- Why use a blue porch light? [closed]
- How to Use Lighting to Show You Care
- Flashlight, Spotlight and Headlamp Buyer’s Guide
- What does the colour of a light bulb depend on?
- LEDs and the Psychology of Light and Color
- If You See A Green Light On Someone’s Porch, You Need To Know What It Means.
- Based on the 2014 United States Census Bureau there are 19.3 million veterans in the United States.
Why use a blue porch light? [closed]
Why use blue lights on your porch?
Blue light deter druggies from injecting themselves because they cannot see their veins so easily. Junkies keep away!
Blue lighting is sometimes used in public toilets (restrooms) to make it more difficult for drug users to inject themselves (veins are harder to see).
It was more difficult to see my veins through my skin, but there was normal-coloured lighting in the street outside, and one would assume that the users would thus just go outside instead, though the risk of detection is greater. (An additional result of the blue lighting is that, on going outside after spending more than a few seconds in the toilets, the daytime world appears much brighter and more optimistic, even on an overcast day: could retail designers or others make use of this effect? Do they already?) – A vein attempt?
As Timmy Jim points out in his comment people use blue lights to show support to fallen police in the line of duty.
Some people use them for the Fourth of July holiday:
Burke said his customers began asking for blue lights Wednesday. Since then, he estimates, his Home Depot store has sold between 50 and 60 blue lights. Normally, the store sells one to five a week. Usually, he said, residents want blue lights for parties or the Fourth of July holiday. – Area residents flipping switches to blue porch lights to back police
There is also the Blue Light Safety Project:
This is the Blue Light Safety Project.
A blue light signifies that this house is a temporary safe space, open to anyone that feels in danger or threatened. Knock on the door and the residents will provide support until you feel safer or can make other arrangements. If no one is home, you are welcome to sit on the porch for a short time until you feel safe to continue on your way.
The project is an attempt to provide safety in our community outside of institutional solutions such as police. – Blue Light Safety Project
Or you could be like me. I use a blue light on my porch simply because I do not want a lot of white light coming in through the window!
Written by: Greg Ellifritz
Let me preface this article by saying that my words likely do not reflect the views of the average police officer and most certainly don’t reflect the views of my (or any other) police bosses. These are the thoughts of a single police officer who thinks a bit differently than most of his peers. If you can accept those premises, we will get to the topic at hand…
Today is the beginning of police memorial week. It’s a week designated to honor currently serving and deceased police officers. Residents in many communities are choosing to celebrate police week by replacing their external light bulbs with bulbs that are blue colored instead.
As a cop, I appreciate the support. I also think it’s a dangerous idea. You are broadcasting valuable information whenever you engage in a campaign like this. Some of the people who obtain said information will use it against you.
You are thinking like a law abiding citizen thinks. I need you to stop that and take a moment to think like a criminal instead. What information would the presence of a blue porch light provide?
Think about who may do this blue light thing. It will be cops, their loved ones, and people of a “law and order” political identity. How would a criminal use that info?
– The easiest and most likely use is for burglary. Almost all the houses with blue lights will have guns and money. Very few people who are actually poor will change their light bulbs as blue colored light bulbs cost more than the regular variety. If you have the time and disposable income to celebrate an occasion by purchasing a novelty light bulb, you probably have some valuables in the house. They’ll wait for you to leave and then steal your stuff.
– Some people simply hate cops. Your outdoor property may be damaged or defaced just because the criminals want to hassle “the man.” In the worst case scenario, there is a possibility that our current street gangs will get larger and more organized. Once they figure out that your family member is a cop, you may be a target for violent reprisals or kidnapping. Look at what is going on in both Mexico and Venezuela. Killers are assassinating cops where the cop lives, rather than where he is working.
If you want to kill a cop, it’s a lot harder when he is on duty, armed, wearing body armor, and has instantaneous communication with hundreds of others who also have a bunch of guns and body armor. It’s much easier to kill a cop at his home where he is relaxed and may not even be carrying a pistol.
– Remember the ongoing violent left/right political activism that we’ve been seeing for a couple years? What about the ANTIFA confrontations going on around the country? If you identify with the police, in ANTIFA’s eyes, you are a “fascist.” Do you really want a bunch of masked nut jobs tearing up your stuff or beating your family members because you support your local police officers? I don’t think that is a risk that is worth taking.
Thank you for the sentiments, but please don’t bathe your house in blue lights this week. If you want to support your police force, work to ensure your local government doesn’t put politics before officer safety. Work to ensure that your police department has invested in the process of selecting high quality police officer candidates and then is able to immediately dismiss those who demonstrate they are unsuited for the job. Ensure that all your officers have the best training available and that the department provides them with decent equipment so that they can actually do their jobs.
In this cop’s mind, the suggestions above are far more meaningful than screwing a blue light bulb into the receptacle on your front porch. Don’t put yourself or your family in danger by openly aligning with a group that some folks consider to be the “enemy.” Be smart. The blue porch light is a “gray man” fail. The risks far outweigh the benefits.
