Knife

This most likely stems from the fact that it is just not a safe thing to do. In the 2000s, neon lighting is increasingly yielding to digital vehicle lighting, in which bright LEDs are placed on the car and operated by a computer which can be customized and programmed to display a range of changing patterns and colors, a technology borrowed from Christmas lights. This is especially true in more rural areas where carrying a pocket knife is as common as carrying a set of keys. In the 1990s, a popular trend was to customize vehicles with neon lighting, especially underneath the body of a car. In many places in the United States it is considered bad luck to hand an open, folding blade knife to someone. In the late 1960s and early 1970s, manufacturers would sometimes backlight their logos and or other translucent panelling. The puukko is always presented handle first as a sign of trust and friendly intentions. In addition to lighting for useful purposes, automobiles increasingly feature ornamental lighting.

This is especially true in Finland where various non-governmental organizations, clubs and even government agencies traditionally give a puukko (a Finnish fixed-blade hunting/outdoor knife) as a gift to trusted employers or contacts. In the image to the right, the top (white portion) of the tail light is the back-up lamp, which when lit, is used to indicate that the vehicle's transmission has been placed in the reverse gear, warning anyone behind the vehicle that it is moving backwards, or about to do so. In some cultures giving a knife as a gift is considered a sign of respect and trust. Tail lights are always red and are placed in the rear to quickly alert other drivers about the vehicle's direction of travel. Stirring liquids or powders with a knife is considered unlucky; as the rhyme says, "Stir with a knife, stir up strife". Headlights are white or yellow lights placed in the front of the vehicle, designed to illuminate the upcoming road and to make the vehicle more visible. It is common to include a penny, often taped to the blade, with a knife given as a gift which the receiver is to return as "payment". Vehicles typically include headlights and tail lights.

To avoid such ill luck, the receiver should give a coin in return so as to "pay" for the gift. In the last few years, software has been developed to merge lighting and video by enabling lighting designers to stream video content to their LED fixtures, creating low resolution video walls. In some countries it is traditionally believed that the giving of a knife as a gift to a friend will cut or sever the relationship. LED technology is useful for lighting designers because of its low power consumption, low heat generation, instantaneous on/off control, continuity of colour throughout the life of the diode and relatively low cost of manufacture. Knives can be sometimes be customised to the user and/or application:. Patent disputes of RGB colour mixing ideas are currently slowing development, despite the fact many products are being released that take advantage of red, green, blue, and sometimes white, LEDs to mix colours. Folding knives with locking blades are not considered pen knives and are currently a legal "grey area". LED Technology for theatrical and concert applcations is still in its infancy, but is advancing at an incredible rate.

A special exception exists for penknives (pocket knives) which are legal without reason for possession. White LEDs are about the same efficiency as other fluorescents, while red ones can be up to 90% efficient. Sikhs). They are also being increasingly used as Christmas lights. sgian dubh), or if it is carried for religious reasons (e.g. Colored LEDs can also be used for accent lighting, even in fake ice cubes for drinks at parties. chefs) or if it is part of a national costume (e.g. It appears that for now these will be most useful and cost-effective in smaller applications, starting with nightlights.

It is however legal to carry a knife if there is a bona fide reason to do so (e.g. These have come about only since the white LEDs they use, and in turn the blue LEDs which they were based on. In general, knives carried in public places are legally considered to be offensive weapons and the carrier can be charged with "possession of an offensive weapon". They do however last an extremely long time, up to 100,000 hours (compared to around 10,000 for fluorescent and 1,000 for incandescent). In private almost any kind of knife may be owned with the exception of automatic knives (flick knives, balisongs, switchblades) which are under any circumstances illegal. LEDs are a very recent introduction to the market, and they are still extremely expensive for any decent-sized bulb. Knife possession is only legislated in public places. HID bulbs are over 60% and up to 80% efficient.

include court buildings and federal property (the latter of which technically has a limit of 2.5 inch blades). Like fluorescents, all HID bulbs require a ballast, but they also require a few minutes (or seconds for headlights) to warm up after "igniting". Other restricted areas in the U.S. Modern ones are metal halide, used in everything from headlights to floodlights, and with a more pleasant color balance. In some metro areas such as Washington, D.C., going into office buildings or museums, or simply loitering, carrying even small 3" folding knives can be problematic. High-intensity discharge lighting first came about with the mercury-vapor streetlights, and later the high-pressure sodium ones with their characteristic orange color. Cities have ordinances further restricting these laws; in San Antonio, TX, it is a violation to carry a folding knife having a locking blade. Because the above terms are entirely relative and almost arbitrary, color temperature and/or the color rendering index (CRI) are used as absolute scales of color for fluorescents, and sometimes for other types of lighting.

