Photo Gray Cards, Color Correct Photos and Monitors

The first part of this Tip is about taking photos in a room with different lights. The second part is using this info to take photos of your paintings.

What is as Gray Card? It is a reference card with a specific neutral color that cameras and photo software use to color correct photos. The standard color is “18% gray”. The cards come in many sizes and materials. Your local photo shop will sell them.

Why and when to use a Gray Card: You want to use a gray card so the colors in your photo are as close as possible to your subject. Have you ever noticed that the President’s podium is gray??? All the cameras in the room use this gray podium to color correct for the lights!

Things that can affect the color in your photo.
If you take a photo with natural light you would expect to have perfect light. Well what happens when you are next to a green house? You will get reflected light? What if you have two different types of lights in your room? What if your subject is wearing a blue dress, or the color of your painting is mostly red. These things can confuse the Auto White Balance of your camera.

Taking your photo and Use the reference to correct the color.

  1. Take the photo with a photo gray card as a reference. Take a test photo of the card or your subject holding the card somewhere in the light the photos will be shot. This first shot will be used as reference to correct the rest of the photos when you get home. This reference photo assumes the rest of the shots are in the same light and the subject’s cloth’s colors don’t change much. Example, the color on the subject will change if they move nearer natural light or away or a million other factors.
    1. If your camera is on the default, auto settings the camera will be set to AWB, Auto White Balance. The camera will try to keep the color correct. This means even though you took a reference photo, the camera’s color balance will change. It is trying to adjust the color as best it can.
    2. In most cameras, there are some presets in the White Balance settings, see your manual. There are settings like: full sun, shade, cloudy, florescent light, incandescent light, etc. You could use these settings and get closer than using AWB as you photograph in this lighting. But if you want to be closer use a Gray Card. If you forget to change these settings back to AWB and go from florescent lights to outdoor light, your color will be wrong….
    3. To get closer yet, you need to change your camera to Custom White Balance, CWB. Read your manual. This means taking it off the auto mode!!! You are stepping into scary territory. Take a reference photo of just the card (full frame) in the room’s light and set your camera to use that as reference. Now it won’t change if someone with a blue dress is in the photo or the next shot is of a red shirt.  If you forget to change it back and you go out in the sunshine, you will have problems. I said scary.
  1. Use the gray card in the photo to set your software to the correct color. Without that reference it is nearly impossible to set correct color balance. Digital software has different ways to correct color balance. Search YouTube for “your software and correct color balance”. This is a bit in the weeds for most but you will use that reference photo you took with the gray card. Use your software to color correct that photo and use those color corrected settings for the rest of the photos in the same light.

Taking photos of your Paintings.  Do a search on “Photographing artwork” The intent of this article is to use a gray card so you can take a photo of your artwork and it match your artwork!!  How to take quality photos of your paintings needs to be covered more later.

BUT, I will tell you this now.
Use the same information above. If you are taking a photo of only one painting, use the AWB setting, but include along side of the painting part of a gray card in each shot you take. You don’t need to see much of the gray card.  Photographing art work is a bit easier in that the light in one photo will be the same in the next. Including part of the gray card in each original photo will allow you to always have that reference. So make a copy of the original. Always keep an original without any edits. In the future you may find better ways or better software to edit this image and want an untouched image.  (You can rename original from  IMG 4603 to “MonaLisaOriginal.jpg” if you want, But that is it!). Now copy that image and rename it. Don’t make changes and then rename it. You might forget and overwrite the original…. Call it “MonaLisa edited.jpg” and then make changes. Now crop the photo to actual size so you can print it but rename the cropped photo “MonaLisa cropped 11×14.jpg”.

If I am going to photograph several paintings I will start by zooming in on my 8”x10” Gray Card (full frame), then set that image as the custom white balance photo. See your manual. This sets the color correction to whatever lights you are using. It will make the following photos as good as they can be. BUT I still, ALWAYS include a piece of the gray card off to the edge of my photo. Just stick it there and when you compose your shot just include a bit of the gray card. Remember; keep the original uncropped photo with the reference gray in it.

Side tip. I often take photos of my work in progress. When I do I will put a little gray card in each shot so no matter what light I am in I can accurately adjust the color balance in Photoshop.

Glare on your paintings. Unfortunately you will get some glare on your paintings. Especially if you use your on-camera flash. If you do oil or some textured painting it will be worse. There is a way to eliminate that.   I plan on doing another article like this on using the camera flash and two polarizing filters. If interested now! Do a search on (photographing artwork polarized light) and you will find out lots of information on that subject. It is a technique that eliminates glare.  Works great but there is a bit more to it.

Gray cards are sold where cameras are sold. Ask for or search for Photo Gray Card or 18% Gray Card or color balance photo gray cards.  I have cut an 8″x10″ card into 16 pieces. Now I have little cards that I keep with my cameras and near my paintings or I can give away!

Calibrating your monitor or is your white balance off on the camera? 
Does the photo I took of my painting have correct color? Is my monitor correct? Is the photo lab printing accurate color? For sample reference images, do a search for “photo reference test page” and download a few of these images with people on them.
In short you want to check and correct your monitor to a standard reference image. With your monitor looking good check the color of the photo you took against your actual painting. If it is off it is your “white balance”.

– Open the downloaded reference photo on your monitor. Check or change your monitor to make your downloaded photo’s, skin tone, colors, and white to look visually perfect (you should be able to adjust your monitor).
– Open up the photo of your painting on the same (now calibrated) screen with one of these reference photos. Do a split screen on the same monitor (not one on a laptop and one on your desktop).
– Look at your painting in your hand and on the screen and the reference photo all at the same time. How do they look?
– You need white light on your painting in your hand, not some incandescent warm light bulb on your desk. Don’t adjust the monitor to your painting!!! If your painting doesn’t look like your monitor your camera white balance could be off.
If you ask at First Photo they use to give you a reference photo with their logo on it.

Last edited 10 Apr 19, added this last bit on color monitors and prints from labs. 2 Apr 17, Added more on making copies of original images