Lesson 4 Bonus Mixed Lighting

Charlie Borland's Lighting for Commercial Photography All photos and text © Charlie Borland, all rights reserved worldwide. No form of reproduction or usage - including copying, Page 1 Lesson #3: Mixed Lighting As you begin to photograph on location, you will at some point be asked to shoot in a location that has mixed lighting. You will be challenged because you will be mixing your daylight balanced strobes with a variety of light sources that are not daylight balanced. We are not talking about shooting in a studio or going into a companies conference room to take staff portraits against a background where your strobes are the only lighting you use. Rather we are talking about locations in which you may have your strobes, window light, and fluorescents in the same photo. Your assignment is to take a portrait of the man- ager of a grocery store, and you don’t own enough strobes to light the whole store. So you are forced to use strobe and ambient light together by mixing light sources. Sometimes these mixed light sources Board of Directors are subtle and other times they are extreme. Copyright © 2006 Charlie Borland This lesson is about needing to use strobes and ambient light, often different colors, to achieve the de- sired result in your photograph. Be patient with this lesson as the theory can be complex at first, but really is quite simple. Also, we will discuss color theory and it’s use with film first, then visit digital and how to use White Balance to achieve the same results. Ambient light sources could include lights that are tungsten, sodium or mercury vapor, fluorescent, and often there is a combination of more than one of these light sources at a location. They are rated in Kelvin Color Temperature with daylight being 5500K. Tungsten at 3200K is amber, sodium vapor are very orange/red around 2100K, Metal Halide are closer to daylight. (3.1)Kelvin temperature color relationship: Amber warmer warm Daylight cool cooler blueish blue 3200K 3800K 4500K 5500K 6200k 6800 7500K 8000K There are different fluorescent lights, but the most common is Cool White. It has a Kelvin temperature around 4000K, warmer than daylight, but it also produces a green cast. Fluorescents not only need a correction for the blue/ red shift, but need filtration to bring the green part of the spectrum into line. For the sake of explaining color theory, this lesson will illustrate points as if you were shooting with daylight film. I’ll address digital white balance at the end of this lesson. We will discuss first, how to filter for ambient light before we address adding strobes to a shoot setup. The photograph on the right was taken before I set up my strobes and cor- rected for the Tungsten color shift. The digital camera set on 5500k for daylight and you can see the warm amber color shift. Charlie Borland's Lighting for Commercial Photography All photos and text © Charlie Borland, all rights reserved worldwide. No form of reproduction or usage - including copying, altering, or saving of digital image and text files - is permitted without the express written permission of Charlie Borland Page 2 (3.2)The following is a color chart of light sources and their respective Kelvin temperature. Artificial Light sources: Candle Flame 1800K Sodium Vapor 2100K 40 Watt Bulb 2600K 75 Watt Bulb 2800K 100Watt Bulb 2900K 200 Watt Bulb 3000K Tungsten 3200K Mercury Vapor 3300K Photoflood Lamp 3400K Carbon Arc 5000K H.M.I. 5500K Daylight: Sunlight, sunrise or sunset 2800-3000K Sunlight; one hour after sunrise/sunset 3200-3400K Sunlight; two hours after sunrise/before sunset 3900-4100K Direct sunlight midday 5000-5500K Overcast sky 6000-8000K I usually do not correct for these natural outdoor color temperatures as I feel they add to the photograph. Warm sunset or sunrise light makes for a great photograph. In these examples you can see how the color shifts when using daylight film in non-daylight light sources. The left image goes orange/red in Sodium Vapor and the other image goes very green in fluorescent lights. In both cases we are illustrating ambient light only, not strobe and both would require filtration on the camera to correct the color shifts for daylight film. Charlie Borland's Lighting for Commercial Photography All photos and text © Charlie Borland, all rights reserved worldwide. No form of reproduction or usage - including copying, altering, or saving of digital image and text files - is permitted without the express written permission of Charlie Borland Page 3 AN EXAMPLE: Let’s say you go into an office to photograph a person AND you know that you will be using some of the ambient light in your photo. The first thing you need to do is determine what the color balance is before you even think about setting up your strobes. You do this by using a color temperature meter and I use the Minolta color meter. Once you have determined where you will be photographing and know that you will be mixing your daylight strobes with ambient, you take a color meter reading to determine what you will be dealing with. If your reading is 4000K, that tells you that the light is warmer than daylight, remember that Tungsten is amber and rated 3200K, so 4000k is on the way to becoming Tungsten. If you took a picture now it would have a slight amber cast. The color wheel is universal in its meaning and works here just as eas- ily. If your ambient light is green you put a magenta filter, the opposite of green, on your lens to eliminate the green shift. This principal works the same no matter the color. COLOR CORRECTION (CC) FILTERS To eliminate the color cast, you need to add filtration to your camera lens to offset the color shift. I have a complete set of all Kodak Wratten Color Correction filters, aka CC filters. They come in blue, amber, green and magenta and are no small investment. The following chart (3.3) shows the relationship between the Blue and Amber CC filters and the color wheel opposites. Blue 80A is the opposite of Amber 85, they cancel each other out. An 82A is the opposite of 81B. So if you are trying to filter out blue light in a scene you add Amber to the lens and vice versa. (3.3)Color Correction (CC) Filters: Blue 80A Amber 85 80B 85C Bluish 80C Warm 81EF 80D 81D 82C 81C 82B 81B Pale 82A Pale 81A Blue 82 Amber 81 In addition to the blue/amber CC filters, you will use Magenta filtration for correcting the green shift of Cool White fluorescent light and they come in increments of .05 .10 .20 .30 .40 and .50. The most common filters used are the .30 and .40 and occasionally the .10. I do not own the .50 as I have never needed it. The color meter will tell you which filter to place in front of the lens to eliminate the color cast and you may often be required to use a combination of several different filters because your scene may have a little daylight and fluorescent mixed together. You should also try to limit the number of CC filters that you put onto the lens as the various surfaces will affect the quality of your images definition and contrast. Charlie Borland's Lighting for Commercial Photography All photos and text © Charlie Borland, all rights reserved worldwide. No form of reproduction or usage - including copying, altering, or saving of digital image and text files - is permitted without the express written permission of Charlie Borland Page 4 HOW TO USE A COLOR METER You first turn on the meter and check to make 1 sure that the meter is set to the Color balance (film or digital white balance) you are using. Here the meter is set for Daylight. You next push the side button to take a reading of the ambient light color temperature where 2 your subject will be. Here the display reads 4000K. You next push the LB Button (Light Balance). It 3 reads -67. Turn the meter over and under LB chart look for the closest to -67. -56 is closer to -67 than -81 is, so you will see next to -56 that it calls for an 80C Filter. This is the first filter that goes on 4 your lens. Its blue and it is canceling out the amber color shift . Turn the meter back over and push the CC 5 (Color Correction) button. It reads -3. Charlie Borland's Lighting for Commercial Photography All photos and text © Charlie Borland, all rights reserved worldwide. No form of reproduction or usage - including copying, altering, or saving of digital image and text files - is permitted without the express written permission of Charlie Borland Page 5 Turn the meter back over Note: again and find the –CC chart In case you are thinking, “Digital solves where is shows -3 to be be- all these problems”, the point must be tween -2 and -4. I will emphasized that mixed light is mixed choose -2 and place a .05 light and even digital cannot change that. Green gel on the lens next 6 Digital does make it easier, but this les- to the 80C. This should give son must cover the theory and the strat- a perfect color balance egy for solving color problems first and where the meter reading that will make understanding how to use was originally taken.

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