In some other States, fixed-blade knives are banned, open carry is banned, and sometimes concealed carry of anything except pocket knives is banned. Compact ones are usually considered warm white, though many have a yellowish cast like an incandescent. In Texas, for example, individuals may carry knives openly or concealed so long as they are single-edged, and are not daggers, switchblades, or gravity knives (balisong legality is questionable — there have been convictions). There is also a very cold daylight white (DW) which is rather unpleasant to most people and therefore rarely used. Knife laws vary tremendously. In between there is an "enhanced white" (EW), which is more neutral. The knife laws of different countries vary, but are generally strict in Western countries. Fluorescents most often come in cool white (CW), with some home bulbs being a warm white (WW), which has a pinkish tint.

Even small knives are forbidden on all commercial airliners and are among the illegal imports that may be confiscated at airports by customs staff even if packed in luggage. All last far longer than incandescents, but do have some starting trouble in very cold weather when installed outside. Even multitools like the SwissTool, Gerber multitools, and Leatherman multitools are often frowned upon, due to their having relatively large blades and/or locking ability. The compacts can plug into their own fixture, or fit in to a standard screw base for self-ballasted ones. Most Western European nations are very unfriendly toward all knives other than small pocket knives and similarly small tools, which are nonetheless not allowed on planes or in certain other venues. Fluorescents were limited to linear and a few circular ones until the 1980s, when the compact fluorescent was invented. One exception is Austria, where civilian possession of automatic knives including double-edged automatic OTF ("out The front") daggers is allowed. Fluorescent bulbs are about 40% efficient, meaning that for the same amount of light they use 1/4 the power and produce 1/6 the heat of a regular incandescent.

Balisongs (butterfly knives) are only slightly less stigmatized, and tend to be treated as switchblades by law enforcement agencies due to their connection with gang activity. People sometimes find them psychologically pleasing over other types of bulbs due to the more natural colour, which lights some skin tones and other artifacts more accurately. Automatic knives (switchblades) are almost universally banned from civilian carry if not possession. Good halogen bulbs produce a sunshine-like white light, while regular incandescents produce a light between sunlight and candlelight. chef's knives). Halogen capsules can be put inside regular bulbs or dichroic reflectors, either for looks or for safety. Exceptions may be made for hunting knives, and for knives used for work-related purposes (e.g. The risk of burns or fire is also greater than other bulbs, leading to their prohibition in some places.

Carrying knives in public is forbidden by law in many countries. This means that glass bulbs can explode if broken or brought into contact with cool materials such as water, or if operated with residue such as fingerprints on them. (These thoughts were stimulated by an article posted on rec.woodworking.). As well as being much smaller and having a hotter filament temperature, this causes halogen bulbs to have a very hot surface. It has the same relative shape for any depth of cut. The bulb capsule is under high pressure instead of a vacuum or low-pressure noble gas. A wedge shape has the property called "scale invariance". Light energy output is about 15% of energy input, instead of 10%, allowing them to produce about 50% more light from the same amount of electrical power.

On the other hand, if the type of use cannot be predicted, it may be better to sharpen it to a wedge and let the first use bend the edge to an appropriate curve. Halogen bulbs are an improved incandescent. Perhaps this sheds light on the function of razor straps and on the practice of using two angle guides to sharpen a knife. Due to their heat output, incandescent bulbs can cause burns or start fires if used improperly. This contrasts to the usual practice of trying to sharpen knives to a wedge near the edge. This excess heat is then dumped into the air which, in warm climates, must then be cooled by ventilation or air conditioning, resulting in more energy wastage. This is a (microscopic) parabola. About 90% of the energy input is wasted as heat.

