On an artist forum my friend Neal built a neutral colored box in which he placed some items for a project he was working on. When I saw his box, the "aha!" moment came. I had a lot of 16"x20" paintings that at one point were some very sorry attempts at open studio sessions. Why not use these to create my own neutral box to photograph still lifes in?!
I painted four of them with several coats of a neutral value 5 gray. Then some small hinges were attached to the back of the stretcher bars of each canvas. With these in place the sides can be opened or closed depending on how much light is desired within the object inside the box.
So why bother making such a box?
Simply put to capture the true color of the object when taking a reference photo and to aid in finding the true values of the object while painting the set up.
There are many different light sources, such as the sun, artificial lighting, a camera flash, etc. These lights strike an object and reflect back to our eyes giving our brains information which is processed by what our brain presumes to be the "real color" of the object.
Presumption is a dangerous thing! Every light source creates subtle variations on the original color of the object. Let me prove my point. Take a piece of white paper and grab a camera. Look at the paper under florescent lighting. Probably looks like white to you, right? Take a photo and move outside under sun light. Does the paper still look white? - take another photo and move indoors and repeat the process.
Now upload your photos and take another look. You will notice that the florescent light has given the paper a slight bluish hue, the sunlight gave the paper a yellowish tint and the indoor shot depending where you stood when you took the photo most likely gave the paper yet another tint, based on the reflected light off the surrounding areas. So what happened to your white paper?
Unlike the brain that presumed the paper to be white, the camera captured the existing lighting conditions without any interpretation and reproduced exactly the color temperature of the light as it hit the object at the time you pushed the shutter.
In order to compensate for various color fluctuations, such as in the above shot reference photos, photographers often use a gray card. A gray card is simply a card that has a neutral value gray.
By taking one photo with the gray card in the shot, subsequent photos of the image can be cross referenced for color accuracy. The gray card reference shot is taken by holding the card at a straight angle next to the object and taking a photo. If you are taking portraits you can have someone hold the card, with both the card and their face visible. This should help you to determine if you got the skin tone right.
The principle for the box is the same. When photographing the set up, the gray background acts as your constant known color reference. Against this background color corrections can be made to make sure that your reference photo will be as true in color as possible.
Here are the steps I took to find the true color for the reference photo:
1. Take photo and uploaded to Photoshop
2. Image- Duplicate
3. Crop background gray only and CNTRL C
4. File - New - CNTRL V
1. Go back to original image
2. Click IMAGE - ADJUSTMENT - LEVELS
3. Click on the middle eye dropper
4. Position the eye dropper over the gray image (gray card) and click
An instant color adjustment will be made by Photoshop. Photoshop's software took the information of the gray value and made the appropriate color corrections.
But that's not all...
The idea of painting a still life is that you paint as much of it from life observation as possible. Now the neutral gray value will act as your reference against all values represented in the still life. As you squint, you can determine if the value you are looking at is lighter or darker than your mid value of the background. This should help greatly in hitting the right values right from the start and make for a stronger painting.