Kelvin value for night time?
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@zikzak I'm using a Rosco Supergel #23 Orange. There might be something better, maybe the #22 or #25, but that's what they had in the shop near me. They give spectrum charts for every filter, on the website. It's quite easy to find, a good photography shop should have it. I paid about $10 for a large roll because I wanted to try putting it over my screen, but that didn't work out so well. Anyway, now I have a lifetime supply. I like the colour, it gives a sort of campfire effect, and I can still make out the colours of things in my room.
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@Elhem-Enohpi I'd say 200 lumens (and yes 400 is too much) because it's still a lot of light. If you can see fairly well at most brightness levels, than most should be able to adjust to 200 lumens. I think any lower and people would just freak out because it's so dim, they just wouldn't feel comfortable, so then they don't sleep well!
I just like the number because it's about what most 120v 25 watt incandescent bulbs put out, so it's easy to try. 12 volt 25 watt bulbs can get up to almost 400 lumens! I saw one by "Bulbrite" that got 375! That is truly insane.
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@Elhem-Enohpi That's great! I just ordered a sample pack of Lee filters - it was free with free shipping also (I'm located in Denmark).
http://www.lightpartner.dk/lee-filters-provebog-designers.htmlI can can then check the different amber tones - thanks for the tip! I actually bought some filters before but they were too red for my liking and I kinda gave up because I didn't know exactly what to buy - but with these samples I can get to know what I want :)
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@zikzak So many to choose from!
If you download the PDF datasheets for the Lee filters, they show you a chart with the percentages they block for each wavelength. You can compare that with the melanopic response of the eye:
I looked at a couple, the #020 Medium Amber seems like it might let a bit too much green through, but it could be ok depending on the bulb and the other factors. The #507 Madge cuts off everything shorter than about 560 nm, so that should certainly do the trick on any bulb. The #105 Orange has more yellow and a little bit of green. It's similar to the Rosco #23 Orange that I have, and close to the Uvex SCT Orange filter in the f.luxometer, though with slightly more in the 520 nm area. The Uvex brings the Cree 2700K at 100 lux to an acceptable level according to the f.luxometer. If you're putting it over a 2700K bulb, a lot of the blue has been removed already.
Let us know how the experiment goes!
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@Tungsten_smooth Ok, I thought maybe you had figured out the melanopic lux exposure a 200 lumen incandescent bulb would produce in an average room. That could actually be useful to know. So it's more of a guess then. By the way, I did calculate that a full moon actually produces about 120 quadrillion lumens. Just goes to show you that it's the lux that counts. Otherwise I guess it would be called f.lumens.
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@Elhem-Enohpi Ah yes, lux is much more meaningful than lumens! Lumens is basically at the source, and lux is what you see, which can be 1/5 or less the originating source.
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@Tungsten_smooth It can be 1/120 quadrillion, if the originating source is 363,104 km away! A full moon produces maximum 1 lux on Earth.
If it's not focussed into a beam, a light's brightness drops off with the square of the distance. A light ten feet away is only 1/100th as bright as it is one foot away. That's not counting all the light bouncing off the walls and objects of a room though, which is more difficult to calculate.
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@Elhem-Enohpi Oh wow, that's a huge difference! I've read herf mention it several times, but I'm not sure how to calculate it. 10 feet makes a difference of 100x! That's just crazy, and a really good thing.
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@Tungsten_smooth It's true if there's nothing else reflecting the light towards you, like looking up at a light in a dark sky.
If you're in a room, a lot of light is bouncing around. You basically need a computer simulation that knows how reflective everything is to calculate it then, like the "raytracing" that computer graphics and video games do.
Or, measure it with a light meter.
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@Elhem-Enohpi I think a dim light keeps walls quite dim. Not too dark, but dim enough to say that I don't worry about it's affect on sleep. I'll usually cut down to 20 watts or less of incandescent light. I have moderately dark walls, and I block out all the light tresspass from the streetlights. I guess it would be interesting to know how many lux I see in different locations but I know that it's below 15.
In the daytime (right now!) with more than one window in my room, I've got 13 lux measured to the ceiling. It's sunny but it's not noon, I'll top out at maybe 35. That's really dim--so I have no doubt that a dim light will be considerably less.
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@Tungsten_smooth What are you measuring that with?
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@Elhem-Enohpi Note 3 light sensor.
