Lighting Your Art - After You Paint (22 of 27)

Lighting is a really important part of art, both when you create your work and when you display it. The lighting can change the colors and even the values that you see. If you paint under one lighting condition and then display your work under another, it can mean that the viewers won't see it as you intended. Lighting also affects the longevity of your work. How long a painting will last before showing some signs of deterioration is partially related to the kind of lighting where the piece is displayed. So it's an important topic for many reasons. It's a complicated subject really. So I'd like to begin with some fundamental work. We need to understand some of the important terms related to light such as lumens, wattage, color temperature, color rendering index, UV radiation, and more. But don't worry, don't feel overwhelmed. Although these topics may sound a little intimidating, I'll do my best to simplify each and discuss how each relates specifically to us as artists. After we learn the terminology, we can then discuss light bulbs, light fixtures, and lighting designs. I'll also offer some suggestions based on what we learned. The first term we're going to learn about is lumens, which is basically a light's brightness. It refers to how much actual light is given off by a light source. Think luminosity or the total light emitted. Direct sunlight is of course the brightest light source with a lumen level of between 30,000 to 130,000 lumens. Compare that to room lighting which for a 10x10 room is typically about a lumen. The brightness level is related to the size of the room. If you think about it, when you enter a room and it's very bright, the lights have a high lumen level. One that's dimly lit has a low lumen level. Think of the various shops or doctor's offices that you've been to. Some are dimly lit, some are moderately lit, and some are bright. For example, experts recommend 10 to 20 lumens per square foot for bathrooms, and kitchens need about 70 to 80 lumens per square foot. A home office usually needs 60 to 80. A workspace 80 to 100, a hallway which is normally dim, 5 to 10. This should give you an idea of the impact of lumens. Now, when it comes to the term wattage, you've likely already heard the term. Wattage relates to the lumens in that it's the power or the amount of energy needed to create the brightness level emitted by the light source. So, wattage is the amount of energy needed to create the lumens. If we compare two different light bulbs that emit the same brightness level, 3 to 500 lumens, a moderately bright bulb, an incandescent bulb will use 40 watts of energy to produce that light, while an LED bulb will use 3 to 5 W of energy to produce the same. Different levels of energy can produce the same brightness depending on the light source. Wattage or energy level is also related to heat output, which can be an issue when it comes to artwork. Think about the difference in heat emitted by an incandescent bulb as opposed to an LED. LED bulbs remain cool no matter how long they're lit because of their low energy use. While incandescent light bulbs gradually heat up and can get pretty hot, this may not be an issue in a large room, but if you use an incandescent bulb in a picture light that sits close to the surface of a painting, it would gradually heat the surface, and as we learned earlier, that can cause problems for certain paints. It would create a kind of microclimate that's not good for art. At a distance, however, it wouldn't have too much of an effect. So, lumens is the brightness and wattage is the energy used to create that brightness. There's also something called lux. Lux refers to how much light is reflected off of a surface or basically how bright the surface is. It's also referred to as surface illumination or light intensity. Damage to paintings from a light source is usually related to the intensity of the light or lux and the amount of time exposed to that light. A high degree of lux for a long period of time can age pigment colors, binders, and varnish. The higher the lux, the more light on the surface. And the longer that painting is exposed, the more quickly it'll age. Now, we're talking about for the most part a long period of time, but it is something to be aware of. Keep in mind that art museums recommend a lux of 50 to 200 on artwork. To give you an idea of what that level might look like, a standard living room or bedroom has a lux level of 50 to 150. A bathroom typically has 150 to 300 lux. A reading light 2 to 300 lux. and a lux of 500 is used for areas of intense work where fine detail is executed. Operating rooms have a lux of a thousand. As artists, we may prefer a brighter lux on our surface when painting or drawing, especially when working on details. Because this is short-term light exposure, it's not going to be an issue. But certain light forms aimed at artwork with a high lux for a long time might result in the fading of some pigments. Foot candle is another term you may hear for lux and it basically means the same thing. It's