So, in this case, the ideal cross section is proportional to the square root of the distance from the edge. The incandescent light bulb was the first type of bulb, and is inefficient at converting electricity to light. (That explains the strength per weight of aluminum, compared to steel.) If the force is applied at the edge, the bending torque is proportional to the distance from the edge. Cost of replacement lamps is also an important factor in any design. Both the area taking the force and the lever arm converting force to torque are proportional to thickness, so the bending resistance is proportional to the square of the thickness. Common characteristics used to evaluate lamp quality include efficiency measured in lumens per watt, typical lamp life measured in hours, and Color Rendering Index on a scale of 0 to 100. Sheets of material are bent by stretching the outside or compressing the inside. Commonly referred to as 'light bulbs', lamps are the removable/replaceable portion of a luminaire which convert electrical energy to both visible and non-visible electromagnetic energy.

Assume the knife is thin and the force is applied at the very edge. These are used for holding acrylic color 'gel', which is available in many hundreds of shades and hues. Making some simplifying assumptions about the forces and the knife edge's ability to resist them may shed some light on ideal sharpening. All Theatrical Lighting Fixtures should have a steel or metal color or 'gel' frame, which slots into a receiver at the front of the fixture. In this case the knife should resist bending or breaking. Floods usually have a halogen tube bulb, backed by a curved symmetric or asymmetric reflector, to give a flat beam to be used for lighting sets or backdrops from above or below. If a knife is used as a scraper or encounters hard particles in softer materials or is used asymmetrically, there may be a sideways load near the tip. PAR lamps contain a reflector (Parabolic Aluminumized Reflector), filament and lens in an enclosed glass envelope, and have various beam types:.

Realigning the edge goes a long way in keeping the knife sharp, as often times, a rolled edge will make an otherwise sharp knife dull. They basically consist of a tube of steel or aluminum with a rounded removable end, for changing lamps (bulbs). This fine process can effect alignment of the edge. PARs or PAR cans are among the most simple and widely-used theatrical lighting fixtures. Other times the final step is done with a steel. PCs produce a more focused beam than fresnels, and are suitable for many of the same applications as fresnels and profiles. It is useful when a knife is still sharp, but has lost that 'scary sharp' edge from use. The body of PCs is longer than fresnels.

It will not cut the edge significantly, but produces a very sharp edge with very little metal loss. Prism Convex fixtures or 'PCs', are much the same as fresnels, but with a prism convex lens instead of fresnel lens. This is traditionally done with a leather strap impregnated with abrasive compounds, but can be done on paper, cardstock, or even cloth in a pinch. Large metal 'barndoors' (four in total) are affixed to the front of the lamp on a rotating ring, to cut away unwanted parts of the beam. Stropping a knife is sometimes a finishing step. The beam size is adjusted by a screw, which actually moves the bulb of the fixture forwards and backwards within the body of the lamp. Rather expensive are sharpening blocks made with corundum. These have a pebbled lens with concentric rings, which results in a large hazy circle around the focal point of the lantern.

Coated hones, which have an abrasive, sometimes diamonds, on a base of plastic or metal are another kind of hone. Used for colour washes, side, front and back-lighting. There are better ways than oil to clean a hone. Profiles have one or two convex or plano-convex lenses, which can be adjusted to create a larger or smaller beam, with a hard or soft edge, and have steel shutters placed at the focal point of these lenses, to cut away unwanted portions of the beam. This is generally bad to do during polishing. Used for front (face) lighting and, with the insertion of a 'gobo' (stainless steel pattern) are used for break-up effects or projecting simple images onto the stage floor or set/backdrop. Oil is sometimes used to lift the metal dust, called swarf, off the stone. Although these fixtures are of the 'fixed' variety, they are adjustable to a huge degree.