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How to Use Lighting to Show You Care
by Lani Furbank
Image Credit: Master Isolated Images “Teamwork With Idea Light Bulbs” on FreeDigitalPhotos.net
In the age of social media activism, sometimes it’s nice to show your support for a cause in a concrete, lasting way, instead of just posting something on Facebook. From buttons and plastic bracelets to rallies and ribbons, there are many iconic symbols that represent various issues. More recently, colorful lighting has become a popular way to display your support after dark. Here are a few campaigns that quite literally shine a light on their causes.
Project Blue Light
Project Blue Light is a nationwide movement to recognize and honor fallen police officers. To participate, you simply display a blue light outside your home or inside a window. This originally started during the holiday season, but many supporters choose to keep a blue light illuminated on their porch or home facade during National Police Week in May, and others opt to shine blue for the entire year.
Light It Up Blue
Blue lights are also a way to display support for autism awareness. In 2007, the United Nations General Assembly designated April 2nd as World Autism Awareness Day. Three years later, the research and educational organization, Autism Speaks, launched the “Light It Up Blue” campaign to raise awareness about autism in honor of World Autism Awareness Day and Autism Awareness Month (April).
Beginning on April 2nd, autism awareness supporters are encouraged to turn their lights blue – either by changing out white light bulbs for blue ones, or covering light fixtures with blue filters, lenses, or gel sheets. Throughout the month, thousands of homes, schools, iconic landmarks, museums, stores, entertainment venues, and bridges will go blue.
Light Up The Sky for Breast Cancer
Light Up The Sky For Breast Cancer is a nationwide event scheduled during the month of October, which is Breast Cancer Awareness Month. The timing of the event is staggered among time zones, so that the event will occur simultaneously across the country. Each year, participants gather together in small groups or in designated central locations, observe a moment of silence, and then, at a specific time, display a sea of pink lights, each one representing a loved one who battled breast cancer.
Lights for the Cure
Over the past 14 years, Philadelphia has turned their skyline pink through Lights for the Cure in support of breast cancer awareness. The vice president of public affairs at CBS 3 in Philly came up with the idea of promoting awareness by illuminating bright pink lights throughout the city during the month of October. Now, in partnership with Susan G. Komen Philadelphia, iconic landmarks such as Lincoln Financial Field, the National Constitution Center, the Bethlehem Steel blast furnaces, the Liacouras Center, and Franklin Square fountains will be tinted pink with almost 100 other buildings in the city.
Purple Light Nights
In October, 2007 the Covington, WA Domestic Violence Task Force held its first Purple Light Nights campaign during Domestic Violence Awareness Month. Since purple is the color that represents domestic violence awareness, the CDVTF came up with the idea to shine purple lights in remembrance of victims who lost their lives and to support the brave survivors of domestic abuse.
Black lights are recommended for Purple Light Nights events, as they emit a true purple hue. A black light bulb can be placed in your front porch light, or even inside in a front window. Another option could be to add purple string lights around the exterior of your home or door. In public areas, it’s recommended to display string lights in prominent places such as business storefront windows, trees, or building and bridge facades. Purples spotlights are a great way to show support on landmarks such as museums or town halls.
Light Up Green
The “Light Up Green” campaign in May is for Lyme Disease Awareness Month. It was started by a Lyme disease patient named Samantha who wanted her friends and neighbors to replace their porch lights with green bulbs to raise awareness for Lyme disease. The campaign has since grown, and now buildings around the world are washed in green light during the month of May to support Lyme patients.
Go Red for Women
The American Heart Association asks supporters to help their city go red for women in support of American Heart Month in February. People are encouraged to use red lights to illuminate the exterior of homes and office buildings, as well as string red holiday lights or rope lighting to accent trees, bushes, landscaping, columns, poles, and other architectural features. The association recommends using gel light covers, switching LED light colors, or purchasing red light bulbs. They even offer equipment to borrow during the month so that everyone can join in.
So, if you’re really passionate about showing your support for an important cause, don’t just wear a bracelet or display a ribbon. Grab people’s attention and spread awareness by shining a bright and colorful light for all to see.
Flashlight, Spotlight and Headlamp Buyer’s Guide
Further confusion arises when you realize that flashlights, spotlights and headlamps are measured in a number of different ways and the output of any light is affected by the quality of the reflector, amount of battery power available, quality of the bezel and the output of the bulb or LED. (I’ll explain these factors in detail.)
While all elements of a portable lighting device are important, none have as much impact on the total picture as the bulb or LED that does the hard work – making light. Tremendous advances have been made in light technology in just the past five years, but the real juggernaut has come in just the past two years in terms of applied technology to products one can use. When you consider the technological advances in portable lighting, it’s a lot like comparing the sound quality of a digitally recorded CD to that of the historic vinyl LP. Today, highly engineered, machine-tooled frames, computer-designed reflectors, space-age bezels and advancement in bulb technology make portable lighting almost as remarkable as Luke Skywalker’s lightsaber.
