface skin. The direct effects include reddening of the skin (sunburn), pigmentation development (suntan), aging, and carcinogenic changes. Ultraviolet sunburns can be mild, causing only redness and tenderness, or they can be so severe as to produce blisters, swelling, seepage of fluid, and sloughing of the outer skin. The blood capillaries (minute vessels) in the skin dilate with aggregations of red and white blood cells to produce the red coloration. Tanning is a natural body defense relying on melanin to help protect the skin from further injury. Melanin is a chemical pigment in the skin that absorbs ultraviolet radiation and limits its penetration into tissues. A suntan occurs when melanin pigments in cells in the deeper tissue portion of the skin are activated by ultraviolet radiation, and the cells migrate to the surface of the skin. When these cells die, the pigmentation disappears. Persons of light complexion have less melanin pigment and so experience the harmful effects of ultraviolet radiation to a greater degree. The application of sunscreen to the skin can help to block absorption of ultraviolet radiation in such persons.

Constant exposure to the Sun’s ultraviolet radiation induces most of the skin changes commonly associated with aging, such as wrinkling, thickening, and changes in pigmentation. There is also a much higher frequency of skin cancer, particularly in persons with fair skin. The three basic skin cancers, basal- and squamous-cell carcinoma and melanoma, have been linked to long-term exposure to ultraviolet radiation and probably result from changes generated in the DNA of skin cells by ultraviolet rays.

Dichroic filters are circles of glass with a set of coatings that reflect certain colors (of light) and allow other colors to pass through.

When the ozone layer becomes thin, however, more UVB radiation reaches Earth’s surface and may have hazardous effects on organisms. For example, studies have shown that UVB radiation penetrates the ocean’s surface and may be lethal to marine plankton to a depth of 30 metres (about 100 feet) in clear water. In addition, marine scientists have suggested that a rise in UVB levels in the Southern Ocean between 1970 and 2003 was strongly linked to a simultaneous decline in fish, krill, and other marine life.

Some of the more saturated color dichroics show color shifts at the edge of the beam – all dichroics have this issue because the incident angle of the light source(s) determines the projected color.

It is highly recommended that designers test color filters on specific applications before they commit to purchasing the filters for a project – and to use fixtures with high lumen outputs.