Oil is not to be used on these. Types of fixtures include:. Generally, these are more costly than oilstones. Connectors are fuseless, as the fuse for the fixture is provided at the dimmer end of the circuit. They are stored in water, and develop a layer of slurry which dulls the edge if you hone the blade as if honing into the stone. A short cable is normally hardwired or connected to the body of the light and has an electrical connector on the end. Water stones (both artificial and natural) come in very fine grits. Power for the fixtures is provided by dimmers which receive control signal, either digitally multiplexed (DMX) or analog + / − 12v from the main lighting desk or console, where all of the lights used in a production are controlled.

Ceramic hones are also common, especially for fine grit size. Conventional Fixtures are stationary or 'fixed' and normally controlled by a power cable, allowing the fixture to output a beam of light with a brightness of 0 to 100 percent. India is another traditional source for stones. Generally, standard sound XLR cabling is not suitable for lighting, because the gauge of the wire is too small. Arkansas is a traditional source for honing stones, which are traditionally (though a poor practice) used with water or honing oil. The protocol runs on standard three pin XLR cable, although, some older theatres still use five pin DMX cabling. Honing stones (also called whetstones) come with coarse and fine grits and can be hard or soft describing whether the grit comes free. In the United States, automated lighting fixtures are normally controlled by the United States Institute of Theatre Technology Digital Multiplex - 512 Channel Standard Protocol, or simply DMX-512.

If you feel a little bit of pull at the edge or the nail is sightly abraded, you may have a wire burr. Automated lighting fixtures use digital electronics to adjust the color, position, beam angle, brightness, and other special effects. It should come off with no resistance. Conventional lighting consists of stationary lights that can only be moved manually, by means of adjusting, or focusing the fixture with a yoke. To feel for a wire edge, move your thumb lightly across the edge. Concert and theatre lighting use special types of fixtures. This will flip the burr back and forth as it is ground off. It is usually a floor lamp but may be wall-mounted like a sconce.

An alternate method of removing a wire edge is stroking from side to side on a very fine stone, using light strokes. A torchiere (tour-she-AIR or tour-SHARE) is an uplight usually intended for general lighting. If not removed, it will break off in use, and the knife will instantly become dull. A sconce is a wall-mounted fixture, particularly one that shines up and sometimes down as well. Use a slighly steeper angle with very light pressure to do so. Nearly any material can be used, so long as it can tolerate the heat and is in keeping with safety codes. Remove a wire edge (burr) if one forms during sharpening. Some are very plain and functional, while some are pieces of art in themselves.

When you pull a knife up the V, the angle is held for you, as long as you hold the blade perpendicular to the base. Lighting fixtures come in a wide variety of styles for various functions. Another variant is the crock stick setup, where two sticks are put into a plastic or wooden base to form a V shape. Underwater accent lighting is also used for koi ponds and the like. The stone is mounted on a rod and is pulled through these holes, so that the angle remains consistent. This would probably fall under accent lighting, though in a dark nightclub it could be considered general lighting. Examples of sharpening tools are the clamp-style systems, which use a clamp with several holes with pre-defined angles. Other forms include neon, which is not usually intended to illuminate anything else, but to actually be the artwork in itself.

The composition of the stone affects the sharpness of the blade (finer grain produces sharper blades), as does the composition of the blade (some metals take/keep an edge better than others). This uses diffuser panels hung like a suspended ceiling below fluorescent lights, and is considered general lighting. In general, the harder the material to be cut the higher the angle of the edge. The illuminated ceiling was once popular in the 1960s and 1970s but fell out of favor after the 1980s. For an extremely durable edge (such as a chisel or drawknife), sharpen to 30 degrees. Magnifier lamps are also task lighting. Knives that require a tough edge (such as those that chop) sharpen at 20 degrees. The standard lamp and shade that sits on a table is general lighting, while the desk lamp is considered task lighting.

Typical knives sharpen at 15 degrees. The lamp is probably the most common fixture, found in every home and many offices. Very sharp knives sharpen at 10 degrees. A modified version of this is cable lighting, where lights are hung from or clipped to bare metal cables under tension. A guide is very helpful. There are traditional spots and floods, as well as other small hanging fixtures. The smaller the angle between the blade and stone, the sharper the knife will be, but the faster it will dull. A master transformer feeds all of the fixtures on the track or rod with 12 or 24 volts, instead of each having its own.

