The Very-Many-Questions-Not-Worth-Their-Own-Thread Thread XLIII

[Samson]

Can someone explain this to me? I am no physicist, but is not higher kelvin hotter?

Dimmer switches let you control the lighting and are worth the effort and cost: bright when you need it and not so bright when desired.

Are they? Again, I am no physicist, but I have always thought that dimmer switches with incandescent bulbs must be spectacularly inefficient. In any situation where you have multiple lights you must be loads better turning some off rather than running them all cool, unless you are more interested in the "tempurature" of the light that the magnitude. LED dimmers work by switching the light on and off too fast for us to see I think so must be better as far as efficiency goes, but it still would seem to me better to turn some off than that.

 

[Birdjaguar]

I don't know about the efficiency, but would assume lower light levels mean less electricity used. I do not hink you need speical bulbs.

Here is one site selling the dimmer switches.

Dimmer Light Switches for your home | Smart Dimmers & Dimmers for LED Lights

Leviton's collection of light dimmers creates the perfect ambiance while reducing energy usage. Available in a wide variety of designs and capabilities -including LED & Smart Home.

leviton.com

 

[Cutlass]

Can someone explain this to me? I am no physicist, but is not higher kelvin hotter?

Are they? Again, I am no physicist, but I have always thought that dimmer switches with incandescent bulbs must be spectacularly inefficient. In any situation where you have multiple lights you must be loads better turning some off rather than running them all cool, unless you are more interested in the "tempurature" of the light that the magnitude. LED dimmers work by switching the light on and off too fast for us to see I think so must be better as far as efficiency goes, but it still would seem to me better to turn some off than that.

Color Temperature (Kelvin)

Color temperature is a characteristic of visible light and is stated in units of absolute temperature, known as Kelvin (K).

www.westinghouselighting.com

The kelvin rating is about matching the light color to the color given off by something heated to that temperature. So the hotter something is, the more it shades towards bright-white-blue.



A dimmer switch controls how much electricity reaches the light bulb. So it can't waste the electric current, as that current never reaches a place it can be wasted. But not all LED bulbs support dimmer switches, and you have to buy ones that specifically say that they do.

 

[Samson]

The kelvin rating is about matching the light color to the color given off by something heated to that temperature. So the hotter something is, the more it shades towards bright-white-blue.

Yeah, so why are the lower kelvins called hotter? "Warm Glow" = 2,000K - 2500K, "Cool White" = 4,500K - 5,000K. 4,500K is hotter than 2,000K.

A dimmer switch controls how much electricity reaches the light bulb. So it can't waste the electric current, as that current never reaches a place it can be wasted.

A dimmer switch on an incandescent bulb reduces its temperature. A lower temperature body emits a higher percentage of its energy below of the visible spectrum, primaraly infra red. If you have two incandescent bulbs and you want half the output if you turn one off you halve the electricity usage. If you reduce the voltage such that they are emitting half the amount of visible light you will not reduce the electricity usage much.

But not all LED bulbs support dimmer switches, and you have to buy ones that specifically say that they do.

That is what I said to start this sub thread. The point remains, if you have the number of bulbs that would be required in the chandelier posted above one could get a very similar effect by turning some off than making each flash really quickly, and then you would not need to buy ones that specifically say that they do which may be cheaper now and simplify maintenance down the line.

 

[Samson]

What's a good G9 LED lighbulb type to buy for a chandelier that will hold 8 such lightbulbs for a library/reading room? I am new to the "warm white" vs "daylight white" vs "bright white" etc lingo. What kind of white do I want? Or maybe I want a "warm glow" ?

Spoiler :

The chandelier I want takes G9 type of lightbulbs. This is what they look like

Spoiler :

This is what the chandelier looks like

Spoiler :

Given all this information.. what kind of lightbulb intensity would you get? Would a 6000K daylight white be too much? Would that basically be a bright white colour? It seems so, but would that be too bright? I want to avoid yellows and want something purely white. That seems better for reading. But please enlighten me

This is another "I do not get" thing. The images above of both the chandelier and the lightbulbs are very common, and to give a scale I shall assume 16 - 18 mm diameter for the lightbulbs as per this. Those spheres are I guess much bigger than that, perhaps 100 - 200 mm?

My understanding is that the primary failure mode of LED lightbulbs is thermal degradation of the circuitry caused by heat generated by the diodes. One of the best ways to protect the circuitry is to thermally separate the LEDs and the circuitry components. If one has 100 mm this is easy, just put them on different bits of a piece of metal that air can circulate around. If one puts both LED and circuit in a bit of plastic with a diameter of 16 - 18 mm then it is almost impossible, and one will expect have have to change these bulbs at some point, with a frequency somewhat dependant on the air flow around them. Why do they constrain themselves so much, to the apparent detriment of both the consumer and the environment?

