Un Retrato Ligero

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Okay cod-liver oil time, here is some of the lighting theory that makes this image work. Looking back at Frame One and Frame Two or Three, the source that lights your subject, called the Source of Illumination, is critical. Its relative size and its relative distance to the subject have a profound effect on the light quality we see on the subject – how hard or soft it appears. The Main Source of Illumination to Sylvianne in Frame One is the light head. The light head is also the Origin of the Source. It is where the energy originates. In Frame Two or Three notice how the light quality has changed by adding the panel. The light head is no longer lighting Sylvianne because the fabric blocks it. However, a lot of the light is still transmitting through the fabric (and is altered by it) onto Sylvianne. In this image the fabric is the main-source of illumination. It is the source that lights Sylvianne to her correct exposure value. The light head is the origin of that source. It is important to differentiate between source and origin because it is the actual source that affects how the light looks on your subject. Using a panel instead of a soft-box or umbrella makes it possible to separate the source from the origin. By separating origin from source allows you to create the effect of many lights with just one light and still control the brightness individually. For example, if you find that the background is not going to pure white, simply add another layer of fabric over the panel. In fact add as many layers as you need to drop the brightness on the subject relative to the brightness of the background, then increase your exposure with either aperture or shutter-speed (if you are not using strobe) to once again correctly expose the subject, which will result in an over-exposed background.

The background in the image of Sylvianne is a plus one (one stop brighter than middle grey) light grey seamless backdrop paper. If it were a white seamless paper or a white wall, it would have been even easier to create pure white on the background. Keep in mind that a white wall or a white seamless backdrop is not pure white, it is light grey and its actual value on the grey scale is about 2 stops brighter than middle grey or as I say a plus two grey. To push it to pure white you need to give it 1/3 to 1/2 a stop more brightness than what would render a correct exposure of that white surface. In fact the above method of cutting brightness to subject by adding more layers of fabric over the panel and then re-metering and resetting exposure on camera works so well that you can use it with even darker neutral surfaces and still achieve pure white backgrounds. In theory you could create a pure white background from a black backdrop. Think about it, if you give black enough over-exposure it too can be rendered as pure white. Something you should keep in mind is that when you add more layers of fabric to the main-light panel, the light on your subject will become warmer in colour balance (not a concern for B&W)

By the way, you can control the fall-off of light on the background to keep the background brightness even from edge to edge by angling the backdrop to the light origin (in this case the light head). If you are using a seamless backdrop paper supported with light stands, drag the side furthest from the light origin (the camera right side of the background in our example image of Sylvianne) towards the camera, and push the side closest to the light origin further away from the camera. This pulls the furthest side closer and pushes the nearer side of the backdrop further, resulting in even lighting across the backdrop. If you are using a wall or a fixed backdrop, set up your subject, lighting, and camera on an angle to the wall so that the wall is on the same angle relative to the camera as described above – the background’s furthest side from the light origin positioned closest to the camera.

When I made this image I included another panel with white nylon stretched over it to reflect stray light from the main-light panel back into the shadow side of Sylvianne. To control how bright the shadows appear you simply move the panel closer or further away from the shadow side of the subject and/or switch to silver lamé if you want an even higher return. In the end I discarded the fill panel because more than enough light was already filling in the shadows from stray light bouncing off the wall on the camera right side of the set. If I had wanted the shadows darker, I would have simply blocked this wall fill-light by placing a panel with black fabric stretched over it.

And now for even more cod-liver oil. A shadow is an area on a subject or object that receives no light whatsoever from the main source of illumination. However, it may receive some light from an extraneous ambient source (eg fill light, fill card, open sky). The shadow is always darker than the subject's or object’s true tonality. In other words it is an under-exposed area and is under-exposed because it receives no illumination whatsoever from the main-light source.

The reason that the light on Sylvianne in Frame Three is more forgiving to imperfections of the flesh compared with the light quality in Frame 1 is due to control over an area of lighting called Shadow Edge Transfer. When light from the main-light begins to see over into the shadow, this contaminated area is no longer considered shadow. This transition area between lit and unlit will be brighter than the shadow, yet darker than the fully lit area. And since, by definition, a shadow is an area of the subject that receives no illumination whatsoever from the main-light, then these borderline areas are considered to be transfer areas. All of our senses are very sensitive to rates of transfer. How much you notice a change will be dependent upon the actual rate of transfer. For instance, if you walked into a kitchen and the refrigerator was making a loud humming noise, it would draw your attention. However, your sense of hearing would acclimatize, as all our senses do, to the sound after a few minutes. If it increased in volume over the span of one second, a rapid transfer, it would immediately draw your attention. If it were to increase in volume over a period of half an hour, you probably wouldn’t notice the change at all. The same is true with vision when you are lighting. If you can take the edge of the shadow and make it transfer over a larger area, it becomes less noticeable. This is a particularly good thing to consider when lighting people. In portraiture, unlike fashion, photographer’s subjects are usually regular people. Regular people tend to have less than perfect flesh – they have bumps and wrinkles on their faces. Caucasian flesh tone is light. We see shape and form on Caucasians pre-dominantly with shadow. Wherever there is a bump or wrinkle, a shadow is formed. If you are able to make some of the main-light see around into the shadow, a softer rate of transfer will occur creating a softer edge. Soft edge transfer is part of Soft Light Quality.

A soft-edged shadow draws less attention. Creating a gradual transfer from a shadow into the main-lit area of the face helps reduce retouching in portraiture. For example, in Frame One of Sylvianne, look at the rough textured flesh on her neck on the edge of the shadow. Compare this with the same area on Frame Three of Sylvianne, the texture is less noticeable, the larger light source in Frame Three has eaten further into the shadow creating a much softer Shadow Edge Transfer than could the small light source in Frame 1.

The effect of size of source on transfer area is directly related to the dimensions of the light source. If a main-light were enlarged by four times, the main-light would see four times further into the shadow – the Shadow Edge Transfer area would then cover a four times greater area. A light source is visually two-dimensional; it is made up of height and width. You can create two different rates of transfer with one light source by choosing a light source made up of two different dimensions. A “strip-light” does exactly this; it is a small light source in one direction and a larger light source in the other. This creates softer edge transfers one-way and harder edges the opposite way. On a face, placing a 3ft by 6in strip-light vertically will create soft shadow edges up and down and hard shadow edges left to right – horizontal facial lines or wrinkles would be less noticeable than vertical ones.

This lighting set-up used on Sylvianne solves a lot of problems. It allows us to create pleasing lighting on a subject against a pure white background with minimal equipment, it reduces retouching, and it allows us to change backgrounds really fast. I still use this set-up today, originally when I was a starving disciple of Dean Collins, I would use white bed-sheets for panels, iron plumbing pipe set in an empty paint can full of concrete for stands, an inexpensive 500 watt tungsten security or work light, and 400ISO film with a long exposure (f5.6 at a 1/15th). However I must say it is a lot easier with Chimera light panels and a Whitelightning X1600 strobe head and my clients don’t think they have shown up on laundry day.

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Photo Quote: We must remember that a photograph can hold just as much as we put into it, and no one has ever approached the full possibilities of the medium. - Ansel Adams