Knives are sharpened by grinding against a hard surface, typically stone. It has regained some popularity recently in low-voltage tracks, which often look nothing like their predecessors because they do not have the safety issues that line-voltage systems have, and are therefore less bulky and more ornamental in themselves. However, this may also make them brittle. Track lighting, invented by Lightolier, was popular at one point because it was much easier to install then recessed lighting, and individual fixtures are decorative and can be easily aimed at a wall. Most high-quality knives are also tempered very hard, so that they will retain an edge longer. True can lights are uplights, sitting on the floor in a can-like fixture, or mounted on a spike or even in the ground for plants or outdoors. Either use is likely to break off the tip of the blade, or to bend or break the knife beyond repair. Either type can be incandescent, fluorescent, HID or LED, though only incandescents or LEDs make narrow-enough spots.

Most knives are not intended as pry bars or screwdrivers. They may also have their own reflector built-in to the fixture, so that they can take regular and less-expensive bulbs. Steel blades rust easily, but oiling will prevent pitting due to oxidation and tarnish. These downlights use narrow spotlights or "spots", or wider-angle floodlights or "floods", which are both bulbs with their own reflectors. A knife should be kept clean, dry and sharp. Recessed lighting (often called pot lights in Canada and can lights in the U.S.) is popular, with fixtures mounted above the ceiling so as to appear flush with it. Conversely it can be argued that what is dangerous is not knowing how sharp a knife is and thus how much force to use. The effect depends heavily on the exact type of lighting used.

Also, a dull or damaged knife will inflict a worse wound than a relatively 'clean' cut from a sharp knife. Soffit lighting can be general or a decorative wall-wash, sometimes used to bring out texture (like stucco or plaster) on a wall, though this may also show its defects as well. Dull knives lead to excessive use of force to cut materials, increasing the chance that the blade may slip and the force will be transferred to an unintended destination such as the user or another person or object. It is a form of backlighting. A sharp knife is often claimed to be a safer knife. This is often done with fluorescent lighting or rope light, or occasionally with neon lighting. Knives offered to another person should always be offered handle first. Particular forms include alcove lighting, which like most other uplighting is indirect.

When checking the blood circle it is best to hold the knife by the blade, otherwise you defeat the purpose. Backlighting either around or through an object is mainly for accent. In Boy Scout parlance, an area within the radius of the arm and blade length combined is called the "blood circle". Lighting from the side is the less common, as it tends to produce glare near eye level. By extension, assume that the knife is going to slip, and look where the blade would go. Lighting from the front is also quite common, but tends to make the subject look flat as its casts almost no shadows. "Always cut away from yourself" is the basic adage to keep in mind while using a knife. It can also be used for dramatic effect, such as creating interesting shadows by shining through houseplant leaves or across coarse textures like brick or stone.

Chopping knives need blunter angles, out to thirty degrees. Uplighting is less common, often used to bounce indirect light off of the ceiling and back down, though this is less efficient than direct lighting. Slicing knives should have sharper angles, down to ten degrees. This tends to be the most efficient method, used in both offices and homes. 15 to 25 degrees is a good all-around angle. Downlighting is most common, with fixtures on the ceiling casting light downward. The edge is sharpened at different angles for different purposes. Outdoors, general lighting for a parking lot may be as low as 10-20 lux (1-2 footcandles) since pedestrians and motorists already used to the dark will need little light for crossing the area.

A good serration pattern will stay sharp several times as long as a straight edge. Indoors, this would be a basic lamp on a table or floor, or a fixture on the ceiling. The points protect the slicing areas from nicks. General lighting fills in between the two and is intended for general illumination of an area. Serrations on a blade "saw" through the item being cut and stay sharp for a long time. Accent lighting is mainly decorative, intended to highlight pictures, plants, or other elements of interior design or landscaping. For whittling (artistic wood carving) a blade as short as 25mm (1 inch) is common. For example, reading poor-quality reproductions may require task lighting levels up to 1500 lux (150 footcandles), and some inspection tasks or surgical procedures require even higher levels.