just a different form of measurement. Lux is the metric measurement lumens per square meter and foot candles is the imperial measurement lumens per square foot. Just for interest, one foot candle equals approximately 10 lux. Now, I'll be using the term lux in this class. So, to review, lumens is the brightness and wattage is the energy used to create that brightness. Lux is how intense the light is upon the surface. But light also has a color temperature. All light has a color temperature, meaning it leans towards a warm or a cool tone. You may have already experienced this with the growing popularity of LED bulbs, which when they first came out tended to look fairly blue as compared to an incandescent bulb. You may notice color temperature when walking by or into certain stores. Just like some stores are bright and others are dim, some stores appear cool and crisp while others appear warm and relaxing. This difference is usually the result of the color temperature of the light. Color temperature is measured in degrees Kelvin. Now this was named after a British physicist named Lord Kelvin who established a scale for measuring color temperature in the 1800s. Kelvin goes from zero, no visible light, to 1,800K or candle light, all the way up to 10,000K, which would be a clear blue sky. Typical lighting falls somewhere between 2,00 to 6,500K. The higher the number, the cooler the light. The lower the number, the warmer the light. Warm light is often used in homes because it's considered pleasant and cozy. Offices and kitchens, on the other hand, tend to use a cooler light because it conveys as clean and crisp. Cool light tends to appear brighter and often helps people stay alert, so it can be used in operating rooms and places like that. Warm light helps them relax, so it might be good for a waiting room. We renovated our laundry room a few years ago. Prior to the update, the room used incandescent lighting and had off-white walls. To me, it always seemed dingy, even when it was really clean. We painted the walls white and installed LED lights at 3000 Kelvin, and it instantly looked super clean and cheerful. It was an amazing difference. Natural daylight is said to be somewhere between 5,000 and 6500K, but this is dependent on the time of day. To my eye, natural light in the morning seems to have a cooler appearance. An evening light to me tends to look warmer. Noon looks the most neutral. So, what is considered neutral color temperature? This is important as artists. The more neutral the light, the better it is for painting and exhibiting artwork. You certainly don't want a color influence. But who determines what is considered neutral or pure white? Some experts say pure white or neutral light is 3500K. Some say 5,000K and some say 6,500K. This is probably because the human eye literally sees color differently by individual, even if slight. I give a thorough explanation of this in my understanding color class. The most common opinion though is that it's 5000K. But is that the best color to hang your artwork in? Well, interestingly, in 1995, tests were conducted at the National Gallery of Art in Washington, DC to see what lighting temperature viewers preferred when looking at various artwork. Almost unanimously, a lighting temperature of 3700 was preferred, give or take 2 or 300. Lumens and lux were factors as well, but it gives us a solid reference point. My studio lights are 3500K and I personally feel they produce a very nice color temperature. I paint under that lighting and I use it in my studio gallery as well. According to waveform lighting, 3000K appears to be the standard color temperature used in art galleries. End quote. It is recommended that you use the same color temperature throughout your room. Otherwise, it can cause the eye some confusion. Color temperature, however, isn't the only color related topic for consideration when it comes to illuminating our artwork. There's another equally important factor, and that is color accuracy. How we see color under various forms of light is dramatically affected by what we call CRI or the color rendering index. It's also sometimes called RAW. This refers to how accurate colors appear under artificial light as compared to sunlight. We see true color or 100 CRI under natural light outside in daylight or near a window in our home, especially between 10:00 a.m. and 2:00 p.m. when light is most neutral. Light produced from man-made fixtures can actually alter the accuracy of the colors we see. Now, humans are not able to discern CRI levels simply by looking at a light or when examining the color temperature of light. The only way to tell by the naked eye is to see how colors are reflected by the light source. For example, you could look at an item outside and then look at the same item under a light fixture. If the artificial light source has very good CRI, the item will appear nearly the same. Red elements are especially good for determining this. And I find that some greens are strongly affected as well. CRI values range from 0 to 100. A rating of zero refers to monochromatic