Ideas for changing the color temperature of these LED work lights. Will this work? Or is there a better way?

Is there a passive option? Like, I can apply some kind of material to filter out the yellow?

That's a long way to go to get the right colour temperature - and then again, maybe it's also worth paying attention to CRI as well. It will probably work assuming all is well, but prolonged heat will soften/char the FR4 substrate and doing it in sections may cause warpage that may potentially affect the connection reliability (because the "shape" of the PCB is changing due to differential heating/cooling).

An optical filter may be possible - but you will cut down on the light quite a bit using something like a cool filter. Camera custom white balancing with a grey card generally works as long as you don't then have something active (e.g. an LCD screen) in shot that has its own colour temperature.

- Gough

Perhaps just grab a set of fluorescent tube replacement LED tubes and run them "in front" of said fixture ... or gut them ... as a quick fix? Not sure about the quality of the LEDs in those but that would be what I would be tempted to do ... or just get a whole different fixture.

- Gough

Gough Lui said:

Camera custom white balancing with a grey card generally works as long as you don't then have something active (e.g. an LCD screen) in shot that has its own colour temperature.

You mean ... like in every video I shoot?

The ultimate challenge with color correcting is that exposure isn't constant when moving the camera around. I can't shoot the reference card every time. (and I'd like to move towards more inpromtu shooting.)

But, aside from that, I don't like the warm temperature when soldering or inspecting something anyway. So it's a double dislike.

Hi James,

I too think it could be a partially CRI issue as well. I'll ask a friend tomorrow for his opinion (he's a cameraman for a national broadcaster). I know he's suggested full color LED lights to me in the past, but I didn't ask him about task lighting. In your case it is task lighting as well as video lighting.

What video tool do you use by the way? It may have an option to do automatic color-correcting. With Davinci Resolve, it is automated. You can use a color test chart (they cost about $60 upward) and as long as you have a snippet of video with that test chart in view, then the software will be able to color-correct, and that will work for a range of colors, since it's more than a simple warm/cold adjustment.

Yeah, that's part of what I am debating. Just build my own light.

I really like the fixtures. They mount cleanly to the benches and provide the right amount of coverage. I just hate the temperature.

baldengineer said:

exposure isn't constant when moving the camera around

Well, with custom white balance, I set it once for the light I'm using and then it's kept as a setting on the camera. Otherwise, I use white balance corrections in post (in a way, similar to Auto Colour in Premiere Pro).

Unfortunately, this becomes very problematic when LCD screens are around since many are backlit at about 6500K, so if I correct for my 2700K source, it looks horrible. Alternatively, correcting for the screen means the background is horrible.

(White balance corrected for LCD, but room lighting 2700K makes everything look orange)

(Room lit by 2700K source as above, but since no active source of light at any other colour temperature, I custom white balance adjusted on the grey ESD mat and all looks well)

It's a problem I'm starting to fight with too ... especially since RoadTest sponsors would like to see video ...

- Gough

To expand on my other response, the complication is that the temperature difference between the overhead (spot) and other lights (key/fill) cause a lot of color correction problems. I know most people don't catch it, but it is something I see. E.g., a breadboard's white is completely different from an instrument's front panel white. So I have to either do a bunch of masking or pick an in between.

But more than that, everything in my lab is very cool white, except the work benches. So even outside of videography, I don't like the temp.

CRI is something I had not given much attention to before, so I'm quickly understanding how that plays a role!

I see.. that does cause problems, if there is a mix of color temperatures in the room! In that case there's nothing to be done other than modify one or the other to match, or to turn off one of them.

It looks like it might just be FR4, so that should work to remove the LEDs and attach new ones.

I tried to make my own LED board too (out of FR4). I had to pause to work on a RoadTest, so it's been in limbo but I should try to solder the LEDs at some point. I too am going to use a pre-heater and hot air tool, but I might use low-temp solder because I've never used hot air for LEDs before and I don't know that I trust myself with it too much. A reflow oven might be safer. I've procrastinated quite a bit, in part because I can't decide how to approach the soldering exercise.

These panels are for warm and cold LEDs (its for this PicoChroma project I attempted at the start of the year).

Hmm, maybe using hot air to solder LEDs is a bad idea, especially when their color output is important.

Maybe I will use hot air to remove the existing LEDs but pencil solder in the new ones.

Also, I was planning to test a strip with the various LEDs I bought. Perhaps I could do an A/B test of hot air versus pencil tip.