Many knives are specific to a particular activity or occupation:. Task lighting is mainly functional and is usually the most concentrated, for purposes such as reading or inspection of materials. Some knives, such as the Scottish dirk and Japanese Tanto function in both roles. Lighting is classified by its intended use as general, localized, or task lighting, depending largely on the distribution of the light produced by the fixture. In general, knives are either working knives (everyday-use blades), or fighting knives. Since the exact orientation of printed material may not be closed controlled, a visual comfort probability can be calculated for a given set of lighting fixtures. Knives exist in several styles:. Proper selection of fixtures is complicated by the requirement to minimize the veiling reflections off of printed material.

Knives can be categorized based on either form or function. Empirically-established depreciation factors are listed in lighting design handbooks. It handles much like the clip-point. Practical lighting design must take into account the gradual decrease in light levels from each lamp owing to lamp aging, lamp burnout, and dirt accumulation on fixture and lamp surfaces. A drop-point blade is very similar to a clip point, but it features the back convexed down, rather than having a clip taken out of it. Hand calculations might only be required at a few points, but computer calculations allow a better estimate of the uniformity and lighting level. An example is a head knife, used in leatherworking both to scrape down leather (reducing thickness), and to make precise, rolling cuts to form shapes. Again the tabulated light levels (in lux or foot-candles) can be presented as contour lines of constant lighting value, overlaid on the project plan drawing.

It is the strongest knife-shape. Where multiple lamps are used to illuminate the same area, each one's contribution is summed. It's good for scraping, and sometimes chopping. Each region is extended to the surface which is to be lit and the area calculated, giving the light power per unit of area. This sort of blade is all edge, with no point, and a handle in the middle. The total lighting power of a lamp is divided into small solid angular regions. An ulu (Inuit woman's knife) knife is a sharpened half-circle. Modelling of outdoor flood lighting usually proceeds directly from photometric data.

The point is actually a second edge on the end of the blade, with a total edge angle of 60-80 degrees. Simplified photometric values are usually given by fixture manufacturers for use in this method. The edge is straight. This method uses the reflectance coefficients of room surfaces to model the contribution to useful illumination at the working level of the room due to light reflected from the walls and the ceiling. The traditional Japanese tanto knife uses the blade geometry of (1). The Zonal Cavity Method is used as a basis for both hand, tabulated, and computer calculations. It is superficially similar to the points on most Japanese long and short swords (katana and wakizashi). More advanced programs can include the effect of light from windows or skylights, allowing further optimization of the operating cost of the lighting installation.

(6) An Americanized tanto style knife is thick towards the point. The computer program will then produce a set of contour charts overlaid on the project floor plan, showing the light level to be expected at the working height. Sheepsfoot knives are good for whittling, including sheep's hooves. Each fixture has its location entered, and the reflectance of walls, ceiling, and floors can be entered. It gives the most control, because the dull back edge is made to be held by fingers. For larger projects or those with irregular floor plans, lighting design software can be used. (5) A sheepsfoot knife has a straight edge, and a curved dull back. Based on the positions and mounting heights of the fixtures, and their photometric characteristics, the proposed lighting layout can be checked for uniformity and quantity of illumination.

The Bowie has a clipped blade. For very simple layouts in common configurations, tables and simple hand calculations can be used. If the false edge is sharpened it increases the knife's effectiveness in piercing. This certification process is the only national examination in the lighting industry and is open not only to designers, but to lighting equipment manufacturers, electric utility employees, etc. The sharp tip makes the blade exceptional as a pick, or for cutting in tight places. Individuals who pass this exam become ‘Lighting Certified’ and may append the abbreviation LC to their name. The back edge of the clip can have a false edge that can be sharpened to make a second edge. The National Council on Qualifications for the Lighting Professions (NCQLP) offers the Lighting Certification Examination which tests rudimentary lighting design principles.

(4) A clip point blade is like a normal blade with the tip "clipped" to make the tip thinner and sharper. Those fully independent designers who meet the requirements for professional membership in the association typically append the abbreviation IALD to their name. This shape is primarily used for fighting knives (daggers, bayonets) because it can cut in both directions and point in line with the handle. The International Association of Lighting Designers (IALD) is an organization which focuses on the advancement of lighting design education and the recognition of independent professional lighting designers. The idea is to make a blade that cuts in either direction, with a strong sharp point. This data is typically expressed in standardized form defined by the IESNA. (3) A double edged or spey blade has two edges. Manufacturers of lighting equipment publish photometric data for their products, which defines the distribution of light released by a specific luminaire.

