Monday, March 04, 2019

New life for old worklights

Who doesn’t love it when a plan comes together? Upgrading my studio lighting for photography and video—and more—has been on my list for a long time, and yesterday I finished a major part of it, converting my old halogen worklight into and LED system. It was a good result.

Last August, I talked about wanting to come up with cheap lighting solutions for videos (and also for studio photography). I said, “I wanted to make it as cheap as possible, or, even better, to use things I already have,” and today’s project actually did both.

The photo montage up top shows the old worklights (also known as “shoplights”) I’ve had for maybe 15 years, on the left. Basically, the project involved swapping out the old halogen bulbs for LED ones. There were several reasons I wanted to do that, and some challenges along the way, but the project was successful (lower right photo in the montage). I mention all that up front so that anyone who wants all the details can continue on, while those not interested in such things can be satisfied with knowing the project was successful. The rest of this post is about the whole story, from the background through to the completion, and also some technical information about it all.

I bought those worklights when we lived in Paeroa because I needed bright light when I was working on our house, which we were renovating. The lights were relatively cheap (less than $50, I think), which was good. However, they had two 500 watt halogen bulbs which used a lot of power and, like all halogen bulbs, were hot—in this case, VERY hot. The upper right photo in that montage shows the warning notice on the top of each fixture, that they get hot, so hot that, as a little picture indicates, everything and everyone should stay at least one metre away from the thing when it’s on. Each one of the fixtures has a little handle to make it possible to adjust the lights’ positions without touching them—well, theoretically, maybe, because I found even that too hot to touch.

The fixtures got so hot that it was impossible to keep one of them locked in place, and it kept flopping forward when it was on. Eventually, it broke the halogen bulb and it no longer worked. That was kind of a relief, really, and I used only the one after that.

We moved away from that house in 2006 and I didn’t use the lights again until I needed to shoot photos of things we were going to sell online, and the lights were perfect for that. When I became interested in making videos, I thought again about the worklight rig, but I was concerned about how hot they got. About that same time, I saw a YouTube video made by some young New Zealanders explaining how they made their videos, and for lighting they used a bunch of the single-fixture models that sit on the floor. But they get just as hot.

I knew that the advantage of halogen was that it was generally flicker free (unlike many compact fluorescents), which is important because sometimes flicker can be seen in videos. Halogen lights also generally have cool colour, which is important for both video and a lot of photography. But have I mentioned how HOT they get?

Time passed, I got busy with other things and with life. By the time I was ready to go again, LEDs were becoming much more common, and I thought that could be an option.

The first problem was cost—LED double worklights, similar to what I already had, were more than double the price of new halogen ones—sometimes three times the cost. They were also relatively low in light output and were warm white, which was of no use.

A little digression is needed. Old-fashioned lightbulbs were always referred to by their watts, like a 60 watt bulb, for example. But that was only a measure of power consumption, and we all just knew that the higher the wattage, the brighter the light from the bulb. However, watts are never a measure of light output, or the colour of the light.

Light output is measured in lumens, and the minimum lumen rating is now included on packaging for light bulbs to make it easier to compare the output of various kinds. For example, a 75 watt old fashioned lightbulb produces a minimum of 1,100 lumens, as does a 30-52 watt compact fluorescent, and a 10-16 watt LED. By focusing on the actual light output—the lumens—we can fairly judge the relative brightness of different kinds of lights.

The other thing that matters in lighting for videos and photography is light colour temperature, which is expressed as temperature in degrees Kelvin. The lower the number, the redder (or warmer) the light, and the higher the number, the bluer (or cooler) the light. For both video production and a lot of studio photography, the goal is to mimic daylight on an overcast day. The temperature of that daylight is about 6500K. A standard lightbulb is around 2400K or so.

When I had a 35mm film camera many, many years ago, I couldn’t afford photography lights (they’re still really expensive, actually), and I had to use ordinary lightbulbs. The reddish light gave my subjects an orange tinge. So, I bought a special blue filter for my lens which corrected the colours (these days I can usually accomplish the same thing in Adobe Photoshop).

Putting all that together, the LED worklights used to be too dim (not enough lumens) and too warm (too low in K). Old-fashioned lightbulbs could be bright enough, but they, too, were too warm and generated heat (plus, I really didn’t have anything suitable to use them in—clamp on lights for workshops seem to have disappeared). Compact fluorescents were available in versions both bright enough and cool enough in light colour, but they also often flicker, something that matters for video, where that can sometimes be seen. Halogens, well, have I mentioned how hot they get?

I knew that companies were starting to make LED replacement lamps (“bulbs”) that would work in a worklight. Only trouble is, I could only find them in the USA, where they ran only on 120 volt power supply (we’re 220/240 volts in New Zealand).

More time passed, and the bulbs became available here—at a very high price: A single replacement bulb often cost more than a new worklight. Moreover, they were also warm white, which was too red for what I wanted. What was the point of that?

New LED light, left, and an old broken
halogen on the right. The LED's "dots"
face down, toward the reflector.
Still more time passed, and new fixtures became available that were much brighter, had much cooler light, and were much cheaper (though still far more expensive than the old double halogen rigs had been). A range of bulbs also became available, most of which were warm white, but I found one that was listed as “cool white” (it’s in the photo at right, alongside one of the old and broken halogen bulbs). At 6500K, it’s actually daylight (also sometimes called “cool daylight”). Perfect for what I wanted. The bulbs are 1521 lumens each, which is a bit less that an old 100 watt lightbulb, enough for most of what I want it for. I bought two (and together, the lumens roughly double).

At $22 each (or $44 for the pair), the LED bulbs cost me less than the price of a totally new double worklight, but two new halogen bulbs would have cost me about $12 for the pair. In fact, the store sold six packs of halogen bulbs that cost about as much as the two LED replacements I bought. Clearly cost is still an issue. On the other hand, the replacement bulbs should last dramatically longer than a halogen bulb, so maybe halogens aren't really as dramatically cheaper as they seem?

When I got home, I went out to the garden shed and got the worklights, finding that when we moved to this house two years ago, the movers had taken it apart. First step was to put it back together. The thing was filthy—too many years without being used, including two out in the shed, and the paint was starting to peel in places.

When I opened the fixtures to replace the bulbs, I also took out the glass to clean it. Technically, I don’t need the glass anymore because the bulbs aren’t as fragile as the halogen ones were. However, if I ever want to the change the colour of the light, I can use the glass to help hold filters, which are similar to cellophane. The wire cages, which were originally to keep the user from being burned from touching the glass, are quite corroded, but they also aren’t needed anymore. Because they provide some protection, I may keep them, but if I do I’ll wire brush them and spay paint them with silver paint.

None of this actually brings me that much closer to using them as studio lights. Among other things, I need space to use them, and I also have to work out how best to position them. In the meantime, I have some painting projects I need to finish, and the lights will be really good for that—bright, won’t shift the appearance of the colour of the paint, it will be dramatically cooler, and will consume only about 24 watts of power, as opposed to the 1000 watts it used to. And, have I mentioned how dramatically cooler they’ll be?

As it was, the old worklights were pretty useless to me. Their halogen bulbs were no longer working, but when they were they were far too hot and far too power-hungry. By spending $44 I solved all those problems. It gave new life to something that would have otherwise gone to the rubbish tip, and it cost less than a modern replacement would have.

I love it when a plan comes together. Now, I just have to figure out how best to use them for photo and video lighting. That'll be a different plan to talk about.

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