light. Basically, light at night, for example. And a rating of 100 refers to natural sunlight or the light at noon. Believe it or not, incandescent lights tend to have a CRI of 100. But they also carry several negatives, including the fact that they normally have a very warm color temperature around 2700 and they emit too much heat at higher lumen levels, so they're not preferred. Let's look quickly at the typical CRI ranges per light bulb type. My studio lighting uses bulbs that are 98 to 99 CRI, which is one of the reasons it produces such a pleasing color accurate light. I've tried bulbs of the same color temperature, 3500, but with a lower CRI, and the difference was dramatic in a negative way. The whites in particular looked dingy. If I changed the amount of lumens in the light, that might help a little bit, but not enough. A CRI rating of under 80 is considered poor. A rating of 80 to 90 is considered good, although in my opinion, I don't think it's good enough. And a rating of above 90 is considered excellent color accuracy. If you can get close to 97 to 100, even over 95, that is best. So, lumens is the light's brightness. Wattage is the energy used to create that brightness. And lux is how intense the light is upon a surface. Light also has color temperature. And the accuracy of those colors is impacted by the CRI level. We also have to concern ourselves with ultraviolet rays. Now, bear with me. This all creates a foundation for our discussion on light bulbs when we get to it. I mentioned that certain lighting can be more detrimental to artwork than others. Natural daylight is one of those risky light sources because one of the most damaging aspects of light is ultraviolet light radiation or UV. And this is a natural part of the sun's rays. So although natural light has complete color accuracy, especially between 10:00 a.m. to 2, it's not good for art long term. Light bulbs tend to be safer in this respect than natural light. That said, fluorescent, halogen, incandescent, and some photography lights emit various levels of ultraviolet rays. But sometimes a UV filter can be used to reduce the impact and bring it down to safer levels. This is the case with my studio lighting. They're halogen, but they're filtered. Sadly, those forms of lighting were recently discontinued for environmental reasons, leaving us with mostly LED based light bulbs. But this could be a blessing in disguise since LED bulbs emit little to no ultraviolet light by their very nature. That makes them a potentially good option for art lighting as long as the other factors line up right. In fact, art museums around the world are slowly transitioning to LED gallery lighting as the technology continues to improve. UV radiation impacts art regardless of the painting medium. All artwork that uses colored pigments, a binder, or varnish can be impacted. However, it is somewhat dependent on the thickness of the paint layer, as well as the type of pigment used. Thin layers of paint are a little more vulnerable to fading because rays of light can penetrate the layers of the paint if it's thin and fairly transparent, which is why many consider watercolor paintings a little more at risk. And specific pigments are more vulnerable than others. Watercolor paint manufacturers have gotten more careful about their selection of pigments. Not to mention that UV glazing can block up to 90 or even 99% of the UV radiation. So if precautions are taken, the risk should be closer to that of the other mediums in my humble opinion. But believe it or not, any visible light over long periods of time can impact the color of paint. One precaution you can take is simply to turn the lights off in a room if you're not actively using it. Remember, however, that oil paintings need at least a small degree of light to prevent dark yellowing. The way I handle it is to turn my studio or gallery lights off when I'm not there, but to leave one door blind open so natural light enters the room without direct sunlight on any of my work. And I have nightlights plugged in to two of the outlets for nighttime illumination. My hanging art has not changed, as far as I can tell, for many, many years. In spite of the UV risk, natural light is the most desirable lighting when you're painting. And it's a great option as long as it's not direct sun. Northern facing windows are historically the artist's ideal light as it provides bright neutral indirect light throughout the day. But light from an eastfacing window is also considered pretty good for displaying your finished work. Indirect UV filtered natural light also seems to be acceptable for ambient lighting in a room. normal household window exposure that's indirect. Window panes can be UV filtering and you can also opt for UV filtering glazing when you frame. Still, artificial light that meets the specifications listed previously might be the safest way to go and there are many very good options out there thanks to technology. Next, let's take a closer look at the different types of light bulbs and how they relate to what we've learned so far. [Music]