Lightbrush, Painting with Light
Lightbrush is some very unique illumination technique. Instead of using flashlight or available light we work with very long exposure times in total darkness and bring the light exactly there where we want it to be. We use a torch (flashlight for the Americans) or pocket lamp to illuminate the motif for several seconds. We can move the light cone along the motif or illuminate it from different angles. We can set light spots here and there to highlight only certain parts of the scene. Etcetera etcetera. All the individual illuminations will add to the sum of the total image.
Some parts of the image will get brighter than others. It gets brighter where you rest the light cone for a longer time or move it slowly. The light gets brighter as closer you get with your torch.
Give it a try and be patient. With time you will develop a good understanding for the light and a feeling of how to move the torch along the scene in order to get the image you want.
1. Set the scene
2. Focus the lens
3. Turn the light off
4. Open the shutter (details below)
5. Turn on the torch light
6. Do the light bush stuff
7. Turn off the torch light
8. Close the shutter.
You have to mount the camera on a tripod. Use a properly stable one. You don’t want the camera to shake at all during this rather long exposure time. Unfortunately stable tripods are rather heavy and rather expensive. The same applies to the tripod’s head.
Release the shutter with some remote control. I use a cable release. You may, however, use some tethering via an app or notebook or similar but the light of the screen may disturb your light settings. An infrared release would work but cable releases are not too expensive. You must be able to lock the shutter in open state with our remote control.
On the contrary, you don’t necessarily need all the space that flashlight gear will occupy. But you need enough space to move safely around in total darkness. And, naturally, you must be able to put the room into total darkness. (If you cannot blind the windows, then you may use the night in less urban areas.)
Do not worry if you can still see a bit of light sneaking in below the door or at night though the open window. Give it a try. Shoot your scene with the same settings as for an exposure, say ISO 100/21°, f/11 for 30s, and see what you get. When the result is just black then you are fine.
Wooden floors and similar can be tricky. You will want to move around and while doing so on wood you will most certainly move the tripod with the camera on top. Concrete and tiles are safer grounds in this case. Otherwise you must not move yourself during the exposure. (Walking around is still save before the first turning on of the torch and after the last turning off.)
I did experience this when I had dimmed lights and therefore long exposures for some tabletops but I’d rather don’t want that for lightbrushes.
The making-of on the right is taken during some workshop in a studio. Most of my lightbrush tabletops where done in my lumber-room at home.
Set the camera to M (manual) and the time to bulb (bulb is next beyond 30 seconds). If your camera has a B mode, then use the B (bulb) mode. That is the same as M with bulb.
Use ISO 50/18°, 100/21° or 200/24° or whatever the lowest regular setting is that your camera provides. All my examples refer to ISO 100/21°.
Turn off the Auto-ISO if you have it. Better turn off any D-Lighting, D+, HTP (highlight tone priority) or whatever your camera provides to bring “light” into underexposed parts of the image. Now you are in control of the light and you want it dark. Don’t allow the camera to mess it up.
Start with aperture f/11. If the result is too bright or to dark, then you have several options to correct it. Open the aperture for brighter results (f/5.6 or so) or close it for darker results (f/16 or so). Move the torch and its light cone more slowly for brighter results or faster for darker pictures. You may get closer to the motif with the torch to get it brighter on the spot but then you will illuminate a much smaller strip of the scene as the diameter of the cone is smaller the closer you get. (and vice versa)
I say just give it a try.
No need for shutter release. It does not harm neither but I tend to get confused whether I am currently in pre-shutter release state (sorry, I don’t know that expression in English) or wether the shutter is currently open.
Expect total exposure times between 10 seconds and several minutes. It is your creative job that counts here. Just stop the exposure after you finished the brushing job.
Prepare your set with lights on, focus as you would do for any tabletop photograph. Use autofocus if you want but don’t forget to disable the AF afterwards.
During the whole process don’t touch the focus unless you feel that you should correct it.
Setting the light
In principle there is no difference in setting the light as for any other photograph. Light is light and it follows its physics and you cannot do anything about that. The light does not care whether it comes from a flash or a torch.
