Re: [Avid-L2] Phillips Hue lights for a monitor backlight?

But due to the low power requirements of LED and their requirement for DC its possible to rectify and smooth AC to DC and have no flicker.

Pat Horridge

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From: Avid-L2@groups.io <Avid-L2@groups.io> on behalf of Dave Hogan via Groups.Io <mactvman=yahoo.com@groups.io>
Sent: Saturday, December 28, 2019 12:59:06 AM
To: Avid-L2@groups.io <Avid-L2@groups.io>
Subject: Re: [Avid-L2] Phillips Hue lights for a monitor backlight?

 

Yes, as mentioned in my notes, LED bulbs share the same effect as fluorescents...they are subject to the frequency of their power source.  Because of their fast response to electricity they actually turn on and off as the AC circuit voltage swings on and off.  Therefore the makers for photographic lighting (motion and still) need to provide a high frequency source, just like in fluorescent lighting.

However, they aren't using a ballast, which often malfunctions, and makes fluorescent lights flicker worse than line frequency.

Dave Hogan,

Burbank, CA

On Dec 27, 2019, at 4:49 PM, John Moore <bigfish@pacbell.net> wrote:

This is interesting because if anything I have had more flicker and spectrum issues on shoots that have used LED lighting.  Perhaps the technology has improved but I was told by many that the spectrum of LED fixtures was very notched and one Lighting Director I know had to use a mixture of different LED fixtures to maintain a better color temp.  I've heard that you can dial in color temperature on some of the LED lights now.  Perhaps my friend was working with older LED lights but this was two or 3 years ago on a major cable talk show that he was the Lighting Director on.


On Fri, Dec 27, 2019 at 02:17 PM, Dave Hogan wrote:

The other problem with fluorescent lighting is that the CRI starts degrading right away and continues over the life of the unit.  They also have to "warm up" to get to their proper color temp.

 

LEDs on the other hand maintain their CRI throughout most of their much longer lifespan, and have no warm up period.

 

Thus fluorescent lights have a much higher maintenance cost, and unless you have high end monitoring equipment, you don't know what your color temp will be a week after you put them in.

 

The flicker issue can occur on cheap LED light sources too, they need to use high frequency sources as well.

 

And while we are on the subject of CRI…Fluorescent bulbs have spikes in their color range that have to be controlled with phosphors, whereas LEDs generally have a wider smooth range of light output.

 

LEDs are the way to go in every category, from quality of light, consistency and power savings.  LEDs do have a higher up front cost, but due to their much longer lifespan and greater power savings they are cheaper to operate.

 

My .02

 

Dave Hogan

Burbank, CA

 

On Dec 27, 2019, at 1:35 PM, Pat Horridge <pat@horridge.org.uk> wrote:

You need to go for High frequency fluorescent. They multiply up the frequency to make the flicker much less noticeable.

Pat Horridge

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From: Avid-L2@groups.io <Avid-L2@groups.io> on behalf of John Moore via Groups.Io <bigfish=pacbell.net@groups.io>
Sent: Friday, December 27, 2019 9:24:47 PM
To: Avid-L2@groups.io <Avid-L2@groups.io>
Subject: Re: [Avid-L2] Phillips Hue lights for a monitor backlight?

 

A fellow editor told me he tried some fluorescent back lights and they flickered or made the monitor appear flickery.  He found one little fluorescent fixture that didn't seem to flicker.  I don't know what aspects of a fluorescent tube that would effect it's flickeryness and I wonder if it would depend on AC line frequency vs. monitor frame rate/refresh rate.


On Fri, Dec 27, 2019 at 03:39 AM, bouke wrote:

Or, why not use fluorescent tubes?

Those are dirt cheap, can have (if you spend a few buck more) a high CRI, produce close to no heat, and can be dimmed with pieces of gaffer tape if needed.

 

Can someone explain why a high CRI is important when the puropse is to the light a one-color wall? I would think the wall only reflects the color it was painted in.

So if that particular color is missing / lower in the light source, it simply would not come back. (And you have a free dimmer :-)

 

 

Bouke

Edit 'B / VideoToolShed.com
van Oldenbarneveltstraat 33
6512 AS  Nijmegen
+31 6 21817248

On 27 Dec 2019, at 12:20, Pat Horridge <pat@horridge.org.uk> wrote:

Isn't it better and safer to just get 6500K bulbs? And you want a CRI that's as wide as possible.

Re dimming I'd be temped to use ND gel to dim if needed as its less likely to alter the colour temp.

 

 

Pat Horridge

 

From: Avid-L2@groups.io <Avid-L2@groups.io> On Behalf Of John Moore via Groups.Io
Sent: 26 December 2019 23:07
To: Avid L-2 Groups IO <avid-l2@groups.io>
Subject: [Avid-L2] Phillips Hue lights for a monitor backlight?

 

In my recent DolbyVision mastering class it was mentioned that the Phillips Hue Bulbs can be adjusted to proper color temperature for a monitor back light.  It says in the various info I've obtained that the White Ambience Bulb is controlled by blue tooth and it can have a color temp of 27002K to 6500K.  I picked up a couple lights and got them working.  The interface on my new iPhone, yes I finally retired the BlackBerry Torch, and I can swing the color temp but the interface is not set up with a degree Kelvin parameter.  It's either choose a preset or move the icon in a circle with the bottom going more blue white.  I'm assuming the bottom of the circle would be approx 6500K.

 

Anybody played with these bulbs using a real color temp meter or know if there is a way to get a preset that is designed to set the bulbs to 6500K white.

 

They also have dimming and I'm wondering it the dimming would effect color temp.  I know it did on tungsten lamps on the stage.

 

 

John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net