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So I messed around with the filters - there are some nice possibilities. But it'll cost me too much anyway if I'm gonna put on dimmers. So I'll go with some more Hue bulbs. After all they are very convenient. I stumbled over this - and it sounds quite good since my purpose with them is mainly night lighting:
herf f.lux team
4 months ago
The Hue is RGB, so it's more like a computer monitor than like a warm-white/cool-white mixture.I have some data that suggests the Hue is generally extremely low melanopic impact - so for an equivalent color temperature, it has less impact than lights that look similar.
This makes it hard to get a good daylight from it, but for night time lighting it is extremely good. The red is over at 626nm, so a red setting on Hue shows no blue light at all.
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@zikzak According to f.luxometer, a Hue set to 2700K has slightly less melanopic lux than a 2700K Cree LED or a standard incandescent of the same brightness, but slightly more than a CFL bulb. The difference isn't really significant. So I don't think I'd agree that the Hue has "generally extremely low melanopic impact", it seems about the same as other lights with equivalent colour temperature.
As I said though, I have no experience with the Hue. It seems terribly expensive to me, don't they cost around 500 DKK per bulb? A 120x50 cm sheet of Lee filter on that site is 68 DKK, and a normal dimmer switch that can do multiple bulbs is maybe 100 DKK or so, no? Certainly less convenient though, if money is no object...
I can't read what you wrote that you stumbled across, something posted by herf?
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The thin that herf wrote was this: "The Hue is RGB, so it's more like a computer monitor than like a warm-white/cool-white mixture.
I have some data that suggests the Hue is generally extremely low melanopic impact - so for an equivalent color temperature, it has less impact than lights that look similar.
This makes it hard to get a good daylight from it, but for night time lighting it is extremely good. The red is over at 626nm, so a red setting on Hue shows no blue light at all."
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And yes Hue is very expensive - but dimmers a quite expensive also - they are around 250 DKK for the ones implemented in a switch. The ones you can put in the cord are cheaper but makes a hissing sound and usually of mediocre quality. But still Hue is expensive - usually they go for 1000 DKK used for a set with 3 bulbs. That is pretty decent. And the versatility you get is pretty nice I think. Different colors, dimmable, turns on/off when you leave/come home etc. is actually quite usable although I didn't think I was gonna use it to start with.. One annoying thing is that you can't set a custom color/brightness when you turn them on from a switch...
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@zikzak No idea why he would say that, since his own f.luxometer data shows that it actually has more melanopic impact than a CFL bulb of the same brightness and colour temperature. If you dial it down to red-orange, that's different.
You can get cheap in-wall dimmer switches for half the price you mentioned if you shop around, I don't know about the quality though. I don't use them. I suppose it would be nice if my lights would magically dim and change colour, but it's a luxury I can't justify on my budget.
A friend paid a lot of money for the original Hue lamp years ago, and was constantly fooling around with adjusting the colour from purple to green or whatever. I found it quite annoying. Thankfully the novelty wore off and it doesn't get used anymore. Sometimes versatility is overrated...
My main concern is not to be kept awake at night. Switching to the small orange-filtered lamp a couple of hours before bed seems to be fine, and the colour is pleasant enough. It's a cheap and simple solution. I don't worry about the lights in the hallway etc., because I don't spend enough time there for it to make a difference.
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@zikzak You can get a plug in lamp dimmer from Lutrom for $10 USD. You can get a rotary dimmer that goes into the wall switch for less than $10 USD. Prices may vary by location, but you should be able to find these things for very low prices.
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Thanks guys.. Haha I feel like I'm going over to the enemy with Hue ;) Anyway I found a starter set for 750 DKK - half price. Maybe I can even sell the hub thing for 100 DKK - so a pretty good deal. And I do like the Hue - I don't mess too much around with it - I just have 2 or 3 settings I like.. The fact that you cannot turn it on from a physical on a specific setting i just stupid though..
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@zikzak said:
Thanks guys.. Haha I feel like I'm going over to the enemy with Hue ;) Anyway I found a starter set for 750 DKK - half price. Maybe I can even sell the hub thing for 100 DKK - so a pretty good deal. And I do like the Hue - I don't mess too much around with it - I just have 2 or 3 settings I like.. The fact that you cannot turn it on from a physical on a specific setting i just stupid though..
F.lux is designed to work with Philips Hue. It's in the "Extras" menu.