Such a knife is better for slicing than a normal knife. The Illuminating Engineering Society of North America (IESNA), in conjunction with organizations like ANSI and ASHRAE, publishes guidelines, standards, and handbooks that allow categorization of the illumination needs of different built environments. This lets a lightweight knife have a larger curve on its edge. Lighting design requires the consideration of several design factors:. (2) A curved, trailing-point knife has a back edge that curves upward. These electrical lighting systems should also consider the impacts of, and ideally be integrated with, daylighting systems. Therefore, the knife can chop as well as pick and slice. Therefore, it is important that the sciences of light production and luminaire photometrics are balanced with the artistic application of light as a medium in our built environment.

The curve concentrates force on a small point, making cutting easier. Other buildings, like casinos and theatres, are primarily concerned with enhancing the appearance and emotional impact of architecture through lighting systems. A dull back lets the wielder use fingers to concentrate force; it also makes the knife heavier and stronger for its size. Some buildings, like warehouses and office buildings, are primarily concerned with saving money through the energy efficiency of the lighting system. (1) A normal blade has a curving edge, and flat back. Some buildings, like surgical centers and sports facilities, are primarily concerned with providing the appropriate amount of light for the associated task. There are a variety of knife blade shapes; some of the most common are listed below. Proper comprehensive lighting design requires consideration of the amount of functional light provided, the energy consumed, as well as the aesthetic impact supplied by the lighting system.

Vanadium, and perhaps molybdenum, also increase corrosion resistance. Lighting design as it applies to the built environment, also known as 'architectural lighting design', is both a science and an art. Vanadium and molybdenum are important alloy metals because they make the gain size smaller, which improves hardness and toughness. . These explain its reputation for long wear (the carbides are harder than the metal) and for being harder to sharpen and not taking as good an edge as rustable, low alloy ("carbon") steel (the ceramic particles themselves cannot be sharpened easily.) The bulk hardness and toughness of stainless steel tend to be lower than those of low alloy steel. In major cities, light pollution is of growing concern. Stainless steel usually has particles of chromium (or other alloy metal) carbides. Smaller or rural roads may not be lit.

It is corrosion resistant (though knife steel is less so than higher nickel stainless steel) because, except in acid, one of the metals or one of the oxides is always stable. These are a form of street furniture. Stainless steel is steel with very high (12–18%) chromium content. In cities, streets are often lighted at night, usually by streetlights (also known as lamp-posts). Stainless knife steels are high in carbon, but "carbon steel" means there is not also a lot of chromium. Likewise, lighting can also be an important part of landscaping. Knife steel has fairly low nickel content, because nickel tends to keep steel in the austenitic structure, even when cold. Indoor lighting is a form of furnishing, and a critical part of interior design.

The blade is then tempered by heating to an intermediate temperature for a period to make it less brittle. Modern portable lighting is typically a flashlight (also called a torch) running on batteries. It is formed as it is quenched, changing it from the austenitic structure that it has at high temperature to a hard, but brittle martensitic structure. Modern freestanding lamps typically have a base which holds up a light bulb which is covered by a lampshade. All knife steel is tempered martensite, which means that a fine-grained crystal structure with lattice irregularities that make it hard. Indoor lighting is provided by light sources, today usually electric lights, but previously by gas, candles or oil lamps. Some manufacturers, particularly of kitchen knives, make ceramic blades; these are harder and stay sharp longer, but because of their brittleness, chip and break more readily. "Natural" indoor lighting is light from the sun and the sky coming through the windows.