Originally, incandescent bulbs had a tungsten filament surrounded by a vacuum inside a glass tube. Incandescent literally means to give off light as a result of being heated. The most salient limitation of incandescent bulbs is the output spectrum, which has a long sweeping tail that falls on the red side, extending well into the infrared. With traditional incandescent lamps, the majority of the output actually falls in the infrared and ends up as just heat. In fact, with standard incandescent bulbs only about 10% of the consumed electrical energy is converted into useful light, or light that is in the visible part of the spectrum. If tungsten could be operated a few degrees hotter it would produce much more light. Unfortunately, tungsten is operated as close to the melting point as possible, and even a few more degrees would burn the filament up very quickly.
Longer-life tungsten bulbs achieve their increased lifespan with heavier filaments that will handle more heat, but produce less light.
The next step in the evolution of incandescent bulbs was substituting gases for the vacuum. Argon/nitrogen were the initial gases used, but it was discovered that krypton conducts heat less than argon, and xenon conducts even less heat than krypton. In addition, the larger atoms of krypton and xenon are better for bouncing evaporated tungsten atoms back onto the filament than the smaller atoms of argon and nitrogen. All of the bulbs listed below are technologically superior to the standard tungsten bulb, and with the exception of High Pressure Xenon bulbs, all have tungsten filaments that will last much longer, but eventually burn out and have to be replaced. Filaments are fragile and subject to breaking when jarred severely or dropped, especially when burning. The down side to bulbs is that they have a limited life, more dominant shadows and have a very high rate of power consumption.
Types of bulbs:
Halogen bulbs are made of glass filled with a small amount of halogen gas. When standard filament is charged with current small particles of tungsten evaporates and is collected on the inside of the bulb’s glass surface. When a trace amount of Halogen is added to the bulb, a chemical reaction takes place, which removes the tungsten from the wall of the glass and deposits it back onto the filament, extending the life of the bulb.
In order for that beneficial chemical reaction to take place, the filament needs to be hotter than for standard incandescent bulbs. A hotter filament produces a whiter light and is more efficient – more lumens per watt of consumed power. Halogen bulbs offer energy savings compared to conventional incandescent light bulbs, but fall short of xenon bulbs. The average lifespan of a halogen bulb is 2,500 hours.
- Krypton bulbs are made of glass and filled with krypton gas. This technology uses a filament, but produces double the average life of conventional tungsten light bulbs with an average life up to 2,000 hours.
- Xenon bulbs are made of glass and filled with metal salts and a mixture of noble (non-reactive) gases including xenon, which produce a clear, white light. The average life span of xenon bulbs is 5,000 hours. Xenon bulbs produce low levels of infrared and ultra-violet radiation while emitting twice the amount of light of a halogen bulb. Xenon is very efficient, when compared to halogen, producing twice the light while consuming half the power.
- High Pressure Xenon bulbs are made of thicker glass containing metal salts and a mixture of noble (non-reactive) gases including high-pressure xenon gas pressurized to several atmospheres. HP xenon bulbs are typically about half the size of xenon bulbs and operate on a gas discharge principle. An arc of light is created between two electrodes in a glass tube filled with gas. Xenon gas bulbs emit a clear, white light with an average lifespan of about 5,000 hours. HP xenon bulbs produce low levels of infrared and ultra-violet radiation while producing twice the amount of light of a halogen bulb, and consuming only half the power.
Once Light Emitting Diodes (LEDs) were invented, a lot of changes started happening, almost at the speed of light. LEDs are basically a light bulb without a filament to burn out, and since they are very efficient at creating light without heat loss, they don’t get hot. The LEDs longevity is further enhanced by its construction. An unbreakable, crystal clear, solid resin encases each LED and makes it nearly indestructible. The drawback to LEDs is their limited output for projecting light over a great distance.
All LEDs are environmentally friendly since they have no waste or mercury. All LEDs operate at low temperatures, which make them safe to touch. LEDs have an average lifespan of 100,000 hours of continuous or cumulative use, operate on low voltage DC power, and produce no UV light. Light output of LEDs are measured in lumens; energy input to a lamp is measured in watts. The efficiency of a lamp is expressed as lumens per watt.
Types of LEDs:
- NICHIA 5 mm LEDs produce 2-3 lumens of light for each LED. LEDs provide instant illumination; produce low heat and no UV light. LEDs are also more energy efficient than conventional incandescent light bulbs because most of the energy is turned directly into light; however, single LEDs do not create a significant amount of light. Most sophisticated designs today use clusters of LEDs to increase a unit’s output and LUXEON LEDs accomplish this task very nicely.
- LUXEON 1-Watt LEDs produce up to 25-30 lumens and provide 10 times the lumens of standard NICHIA LEDs.
- LUXEON 3-Watt LEDs have an output of up to 75-80 lumens, or three times the lumens of Luxeon 1 watt LEDs and 25 times the lumens of standard NICHIA LEDs.