Spoiler I think they should look more like this but with more angle iron :

 

[Bonyduck Campersang]

eah, so why are the lower kelvins called hotter? "Warm Glow" = 2,000K - 2500K, "Cool White" = 4,500K - 5,000K. 4,500K is hotter than 2,000K.

I assume it's referring to the colour not the temperature? Red, yellow colours are considered 'warm' while white, blue colours are considered 'cool'

 

[Comrade Ceasefire]

I assume it's referring to the colour not the temperature? Red, yellow colours are considered 'warm' while white, blue colours are considered 'cool'

An annoying pedantic person (nope, not me) would say, "Depends on the culture, I suppose".

Some cultures, for example the Indigenous Candoshi of Peru, don’t have the category word “color” in their language, so it is impossible to ask, “What color is this?” Instead, one has to ask, “What is this like?” If the answer is “it is like ripe fruit,” is that an expression of color, or not? Opinions differ and may depend on the cultural expectations of the person doing the study.

Over the Rainbow: How Culture Shapes Color

Over the Rainbow: How Culture Shapes Color | Atmos

In the Western world, we are taught that the rainbow has seven colors. But science shows that culture and language shapes our vision.

atmos.earth

 

[Birdjaguar]

From your link above @Comrade Ceasefire !!

"A final variation is that some people can see past the end of the rainbow into the ultraviolet, just like bees, butterflies, and other insects. It turns out that the human cones and brain can detect ultraviolet light, but our lens usually filters it out. Some people who have had cataract surgery, in which the lens is either removed or replaced with an artificial substitute, start to “see” ultraviolet.

This happened to researcher Bill Stark, who suffered an eye injury when he was 10 and had cataract surgery at age 12. His new superpower later proved “convenient,” he said, for his academic interests in fruit fly vision. “What does UV light look like? Actually, it looks [like] a desaturated (whitish) blue,” he once wrote on his webpage. The same thing also happened to famous French painter Claude Monet, which is likely why his palette became bluer in later life."

 

[Comrade Ceasefire]

From your link above @Comrade Ceasefire !!

"A final variation is that some people can see past the end of the rainbow into the ultraviolet, just like bees, butterflies, and other insects. It turns out that the human cones and brain can detect ultraviolet light, but our lens usually filters it out. Some people who have had cataract surgery, in which the lens is either removed or replaced with an artificial substitute, start to “see” ultraviolet.

This happened to researcher Bill Stark, who suffered an eye injury when he was 10 and had cataract surgery at age 12. His new superpower later proved “convenient,” he said, for his academic interests in fruit fly vision. “What does UV light look like? Actually, it looks [like] a desaturated (whitish) blue,” he once wrote on his webpage. The same thing also happened to famous French painter Claude Monet, which is likely why his palette became bluer in later life."

They are induced by traumatic changes to the eye. I've read a few articles about the phenomenon known as tetrachromacy which is fascinating.

The women with superhuman vision

A tiny group of people can see ‘invisible’ colours that no-one else can perceive, discovers David Robson. How do they do it?

www.bbc.com

 

[Valka D'Ur]

I assume it's referring to the colour not the temperature? Red, yellow colours are considered 'warm' while white, blue colours are considered 'cool'

In one of his science essays, Isaac Asimov mentioned a mnemonic for the order of stars' spectral types from hottest to coolest: OBAFGKM ("Oh, Be A Fine Girl/Guy, Kiss Me"). O = white and M = red. Our own Sun is a G star, so we're fairly cool, but not as cool as the orange K stars or the red M stars.

From your link above @Comrade Ceasefire !!

"A final variation is that some people can see past the end of the rainbow into the ultraviolet, just like bees, butterflies, and other insects. It turns out that the human cones and brain can detect ultraviolet light, but our lens usually filters it out. Some people who have had cataract surgery, in which the lens is either removed or replaced with an artificial substitute, start to “see” ultraviolet.

This happened to researcher Bill Stark, who suffered an eye injury when he was 10 and had cataract surgery at age 12. His new superpower later proved “convenient,” he said, for his academic interests in fruit fly vision. “What does UV light look like? Actually, it looks [like] a desaturated (whitish) blue,” he once wrote on his webpage. The same thing also happened to famous French painter Claude Monet, which is likely why his palette became bluer in later life."

Both my eyes have an artificial lens. And holy crap, I have seen colors I never knew existed. It's really disorienting.

The article mentions something about men not perceiving colors the same way that women do. I'm reminded of when the local SCA group decided to make banners for our respective officers. We made a list of every color we needed, and went off to the fabric store. The women in the group were all crafters and used to differentiating between very subtle shades of colors (since we worked with yarn, embroidery floss, thread, etc.). The lone guy in the group kept pointing out different bolts of cloth and saying, "How about this one?" and he soon became really frustrated when we'd tell him that it wasn't remotely the right shade of whatever we were looking for.

