Photographing wall art involves three critical goals:
- Even lighting
- Faithful color
- No distortion
While an artist publishing work for magazines and high-volume prints should go to a company dedicated to making reproductions, you can go far with a DSLR and a couple of strobes, as well as a couple of other affordable tools.
Light needs to spread evenly over the entire surface of the artwork, so you need a large light source. The light from that source also has to come from the sides of the artwork to avoid reflecting any light into your camera lens.
I found that a good way to do this is to put large reflectors on either side of the artwork, and large sheets of foam core do nicely. Then point one strobe on each side of your camera with their light crossing in front of the camera to land on the opposite reflector. You need to flag the strobes so they don’t light the artwork directly — their light should only touch the reflectors.
In the video below, instead of crossing the light, I simply pointed each at the reflector on its own side. After making the video, I found that crossing the light made it easier to make the light on the artwork even.
Faithful color is more critical here than with any other kind of photography, so you need the right tools. The best tool for this job is the X-Rite ColorCheck Passport. This combination of a color card, gray card, and software creates a color profile for each lighting situation.
First, you need to get the in-camera white point set properly. Set up all your lighting, then open the Passport to the gray card and place it where your artwork is. Take a shot of the card close-up with all your lighting turned on, then use your camera’s custom white point based on this photo.
Next, flip open the Passport’s color panels and place it where your artwork is again. The X-Rite software finds the Passport in your photo, but you have to set it up so that the panel with the three rows of gray is on top like in the picture. The software might not be able to find the Passport in your photo if it sits in a different orientation.
Now you can continue with the rest of the shoot. Since lighting shouldn’t be changing during a shoot of artwork, this one shot of the Passport should do ya. You only need to reshoot the passport when lighting conditions change.
The ColorChecker Passport software includes both a stand-alone app as well as a Lightroom plugin. As I use Lightroom, I’ll describe the plugin here.
Once you copy all your photos — including the one of the Passport — into Lightroom, edit the Passport photo. First, set the white point to neutral by clicking the gray square with a notch in the second row of the upper panel. It should already be pretty close because of the custom white balance you set in camera, but this just sets it to perfect. Then export this photo with the ColorChecker Passport export preset. This doesn’t really export the file — it sends the image to the Passport software to find the Passport in the photo and create a color profile based on it. It immediately asks for a name for this profile, so name it something identifiable for this shoot.
The Passport software alerts you when the processing is done. Lightroom presets can’t tell Lightroom a new color profile exists (at least in Lightroom 3), so you have to quit Lightroom and relaunch it. You then go to the Camera Calibration panel at the bottom of the development panel, then go to the Profile pop-up menu. Choose the profile you just named. You should immediately see the colors of your image shift a bit, especially blue.
Now you need to make the darks and lights of your photo of the artwork match the darks and lights of the original artwork. To begin this process, look at the bottom row of the upper panel of the Passport for the row of gray chips. The left-most is a reference black and the right-most is a reference white. These two chips have to go to the ends of your exposure histogram.
Begin by turning on highlight clipping in Lightroom. You do this by clicking on the two triangles in the upper corners of your histogram.
Now any blacks in your image that are pure black turn blue, and any whites that are pure white turn red. Your task is to adjust your Exposure and Blacks settings to put these two chips right on the edge of purity without crossing into it. Move the exposure slider to the right (most likely, unless you over-exposed the photo) until the right-most chip turns red, then back off until it’s white again. Do the same with the Black slider until the left-most chip turns blue, then back off until it’s black again. If you think the resulting image has too much contrast, you can simply back off the Exposure and Black sliders a bit more.
You can now copy the White Balance, Basic Tone, and Calibration settings from this photo to all the other photos in your shoot by selecting all the photos in your shoot, and making this Passport photo the most selected. Then click the Sync Settings button at the bottom to copy the now-calibrated color settings to all the photos in the shoot. You only need to click the White Balance, Basic Tone, and Calibration check boxes.
Your image of the artwork now has colors faithful to the original.
Lastly, you need to go to the image of the entire artwork that just received the proper color calibration to fix up any distortion, either from the lens, from you not shooting the image from exactly directly in front of it, and maybe from the sides of the artwork not having exact right angles (you may or may not want to correct this last one).
In Lightroom’s Develop module, scroll down nearly to the bottom to the Lens Correction panel. First, turn on automatic correction which automatic barrel distortion. Click the Profile tab, then check the Enable Profile Correction checkbox. If the lens you used is in the Lightroom lens database, it’ll automatically correct the lens distortion the proper amount.
You then need to correct the edges of the artwork so that they’re square (unless they aren’t square in the original; in that case, you may want to place a frame known to have square corners that completely surrounds the artwork when you photographed it, then correct the image using that frame). Click the Manual tab of the Lens Correction panel. You then need to manipulate the Vertical, Horizontal, and Rotate sliders until the edges of the artwork line up with the grid that appears over the image. Each slider affects the other settings, so you’ll need to keep adjusting each one and correcting what each one does to the other settings until your artwork appears exactly square.
Now you have a photo of the artwork ready for reproduction. You may want to produce two versions of the photo cropped differently — one that crops to the very edges of the artwork, and one that includes the Passport. That lets people receiving that image do their own color calibration.
Many thanks to X-Rite for talking about this blog post on their blog!