- LUXEON 5-Watt LEDs have an output of up to 120 lumens, provide four times the lumens of LUXEON 1 watt LEDs and 50 times the lumens of standard NICHIA LEDs, the equivalent of 50, 5mm LEDs.
High-Intensity Discharge Lamps (HID)
This type of lamp is the best choice for those who want night-slicing brightness combined with long-lasting efficiency.
Both incandescent bulbs and HID lamps can generate high lumen output and long-range brightness. Incandescent bulbs put off light when an electric current is passed through a thin piece of filament, causing it to heat. HID lamps replace filament with gas and metallic or sodium vapor. An electric current (arc) passed between two electrodes heats up the vapor creating an intense, white light. Without the filament, HID lamps are able to generate a higher percentage of pure light as opposed to heat.
The color temperature of HID lamps resembles natural light more closely than the yellow tint of incandescent lighting. Similar to fluorescent lamps, HID lamps use a ballast to start and maintain the electric arc. The ballast is the reason why HID lamps require a few minutes to reach maximum brightness and may flicker when first turned on. Because of the space requirements of the ballast, HID lamps are currently only used in spotlights and some flashlights.
Combine all these technologies together and you can see why HID has advantages over incandescent bulbs in terms of greater lumen output, whiter light, longer service life and less power consumption. To the average camper, hunter and angler this means an HID spotlight or flashlight has the sunlight-replicating brightness to cut through pitch darkness without needing as many replacement lamps or charges.
Types of HID lamps:
- Mercury vapor is the oldest type of high-intensity discharge lamps. It generates a blue/green light that renders colors poorly, however a phosphor coating can alter the color temperature and improve color rendering to some extent. Most manufacturers favor metal halide lamps over mercury vapor for its accurate color rendering and higher efficacy. Mercury vapor and sodium lamps have the longest lifetimes (16,000 – 24,000 hours) of the HID lamp types.
- The main advantage of sodium HID lamps is energy efficiency. Similar to mercury vapor lamps, sodium HID lamps have poor color rendition compared to metal halide lamps but longer lifetimes (16,000-24,000 hours). They produce light with an orange-pink cast. Color-corrected lamps producing a whiter light are now available, but some efficiency is sacrificed for the improved color.
- Cabela’s HID spotlights and flashlights use metal halide lamps because of their many advantages. They offer high efficacy, excellent color rendition, long service life and superior lumen performance. The bright, white light is considered the best of all the HID lamps for accurate color rendition. Adding metal halide gases to mercury gas within the lamp results in greater light output, more lumens per watt, and better color rendition than from mercury gas alone. These lamps do lose some efficiency and have a slightly shorter life span (5,000 – 20,000 hours) as a tradeoff for their superior color rendering.
After considering the bulb/lamp/LED factor, when you break down the issues involved in selecting an illumination device, there are only a few factors that are relevant.
Size can be a factor, especially with the magnum output and size of the Thor 10-million candlepower spotlight.
While it has phenomenal output, putting this unit in a backpack would just about fill it up, not to mention the weight. Choose a light that will be comfortable to carry if you will be traveling on foot. Generally, the power source dictates the design and size as well as weight of an illumination device. While five-D-cell lights are impressive in length, their strong suit is that of impromptu Billy club, when weight, diameter and length are most advantageous.
Brightness is always a factor, especially if you are going to be illuminating objects at great distances or need to see items in great detail.
Battery life is important, not only in terms of sustained brightness but operation time as well. Available and sustainable power is a critical factor if you are going to a remote region where replacement batteries or access to recharging current will be limited or nonexistent. Power is particularly important with some of the newer technologies that require high output power sources such as nickel-cadmium, lithium or lithium-ion batteries.
Construction is a key factor if you tend to drop things or use your light in rain, sleet or snow. The most rugged flashlights are made of machined aluminum with O-rings to keep out moisture. You’ll find that anodized finishes are very hard and difficult to scratch under normal use, which will keep your light looking new for many years.
Once you start sorting out these factors, you’ll quickly find that bulb/lamp/LED choice will play a major role in all of the above. Here are some considerations in terms of output, lifespan and power consumption.
“How bright is that light?” is a question that has been answered in many ways. The problem with scientists and engineers is that they quantify everything in a number of different ways and comparing the two is often baffling to the average layman. Books have been written on the issues involved with the measurement and comparison of light and light sources. These voluminous tomes are peppered with terms like lumen, candela, lux, emittance, light power flux, luminous intensity, incident flux and diffuse reflected flux. Hopefully, these basic descriptions will shed enough light on the subject to help you through the process.
Candlepower is an obsolete unit of illumination, equivalent to one lumen ft2. And here comes the kicker! A candlepower as a unit of measure is not the same as a foot-candle. A candlepower is a measurement of the light at the source, not at the object you light up.