 

[bene_legionary]

Isaac Asimov mentioned a mnemonic for the order of stars' spectral types from hottest to coolest: OBAFGKM ("Oh, Be A Fine Girl/Guy, Kiss Me").

Oh why I am not surprised that's a mnemonic he created.

Nonetheless, this could be very useful for me. I'm... planning to write/assist in writing some stories for a sci-fi game in the near future (after these midyear exams).

 

[Valka D'Ur]

Oh why I am not surprised that's a mnemonic he created.

Nonetheless, this could be very useful for me. I'm... planning to write/assist in writing some stories for a sci-fi game in the near future (after these midyear exams).

Asimov didn't create it. He mentioned learning it in one of his university classes.

Origin of spectral type mnemonic

I've found it useful over the years.

 

[Gori the Grey]

What's a good G9 LED lighbulb type to buy for a chandelier that will hold 8 such lightbulbs for a library/reading room? I am new to the "warm white" vs "daylight white" vs "bright white" etc lingo. What kind of white do I want? Or maybe I want a "warm glow" ?

Some home stores (my Home Depot, eg) have a display at the spot where they sell the bulbs that has one of each category, so that you can compare the quality of light from each. I myself favor warm.

 

[Comrade Ceasefire]

Some home stores (my Home Depot, eg) have a display at the spot where they sell the bulbs that has one of each category, so that you can compare the quality of light from each. I myself favor warm.

I often get up after sunset (aka "The Nosferatu Crawl"), so I'd go for the one that encourages vitamin D production.

 

[Samson]

I often get up after sunset (aka "The Nosferatu Crawl"), so I'd go for the one that encourages vitamin D production.

Vitamin D production is UV light, and you do not really want that from your light bulbs.

 

[Gori the Grey]

Not unless under the care of a physician, taking the place of 15 minutes of daylight:

UVB Light: Vitamin D and Light Therapy Treatment - LightSources

High-quality, long-lasting UVB bulbs custom engineered to meet a variety of applications that require specific wavelengths of UVB light.

www.light-sources.com

 

[Farm Boy]

15 minutes.

V Rising is pretty decent for a little isometric survival/crafting lark. I'd wait for a sale, personally.

 

[Samson]

Vitamin D does come in pills. What may also be relevant is the frequency sensitivity of intrinsically photosensitive retinal ganglion cells (ipRGCs) which wiki says is between 460 and 484 nm. These are newly discovered photoreceptors that are thought to be important in controlling our circadian rhythm.

 

[Cutlass]

This is another "I do not get" thing. The images above of both the chandelier and the lightbulbs are very common, and to give a scale I shall assume 16 - 18 mm diameter for the lightbulbs as per this. Those spheres are I guess much bigger than that, perhaps 100 - 200 mm?

My understanding is that the primary failure mode of LED lightbulbs is thermal degradation of the circuitry caused by heat generated by the diodes. One of the best ways to protect the circuitry is to thermally separate the LEDs and the circuitry components. If one has 100 mm this is easy, just put them on different bits of a piece of metal that air can circulate around. If one puts both LED and circuit in a bit of plastic with a diameter of 16 - 18 mm then it is almost impossible, and one will expect have have to change these bulbs at some point, with a frequency somewhat dependant on the air flow around them. Why do they constrain themselves so much, to the apparent detriment of both the consumer and the environment?

Spoiler I think they should look more like this but with more angle iron :

Different nations have different electrical systems. But, so far as I know, the Canadian one is pretty much the US one. The standard lightbulb, as a retrofit into legacy lighting fixtures, has about a 50mm bulb size. Although some are half that. 100 and 200mm pretty much don't exist. I had to hunt, and eventually use Amazon, to replace a 150mm bulb. Because most LED bulbs are screwing, snapping, inserting, into existing fixtures.

 

[warpus]

On the question of door knobs.. stainless steel vs zinc with a satin nickel finish? Is it pretty much a personal preference or is there more to it? Does one rust faster than the other, does it last longer, etc.?

The only difference I see visually is that the stainless steel door knobs/handles are a bit more shiny. The satin nickel finish ones appeal to me more, it comes off as being a bit less tacky, if I dare to describe how I feel. But am I missing anything?

I am replacing all 5 door knobs on my upper floor and want to go with something that looks nice but also works well and lasts a while. This is what I've found so far, I like the way it looks. Just not sure if it's the material & finish I want. What says you?

Follow-up Question:

I found a set I might want to buy (click to see), but I'm confused about something. It says that it's "zinc satin nickel" but when you scroll down to product specifications, you see these 2 categories listed:

Color/Finish Family: Stainless steel
Manufacturer Color/Finish: Satin nickel
Material: Zinc

What's the difference between color/finish family and manufacturer color/finish? Where is the stainless steel hiding in this product?