On Wednesday, 27 February 2019 18:48:12 UTC, NY wrote:
"Rod Speed" wrote in message
...
Do bear in mind that the quality of light from a dimmed LED is
completely different from a tungsten bulb. They don't get
"warmer" as they dim.

They can do with the best designs like the Philips Hues.

No like some users they just get dimmer. You can change the colour of the
light though

I didn't know you could make the light get redder as it gets dimmer.
Obviously anything is possible because it's all under software control, but
I didn't know the software (eg the Android app) for Philips Hue bulbs could
be programmed to change the colour.

I can't say I've been too worried that the light doesn't get redder as it
dims, like a tungsten bulb does.

It;s not a worry more of a physical fact of life humans and animals have experienced since birth.

I have a variety of colours according to
mood etc (white for reading during the day to supplement daylight, warm
white for reading in the evening, "tropical sunset" for reading near bedtime
when I want to cut out blue light.

But ask yuorself why yuo;d want to do that.

Having set the colour, I just then change
the brightness as required. But it's nice to know that redder-as-it-dims (to
mimic tungsten) is possible if the need should ever arise.

If you don't know the reason for it then you won't change anything.


One thing that I'm always surprised at with LED bulbs used as room lights is
how bright the dimmest setting is -

On my dimmer there's a preset to adjust the minium level not that I:ve played with it much, but will do as the dimmest settign isn't as dim as I'd like, but if I make it dimmer the full brightness isn;t as bright as I;d like, for times when I drop something small on the floor and can't find it.



Given that LEDs are usually dimmed by altering the mark:space ratio of a
constant-frequency square wave, so the light is turned on for a
progressively shorter proportion of each cycler, it should be possible to
turn the LED on for less time to make it even dimmer than the present
dimmest setting.

It is but LEDs being diodes means they have a cut off point where they just don't come on at smaal mark ratios of less than about 5%.



I've always wondered how TV studios manage to dim the lights so faint
objects are visible (Tomorrow's World: "we'll just dim the studio lights so
you can see this oscilloscope trace") without them going red. I know they
leave a few lights on full brightness and kill the majority, so there aren't
any lamps on partial brightness, but even so, I'd have thought that as they
are dimming "the majority" you'd see them go a reddish orange.

Don;t forget that the cameras have AWB (average white balance, which has nothing to do with Harry posts) also camera also have a differnt spectral response to humans eyes too.