The most common terms used to evaluate a light’s capacity are candlepower and lumens. Lumens are the easiest to understand, and also the most regulated by the International System of Measurements. In scientific jargon, one lumen is the unit of luminous flux equal to the amount of light given out through a solid angle by a source of one candela intensity, radiating equally in all directions. Simply put, a measure of the output of the light source without the aid of a reflector.
The problem with trying to compare candlepower with lumens or any other measurement is that you don’t know how the candlepower rating was determined. Peak beam candlepower is a measurement of the brightest spot in a focused beam, and not the true output of the light source. The most important issue is that regardless of the rating system, the effectiveness of a light source depends upon the perception of the human eye and is therefore subjective and relative to each individuals ability to see the full spectrum of light. Because of this human factor, perhaps the most effective way to compare lights is to turn it on and compare it to another and see what you think for yourself.
Other Factors to Consider
As noted above, the quality of a reflector can have a tremendous impact on both a light’s brightness and the beam it projects. Manufacturers have found that one of the easiest ways to boost a light’s output is to enhance the surface directly behind the bulb. With the advent of computer design and space age materials, reflectors have come a long way. You’ll find a number of types in terms of both design and material. In some instances you may want a spotlight that throws a very narrow beam for a great distance, and at other times you may want a floodlight that illuminates a wide area equally and brightly.
Parabolic reflectors are computer designed to maximize the angle of reflectivity while the surface is coated to magnify existing light and project it to its fullest potential. The result is a beam that appears much brighter when compared to a light with the same lumen output, but without a highly engineered reflector. Photon-tube reflectors deliver an extra-wide and focused beam at the same time.
One shortcoming of traditional flashlights was their highly focused beams and bright only output. When you left the campfire and ventured into the dark woods, the bright beam was narrowly focused and due to its brightness it made the surrounding woods even darker because your eyes couldn’t adjust. LEDs produce a softer light, and when you use a light that spreads the beam even wider, the affect is more like that of a fluorescent light that gently illuminates a wider area.
Reflectors can improve the overall brightness of a light or focus the beam in a very narrow area, but with some lights today, the strategic placement of LEDs in combination with incandescent bulbs gives you the ability to do both.
A bezel is just a fancy word for the transparent material that allows the light to shine through and keeps moisture out. Glass or plastic were the old world options and neither performed well. Glass was easily broken and plastic was easily scratched, became discolored with time or became dislodged with very little pressure. Today’s high-tech models feature rugged materials that are clearer, harder to scratch and nearly impervious to hard impacts. If you’re really abusive to gear, look for bezels made of Lexan or Pyrex.
Another option with both flashlights and headlamps is color filtration. When you are working in the dark and want to preserve your night vision, having the ability to filter the color of light you are using will help you avoid that lag time between viewing something with a light, then trying to see without it. In addition to green, you will find blue, red and infrared filters that greatly reduce the problem of working in the dark. Also, keep in mind that color filters are very useful for finding a deer stand or moving in to set up for any game before dawn, since four-legged animals are basically color blind and unable to see your light.
The main advantage of a headlamp is the convenience of hands-free operation. A headlamp is usually worn on the forehead, but some models offer side-mounted lights. Regardless of the position on the head, with a headlamp, everywhere you look is illuminated. The only disadvantage is to others you may be hunting, camping or working with. When you talk to someone, and look directly at them at the same time, your headlamp will shine into their eyes. It takes a little getting used to, but I haven’t found this to be a big problem when compared to the advantage of having both hands free and lots of directed light.
The same issues affecting brightness and hours of operation for flashlights are relevant to headlamps as well. One factor that is more pertinent to this type of device is weight. When selecting a headlamp, give serious consideration to weight as well as brightness and battery life. The amount of weight you are willing and able to tolerate on your head is a personal decision, most often affected by physical stature. Keep in mind that the weight of a headlamp will be cumulative over the period of time you intend on using it. While it may not be a significant factor if you’re using one to set up camp or gather firewood at night, if you’re hiking, fishing, field dressing a deer or frog gigging for hours on end, weight can be an issue.
These are the choice when nothing less than the brightest, farthest-reaching portable lights will do. Scouting for game in the dark, varmint hunting and emergency situations are all opportunities where a good spotlight will be useful. Advancing technology has trimmed some of the weight and bulk off of these large lights. However, if you are concerned about durability don’t opt for the smallest and the lightest. Take a hard look at materials. Machined aluminum will hold up better against drops than a plastic body. Consider HID lamps if you want the best combination of brightness, service life and low power consumption.
Without an electric source a flashlight, spotlight or headlamp is only ballast in a backpack or pants pocket. To make sure you have light when you need it, consider the battery options available today before you make a purchase. The cheapest cost of battery power per kilowatt-hour is the traditional lead-acid battery, but who would want to lug a car battery to power a flashlight? The advantage of lightweight batteries must be compared to cost per kilowatt-hour of use and justified by convenience and frequency of use.