Forschner/Victorinox make decent, inexpensive kitchen knives; high-end manufacturers include Wüsthof, Global, Henckels and Böker (Tree Brand). Lighting refers to the devices or techniques used for illumination, usually referring to electrical light sources such as lamps or flashlights. There is typically more demand for exotic alloys in the utility, outdoor, and tactical or combat knife categories than there is in the kitchen knife category. Very wide Flood. The cost of the process restricts it to high-end knives. Wide Flood (W or CP62). The original craft of Damascus steel may be lost, but not being a registered trademark, the name is today used to apply to the equally old but less exotic pattern welding, which creates layered and admired patterns. Medium Flood (M).

All three are more ductile than typical stainless steels, but have quite a vocal support group despite concerns about health effects of cobalt content. Narrow Spot (NS or CP61). Other manufacturers sometimes use titanium, cobalt, and cobalt containing alloys. Very Narrow Spot (VNS or CP60). Knife manufacturers such as Spyderco and Benchmade typically use 154CM, VG-10, S30V, and CPM440V (also known as S60V), as well as high-speed high-hardness tool steels like D2 and M2. Flood (used primarily for lighting backdrops). A variety of exotic steels and other materials can be used to form blades. PAR (exchangeable bulbs create varying beam angles/effects).

Steels having high carbon but low chromium content are prone to rust and pitting if not kept dry. Prism Convex (variable beam angle). Chromium is the major alloying element in stainless steels, giving them the 'stainless' quality. Fresnel (variable beam angle). Stainless and semi-stainless steels include D2, S30V, 154CM, ATS-34, and 440C. Profile spot (various beam angles). Tests done by Razor Edge Systems, and described in their book "The Razor Edge Book of Sharpening" indicate that stainless steel knives hold an edge better than regular steels. electrical codes and building codes.

Stainless steels have gained popularity in the latter half of the twentieth century because they are highly resistant to corrosion (so they usually only rust under extreme conditions). operating schedule of the building. Knife blades are usually made of steel; although there are a few knives using materials like high tech ceramic and titanium, these are very uncommon. maintenance capabilities. A hole in the end of the handles allows the knife to be hung or placed on a lanyard. dirt and dust generation/accumulation. For a large knife, it is desirable that the handle is thick enough that one's fingers just meet one's palm when the knife is gripped tightly. surface characteristics (reflectance, specularity).

The handle of a knife should be made of a non-slip material. physical size of the environment. In kitchen knives, it keeps chopped items from moving back toward the hand. aesthetic architectural impact. In piercing, this helps keep the knife from jamming, for example in bone. initial and continued operational costs. See 1 Some knives also have a shoulder in which the blade thickens as it meets the handle. occupants of the environment.

Additionally, a groove on the blade can reduce surface tension between the blade and the item being cut, thereby allowing easier movement or removal of the blade. tasks occurring in the environment. In reality, its only function is to make knives and swords lighter while sacrificing little strength; on most knives it has more decorative worth. According to a popular myth, it lets bleeding occur from an artery without removing the knife. A fuller, sometimes called a blood gutter or blood groove, is a groove on the side, along a blade.

The blade in turn consists of a tip, a spine, an edge and a heel. The bolster functions as a balance point and handguard, to prevent fingers from slipping onto the blade. The tang is an extension of the blade into the handle. A knife consists of a tang, a bolster, a blade and a handle.

. The importance of the knife as a weapon has declined as more specialized weapons have been developed, but the knife remains the universal tool. In the West, multi-purpose pocket knives are commonly carried, to be available anywhere. Today, these are not frequently sharpened, and most sharp knives are used in kitchens.

Together with the fork and spoon, the knife has been a common eating utensil in the Western world since, at least, the Middle Ages. While the materials have changed over time, the basic design remains the same. Later on with advances in smelting and metallurgy the blades were made of bronze, iron, then steel. The first knives were flint or other rock, chipped or ground to an edge, sometimes with a handle.

Knives have been used as tools and weapons since the Stone Age. The blade of a knife is usually pointed and may have one or two cutting edges. A knife usually consists of a blade, commonly less than 12 inches (30cm) in length, attached to a handle. A knife is a sharp-edged hand tool used for cutting.

Everybody's Knife Bible by Don Paul, ISBN 0938263234. The surface finish of the blade can be darkened or polished. The handle can be altered in shape (for better grip) or material (to prevent electric shock or burns).