Lighting 103: Use Gels to Tune Your Home's Lighting

Abstract: You can use your knowledge of color temperature and gels to improve the quality of light in your home.



So far, everything we have done has centered on gelling a single light to create a single desired color shift. But before we make the jump into using multiple colors and light sources, one quick hack for your home's lighting that will help you to improve the quality of light in compact fluorescent and LED bulbs.

Like the gawdawful green-tinged lamp above, for example.
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We're pretty eco-friendly in our home, with photovoltaic solar panels, passive solar hot water and (mostly) LED bulbs throughout the house. The latter have gotten very cheap, and are a great way to save energy and money.

But many LED bulbs have pretty bad color rendering index (CRI) ratings, and can be all over the map on the Kelvin scale. And by that I mean not just warm or cool, but garish side trips into green as well.

As photographers who now understand that color is a very fungible quality, can't we fix that? Of course we can.


How to Cheaply Improve Your Home's Lighting

First off, as a lighting photographer, have you taken a moment to think about the continuous lighting you use in your own home? If not, why not?

You can using lighting to redefine a room without spending a lot of money. (If you live near an Ikea, this is especially true.) The biggest lighting problem with many rooms—especially bedrooms—is that the main switched light is usually directly overhead in the ceiling. You can improve the quality of light with a big, soft fixture overhead. But a bedroom, for instance, really benefits from multiple soft light sources positioned lower in a room.

Some rooms feature switched outlets, where the top plug in each dual outlet is controlled by a switch and the bottom one is on constantly. This is a decision made by the electriction when s/he initially wires the room, and it is expensive to change after the fact.



Fortunately you can buy remote switches for non-switched outlets very cheaply now. With the kit above you can independently control up to five outlets in a room with one of two included remotes for $30. So if your bedroom (or living room) is still being lit with a bright overhead light, there is no reason you can't cheaply change it.

I switched out our master bedroom and it made a huge difference in the feel of the room. We opted for a triangle of soft light sources. In an instant, the room was transformed from what was basically police interrogation lighting into a soft, relaxing glow.

And it wasn't even expensive. I chose two $13 table lamps and a $20 floor lamp, all from IKEA.

Since our outlets were already switched, we were out the door for about $50—even after we added the LED bulbs. If we had non-switched outlets and needed remotes, our total cost would still have been well under $100.

But while the softness and distrubution of the light looked great, the color was pretty bad.


Let's Improve the Color



Here's the lamp again, untweaked. For the record, this is shot at 3200K (incandescent) white balance, and is straight out of the camera. It's underexposed a little to better show the inherent color shift. In the room, my eye perceives it as a gharish yellow-green tinge.

So where do we start? What are the components that could be improved?

First, it's too warm. This is because the "warm daylight" (what they call 2700-3200K LEDs and CFLs these day) bulb is also going through a warm rice paper lamp shade and bouncing off of a wall that is somewhere between dark cream and light taupe. Both of those things exacerbate the warmth of the light.

Second, and worse, there is a green spike in the color spectrum of the cheap LED. And I absolutely hate that. That green tinge is not exactly going to help me relax at the end of the day. In fact, I'd go as far as to call it headache-inducing.

But color ain't nothing but a number. So let's fix both of those things.

First, the warmth. It's an incandescent-colored bulb, going through a craft-paper-colored shade in a warm environment. To the eye, super warm. I want some warmth, just not that much. So let's try a 1/2 CTB sheath for the bulb, which we'll make out of some scrap gel.

And how do we offset the green? With magenta. So to the 1/2 CTB, I'll add a weak magenta, too. Call it a CalColor 15 Magenta.

Here's what it looks like:



It's a tube, with a printer paper topper. (More in that in a minute.) And yeah, the magenta is smaller than the CTB. I only had small pieces of it to work with. But it turned out to be fine.

Here it is on the lamp, without the shade:



A few things to note here. First, safety. This is a low-wattage LED bulb. It barely gets warm. You can sheath it in gel and it still won't get very hot. Use more gel to add air space for venting if you have brighter lights. And please do not do this with incandescent bulbs. (Likely not needed anyway, as incandescents have a gorgeous CRI as they hurtle us all toward climate change oblivian. Yee haa!)

Second, the sheath does not normally ride this low because the arms of the shade (when installed) hold it up a little higher. So the paper top does not normally droop on the bulb like that.

Finally, the paper top. It was added to diffuse the light coming out of the open top of the lamp, to kill the shadow pattern cast by the shade arms. Because that's how I roll.



Here is the result. And for the record, I adjusted the exposure to account for the (~1/2 stop) light loss. So it is apples to apples and straight out of the camera.

Here they are side by side:



And to be clear: This is the lamp tuned to my in-person preference, not that of the camera. The camera sees it a little differently—I can see a little green left in the photo, where I perceive none with my eye in person. But I wanted the photos to be both straight out of camera, and with no Photoshop corrections, just on principle.

The excess yellow/warmth is better. I could make it even cooler—I haven't decided yet. That would just mean upping to a 3/4 or full CTB. More important, the headache-inducing green spike is gone. The amount of warmth is negotiable for me. The green is a deal-breaker.

All in all, a much better quality of light from a $13 lamp and a $2 LED bulb.

And the room is greatly improved by the changed/tweaked lights, all due to a little working knowledge about light location, quality, and color temperature.

HOMEWORK:

Train yourself to pay more attention to the quality of light in commercial spaces—especially higher end retail, hotels and/or lounges. In many cases it was created by a professional lighting designer.

How do you react to the light? Does it relax you? Is it flattering? Does it make you want to order a $15 drink?

How could you apply what you learn to improve the lighting in yuour own house? For instance, are you using overhead fixtures? Even if you are also using nightstand lamp(s), do you rely on the overhead light for the heavy lifting?

What would the quality of light be if it were distributed around the room by lower, softer light sources? Maybe steal some table lamps from around the house and experiment without spending any money.

Is the color of light coming from the lamp(s) ideal? If not, how would you change it? Would it require a simple warm/cool color shift, or is there a second color axis that needs to be fixed?

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FOOTNOTE: Yes, I know there are now inexpensive RGB LED lights that are color-changeable via credit card-sized remote. But for nautral/tungsten colors, they are way worse than the cheap, single-color LED lamps.

And yes, Philips Hue bulbs (and the like) will allow me to alter color with more control—but at a price. For me, gelling inexpensive bulbs is a great solution for light quality and price.


COMING NEXT: Greg Heisler on Light and Color