Types of batteries:
Primary (non-rechargeable) batteries
These are the standard AAA, AA, C, D and 9-volt alkaline units everyone is familiar with. Larger cell batteries provide a lower cost per kilowatt-hour than small cells, but their added size and weight is a disadvantage. The advantages of primary batteries are high energy density, long storage life and immediate operational readiness. No charging or priming time is required before use. Although secondary (rechargeable) batteries have improved, a regular household alkaline battery provides 50% more power than lithium-ion, one of the highest energy-dense secondary batteries.
- Lithium batteries lead the world in reliability and safety, providing long-term storage life (up to 10 years) at room temperature and long operational life over a wide range of operating temperatures. The superior chemical and design characteristics of these batteries are well recognized for both performance and power value.
The primary lithium battery used in cameras holds more than three times the energy of an alkaline battery of equal size. The down side to primary batteries is they don’t perform well when used at a high rate of consumption, and that’s when secondary batteries perform better. The most distinctive limitation of the primary battery is its one-time use, which makes is about 30 times more expensive than rechargeable batteries.
Secondary (rechargeable) batteries
Secondary batteries provide a far more economical source of energy than primary batteries, based on the initial purchase price and maximizing the number of discharge-charge cycles possible before replacement. Without proper and regular maintenance, the costs are significantly higher due to a shortened lifecycle.
- In terms of life cycling, the most enduring power cell is the standard nickel cadmium (NiCad) battery. In terms of stable capacity, internal resistance and self-discharge over many cycles, the NiCad battery deserves an “A” for almost perfect performance. The down side, is that Nickel-cadmium batteries have a moderate energy density, require periodic full discharges and contain toxic metals. NiCad batteries are more prone to memory problems. Memory shortens battery life in everyday use if not properly maintained. Applying a full discharge/charge cycle once a month solves this problem. If NiCad batteries are used on a daily basis, the full discharge/charge cycle should be performed every 30-charge cycles.
- Nickel-metal-hydride batteries perform well in their early stages, but past 300-cycles, they start to deteriorate rapidly. Nickel-metal-hydride (NIMH) batteries have a higher energy density than nickel-cadmium and do not contain toxic metals. Some experts maintain that Nickel-metal-hydride batteries are an interim step to lithium-ion. One advantage to NIMH technology is the lack of memory problems associated with NiCad batteries.
- In laboratory tests, the lithium-ion battery gets high marks because they offer the highest energy density and contain no toxic metals. The Lithium-ion batteries strong suit is that it maintains an almost constant capacity throughout the discharge cycle. With lithium-ion batteries you should avoid frequent full discharges because this puts additional strain on the battery. Partial discharges with frequent recharges are far better than one deep charge with the lithium-ion battery. Keep lithium-ion batteries cool, and avoid leaving them in hot places like a vehicle in the summer. Store at a 40% charge level.
Lithium-ion batteries have a lifetime of two to three years and the clock starts ticking as soon as the battery comes off the assembly line. For this reason, do not purchase extra lithium-ion batteries for future use, and always pay attention to the manufacture date.
After consuming this wealth of data you should be ready to select a flashlight or headlamp that is totally in tune with your personal needs for illumination. Before making your selection, check out Cabela’s Black Friday Sale and save!
Color is frequently used in the lighting industry to bring a bright, vibrant feel to an environment. Sports games, holidays, and raising awareness for a cause are just a few examples of where color comes into play with lighting. But did you know that each color carries meaning and has a subconscious effect on our everyday life? Now that the lighting industry is beginning to understand these effects, colored light is helping people all over the world.
Think of a commercial for baby products. The color white is almost always present. This is because white symbolizes the beginning of something, innocence, purity, safety, and cleanliness. These words are often associated with babies and new life. Therefore commercials with baby related products draw us in with subtle use of the color white, in turn putting all these words in our minds.
Just as white symbolizes certain things, the color blue also carries feelings of calmness, faith, and trust. Blue lighting has a special effect on the body in a variety of ways. Many findings show that the human eye has photoreceptors that are sensitive to blue light, which has an effect on circadian rhythm. Because of this blue light is good when waking up in the morning and helping a person readjust his circadian rhythm when traveling and suffering from jetlag. Blue LED lighting can also be used to increase blood flow, as the skin is also sensitive to the color blue, and can ultimately remove pain in the body and promote healing.
Green is also a calming color, conveying hope, soothing and healing. The color green is the most visible and sensitive color to the human eye. Green lighting was introduced into operating rooms in 1914 by Dr. Harry Sherman (read article) who found the color green reduces glare and complements hemoglobin red, the color of blood, to create a more visible environment for surgeons. Green light can also enhance learning and concentration, which is why it is sometimes used in classrooms.
Yellow is a warming color, which can evoke feelings of happiness or joy, as well as spark muscle energy and mental activity. The color yellow catches attention, which is why it is used often on taxicabs or school buses. In hospitals, warm tones of yellow lighting are used to create a relaxed and cozy atmosphere, which can help patients get to sleep at night.