The key difference is that you do not provide all the light at once as you would with flashes or AL (available light) but you do it consecutively or even one after the other.
You may think now “Yes, but the light from such a small source will make quite hard contrast and shadows”. That is right. We could use soft boxes etc. to form the light as we would do it with flash light, but we do not need to do that. By moving the torch permanently you will create the same result as if the light comes from a soft box of a form that corresponds to your movement of the torch. We use the time dimension creatively.
You may even turn off the torch and move it and start lighting again form a different angle. That will have the same effect as using two or more sources of light in classic sets.
Have a look to my example “Adventslieder”. I started with giving light from some distance for some time to create the rather dark basic brightness of the overall image and then I moved the torch slowly closer to the headline. Doing so I created this radial gradient, the effect that the title and its surroundings is much brighter than the rest of the image.
The example with the garlic demonstrates how different various angles are. On the left one the torch was on the left high above the camera for some while. On the right one the light came from behind (against camera direction) from left and from light, one after the other.
Cone of Light
Have a look for an old torch with some classic light bulb, that can be focussed well and produces a nice and smooth projection. As torches with light bulbs are nearly extinct, this may be difficult to find.
Don’t worry. I’ve got some nice DIY workaround for you. Just use some tube. A tube with an inner diameter just larger than the torch will do. For small torches the inner code of a uses roll of kitchen paper is just perfect. If you create your own tube then use black cardboard that you get cheap from the stationary shop next door. An inner black surface will build some even more distinct cone than my example with a mailing tube that is white within.
Attach some string to the back of the torch and let the torch slip though the tube. The deeper the top of the torch is within the tube the narrower the cone of light will be. Have a look at these samples.
Types of Light
You have got a choice between two types of light, basically, when taking about torches. These days LEDs are all over the place. However for photographic applications regular old fashioned light bulbs or halogen bulbs emit far better light, especially when used along with food or any living creature (portrait).
The reason is that due to the smooth continuos spectrum of light that classic bulbs emit you can easily apply some white balance and get nice (tasty and healthy) looking colours. This is nearly impossible with cheap LEDs.
In general there are LEDs on the market that are suitable for food photography including food. However, those are rather expensive and hardly build into some torch.
You may want to give it a try just because you don’t have anything suitable but an LED torch. Do so. Everything described in this article will work out nicely but the colours. Just go for black & white instead or use dead materials, any non-food products or toys or something alike.
Background is some psychology which I cannot explain in detail. However, we humans are sort of trained on recognising minimal variances in the colour of human skins, eyes, lips, hair etc, and in the colours of any kind of food. We need that as an indication weather food is fresh and tasty and whether our counterpart is in healthy condition. That is why colour accuracy is more important for portraits and food than for any other stuff.
Frankly, I did cheat with my christmas style stills where I used candles as part of the scene.
The issue is that a candle produces much more light in total, because it does not move over the long exposure times as the cone of the torch does. This will result in the flame of the candle burning out and creating some halo around the flame.
This is how I cheated:
First I arranged the set as usual. Then I did light the candle and waited some minutes for the candle to burn down a bit and look fresh but used. Then I blew it out and made my light brush. I did photograph the light brush first because typically I do re-arrange things before I get the final shot.
Doing so I avoid illuminating the topmost part of the candles. That comes later. In these shots they appear just dead and heavily underexposed. The lower part of the shaft, however, should look fine.
Once the final shot is caught, I light the candle again and take some bracketing from about half a second to two or four seconds, depending on the aperture used before, which I do not change.
Back on the desk I hope that the tripod was really stable so that the picture with the flames perfectly matches the light brush. Otherwise I have to align them a bit. However, use your preferred image processing tool that does support layers and layer masks, although you don’t need the mask in the best case. Just use “lighten only” or “addition” as layer mode of the topmost layer and you should see your light bush image along with lighting candles.
Difference to Light Painting
Light Painting is a similar technique. Light painters usually move the source of light (torches, LED panels, Strings with LEDs, burning iron wool, etc.) within the image so that the light creates some trace, similar to the traces of lights of cars in long exposure images of roads.
So, ... Get a torch and get started!