The Photos of My Drawings Are Too Dark
A very common problem I see with photographs of drawings on white paper is that they’re underexposed, which is another way of saying they’re too dark. The cause of this is the white background fools the exposure meter.
The average snapshot consists of a variety of values. An outdoor photograph usually consists of a bright sky, a few dark shadows and some midtones such as Green grass. All of those values would average out to a light gray. That’s why the light meter is programmed to expose for a scene that will average out to a value of 18% gray.
This works out well for most general purpose photography. It fails miserably though when the subject is predominately dark or light.
When photographing a predominately light subject, set the exposure so that the meter says it’s overexposed by one or two stops. All cameras have an option for increasing or decreasing the brightness. Increase it until the image appears brighter. If you shoot in manual mode, you can use a gray card to obtain a precise exposure reading.
While the meter may say it’s an overexposure, it’s technically a proper exposure. The reason why the light meter is providing inaccurate readings is because it’s expecting a typical scene to average out to 18% gray. So when you point the camera at a White surface it gives you the settings that will make it turn out as a light gray.
The Exposure Meter Experiment
Below is an experiment where I set my camera to automatic. I then took a picture of a White sheet of paper and then a Black sheet of paper. The result was they came out as very similar shades of gray.
Why would a white sheet of paper appear nearly identical to a black sheet of paper when photographed using automatic exposure?
In the first experiment, I pointed the camera at a white piece of paper and the light meter assumed that the scene should have a value that is equivalent to 18% gray and it used the setting that will achieve that. It made it darker until it was a light gray.
In the second experiment, the light meter it made the same assumption that the scene would average out to 18% gray. It then used the settings that would lighten it so that it would match a light gray.
This experiment explains why photographs of white objects are often underexposed (too dark). The bright white surface of the paper fools the light meter. It sees the brightness of the white paper and thinks that it needs to reduce the exposure.
A simple solution for photographing pure white objects is to manually adjust the exposure until the meter reads that it’s being overexposed by +1 to +2 stops. You may already do this through trial and error by looking at the results on the LCD, and then adjusting it so that it appears lighter. If you’re photographing a dark painting you would do the opposite, adjust the exposure so that it reads that it’s being exposed by -1 or -2.
Using a Gray Card to Determine the Exposure
A more precise way to take an exposure reading is to give the camera exactly the type of scene that it’s expecting. A gray card has a surface that equals 18% neutral gray and are available at camera stores or online.
To use the gray card place the card in front of the painting, and manually adjust the exposure. In this case you will place it in front of the white piece of paper. Then you can remove the card and take the picture. It’s important to have the camera set to manual so that the camera doesn’t automatically adjust the exposure when you take the card away.
Another important point is that you just want to use the exposure meter to read only the card and not the surrounding areas. There are two ways to accomplish this. The first method is to set the metering method to “spot metering” so that it determines the exposure by measuring just a small spot typically located in the center of the viewfinder. Fill up this spot with the gray card and take a reading.
Below are the same white and black paper experiments but this time I used a gray card to determine the exposure. I framed it in the viewfinder so that it filled up the entire picture and then adjusted the exposure manually so that it used what the meter was suggesting was a proper exposure. It was taken at f/5.6 at 1/8 of a second. Then, I remove the gray card to reveal the white sheet of paper and take the picture, even though the exposure meter is indicating it’s an overexposure.
Again, this won’t work if you have the exposure mode set to an automatic setting because the camera will automatically make adjustments as soon as you point it at a different scene, so make sure you have it set to “M” for manual.
I then took another photograph of the Black sheet of paper without changing any of the settings. The aperture, shutter speed and ISO were identical. The exposure indicator was to the left indicating an underexposure, which I ignored. The unedited photo is on the bottom. Compare these photos to the originals.
Photographing Line Drawings
Photographing a line drawing or a predominately light image, is very similar to photographing a white piece of paper. Below is a photograph of a sketch of some boats that contains a lot of white space.
In the comparison below, the bottom photo uses the settings indicated by the light meter. Notice how it appears too dark just like the photograph of the white piece of paper in the above section.
The top photo uses the exposure settings from taking a reading from the gray card. The White of the paper is more accurate. I prefer even brighter Whites but I make those adjustments in Photoshop. The image above is the final result. If you overexpose by too much, then you will lose all of the detail in the highlights.
One last thought. If this is all too confusing and technical then just increase the exposure to make it brighter and view the results on the back of the camera. Increase it until the White of the paper looks correct. If you’re photographing a dark image, decrease the exposure until the dark areas appear as dark as you prefer.