Orange is a welcoming color, creating a friendly atmosphere. Some of the meanings behind the color orange are friendship, endurance, enthusiasm, and creativity. Orange lighting is perfect for bringing home a newborn baby, making them feel at home, welcome, and comfortable, considering red, orange, and yellow are some of the first colors a baby can see. It can also stimulate appetite in young people, which is why orange is associated with healthy foods. The color orange can also increase oxygen to the brain, therefore triggering increased mental activity.
Light purple generates feelings of wisdom, inspiration, and magic. Dark purple can deter people because it can be associated with sadness or frustration. In hospitals, a purple, or violet light, called “HINS-light” (read article) has been found to kill “superbugs”, like MRSA and C. difficile. According to researchers at the University of Strathclyde in Glasgow, Scotland, better sterilization and disinfection methods in hospitals are considered urgent needs, making this an important finding within the field.
Color subconsciously effects our everyday life. It is used strategically in retail, restaurants, schools, and hospitals to elicit a specific feeling in people. While each color has a separate meaning, they also each have a separate feeling associated with them, effecting our mood in everyday situations. Whether lighting is being used to enhance sleep patterns, cure jetlag, promote healing, or generate mental activity in the classroom, colored lighting is helping people all over the world.
What does the colour of a light bulb depend on?
I am going to answer this on the assumption you are talking about an incandescent lamp.
A tungsten filament is heated by the current flowing through it, and starts to behave like a black body radiator. Now a tungsten filament is not a perfect black body: the emissivity is a function of wavelength and has been characterized (see https://dspace.mit.edu/bitstream/handle/1721.1/4755/RLE-TR-328-04734719.pdf?sequence=1). From that paper, figure 29 is reproduced here:
This shows there is a weak relationship between emissivity and temperature – and that emissivity at shorter wavelengths is slightly higher (making the light “more blue”). Do pay attention to the vertical scale – variation is from roughly 0.42 to 0.48, which is why I call it a “weak” relationship.
This is a very small effect compared to the actual spectral characteristics due to the over all black body spectrum which is a strong function of temperature as shown in the following figure (“Black body” by Darth Kule – Own work. Licensed under Public domain via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:Black_body.svg#mediaviewer/File:Black_body.svg):
The equation represented here is Planck’s Law – it represents a victory for quantum mechanics because it explains why there is no UV catastrophe, although according to that link it was actually Einstein, not Planck, who made the connection…:
From this red-biased starting point you can now select certain wavelengths by filtering out certain components. An example of this is the GE Reveal light – when you look at the light bulb itself it has a blue-ish tint, and the light that it gives off looks “very white” – because it has filtered some of the yellow light to give a spectrum that looks more like sunlight (the surface of the sun is much hotter than a tungsten filament and gives off what we usually consider “white” light):
source of comparison: http://www.gelighting.com/na/business_lighting/spectral_power_distribution_curves/
Similarly, you can create any color of light bulb by filtering out the colors you don’t want. This filtering is very inefficient – you remove light from certain wavelengths which reduces the over all power of the light.
Fluorescent tubes typically use a different mechanism to create color. The gas inside the tube typically emits ultraviolet light, and phosphors on the inside of the tube convert this energy into longer wavelengths. Mixing the phosphors allows almost any spectrum (although the spectrum often has significant peaks, so that not all wavelengths are represented. This means that while the light may appear “white”, it may have a poor color rendering index).
LEDs and the Psychology of Light and Color
Posted on Jul 21, 2014 in LED Education | Comments Off on LEDs and the Psychology of Light and Color
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“LIGHT reveals the glories of the external world and yet is the most glorious of them all. It gives beauty, reveals beauty and is itself most beautiful. It is the analyzer, the truth-teller and the exposer of shams, for it shows things as they are.”
Edwin D. Babbitt, Principles of Light and Color
While interior design plans give plenty of attention to wall paint and floor colors, lighting plays a critical role that is too often overlooked. Color and lighting influence our psychological functioning and well-being on a day-to-day basis, and understanding these influences is important when creating “human-centric” spaces.
Designers have been using advanced color knowledge in this way for years, and the customizability of LED lighting now allows them to do the same with light. Let’s take a closer look at LEDs and the psychology of light and color.
Humanity’s fascination with color has been with us since the dawn of civilization, with different colors used to symbolize and express various moods in ancient artwork spanning from Greece to Tibet. Color theory can be somewhat subjective, as certain colors elicit varying reactions in individuals based on personal preference and cultural backgrounds. It’s a truly interesting scientific field, and a great deal of thought has gone into exploring the psychological effects of color.
One way of comparing colors in the visible spectrum is to divide them into “warm” and “cool” categories. The warm colors include red, orange, and yellow—think of the sun setting on the beach, or maple leaves strewn across the yard in early fall. These colors generally convey passion, positive energy, enthusiasm and happiness.
In contrast, the cool colors include green, blue and purple—think of a solitary walk on a full moon night, or the depth of the ocean sea beneath a sleeping fisherman’s boat. Those colors convey a sense of relaxation, reservation, intrigue and professionalism.
Given what we understand about how color impacts our mental state, it’s easy to see its importance in interior design. We can now, for instance, use different colors of LED lighting to shape the “feeling” in any environment. Let’s explore each color in terms of how it impacts the human psychological experience.
Red is the color of fire and blood. It is a stimulating color and is used by designers to heighten the senses. Red stands out, is never boring, and can even increase metabolism. Be careful though – red is also associated with anger and can be overwhelming or irritating to those who are easily stimulated.
It is also flattering to the skin, so if you’re looking to create a “sexy” LED lighting environment, red is a good choice.
Pink lighting is playful, feminine and warm. The color works well as an accent by adding freshness, energy and glamour to a room. Be careful with pink, as its eccentric nature may turn off some people if used excessively.
Friendly and approachable, orange is the color of happiness and innovation. Certain shades of the color are associated with changing seasons and the earth; using orange LED lighting commands attention and creates energy without the overwhelming feelings associated with red. This is a good choice for residential spaces where you want to make guests feel welcome.
Optimistic and uplifting, yellow activates memory and stimulates the nervous system. Yellow, especially the lighter shades, is also associated with happiness and sunshine. Installing yellow LED lighting will promote unity and communication as well as sparking creativity, making the color a good choice for commercial offices and the workplace.
Green, a neutral color, is associated with nature, and has a calming effect on the senses. It can also represent growth and new beginnings. Green has a balancing and harmonizing effect, and is very stable. Use green in a commercial office setting to convey feelings of wealth, stability, and renewal.
Blue conveys calmness, freshness, strength, and responsibility. The color is also connected to peace and has spiritual and religious meaning in many cultures as well. The meaning of blue changes dramatically depending on the shade. Light blues are relaxing, while bright blue can be refreshing. Using paler shades of blue can make a room feel more spacious. The color’s relaxing nature works well in the home, such as in bathrooms or bedrooms.
The color purple sparks creativity and will add an eccentric feel. It is moody, spiritual and enchanting; dark purples in particular give a sense of wealth and luxury, while light purples are associated with spring and romance. Using purple is an artistic choice, and provides a mysterious feeling to any space.
White is the color of innocence, purity and cleanliness. Due to its clarity, neutrality and resemblance to sunlight, white light is by far the most common lighting choice for interior space. Some people think white is boring, but anyone familiar with lighting will know this is not the case. There are a myriad of white lighting options available – Flexfire LEDs strip lights, for instance, come in warm, natural or bright white.
The Psychology of Color Temperature
Every light source, even white light, emits a characteristic known as “color temperature.” Differences in color temperature, which is measured in kelvins (K), account for the various shades of light we perceive and are closely associated with human psychology.
Lower temperatures (2,700-3,000K) appear as “warm” colors, such as yellow and orange. As these are the colors of light during sunrise and sunset, low color temperature often makes us feel relaxed and dreamy.
Higher temperatures (5,000K or more) appear as “cool” colors such as blue and green. Toward midday, light increases in temperature. In accordance with our body’s circadian rhythm, higher color temperatures increase our concentration and make us feel more alert.
Contact Flexfire LEDs to learn more:
Still have questions about how you can use light and color in your LED project? Contact us or give us a call at (925)273-9080.
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Other research suggests these light-sensitive cells also send messages to parts of the brain that play a role in mood and emotion.
“Light at night may result in parts of the brain regulating mood receiving signals during times of the day when they shouldn’t,” said Dr Tracy Bedrosian, a co-author of the Ohio State University study, in a university press release.
“This may be why light at night seems to be linked to depression in some people.”
And while the Ohio study suggests that shift workers could benefit from limiting their light at night from computers, televisions and other electronic devices, and increasing exposure to red light, the researchers say the advice applies to everyone.
“If you need a night light in the bedroom or bathroom, it may be better to have one that gives off red rather than white light,” Bedrosian says.
The Harvard researchers give more tips on healthy light use:
- Avoid looking at bright screens two to three hours before bedtime.
- If you work a night shift, or use a lot of electronic devices at night, consider wearing blue-blocking glasses.
- Expose yourself to lots of bright light during the day. This will boost your ability to sleep at night, as well as your mood and alertness during daylight.
If You See A Green Light On Someone’s Porch, You Need To Know What It Means.
Based on the 2014 United States Census Bureau there are 19.3 million veterans in the United States.
We often talk about how important veterans are. We all want to help and make them feel welcomed, appreciated, and respected. It is difficult to imagine that these brave men and women leave their families behind so they can serve and protect the families of complete strangers.
Their love for their country gives them the strength and courage to sacrifice their lives. As civilians it can feel trivial to thank a veteran. There are no words big enough to explain the admiration and high regards we feel for the hard work they do.
Nonetheless, their pain and struggle when they return to a regular life is real. Veterans often speak of feeling disconnected to daily life after spending months trying to stay alive and seeing things no human being should ever have to experience.
Many of the men and women who serve do not understand the impact and trauma of war. Returning home can make them feel isolated and overwhelmed.
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