Custom white balance setting

Custom white balance (CWB) setting for correct gray balance in the camera is a very powerful tool when being used correctly.

The problem is that white isn't always white when it comes to spectrophotometric definition. "Point the camera at a white surface and set CWB" just isn't enough for a photographer who wants to get it right. The problem is illustrated in the picture below.

There are three different white surfaces in the picture. From left to right: An old slightly yellowish backside of a Kodak 18% gray card. The white patch on QPcard 101. An envelope from the mail.

The camera always assumes the surface it is being pointed at when setting CWB is neutral. By pointing the camera at the left "white" surface, the whole picture becomes bluish. Many white papers are bluish, like the envelope to the right, which gives a warm tint to the picture.

In order to set CWB correctly it is necessary to point the camera at a perfectly neutral surface, like QPcard 101.

The numbers in the picture are L*a*b values measured in Adobe Photoshop. "L" is lightness, "a" is red or green, "b" is yellow or blue. 0 (zero) for a and b means neutral, with no tint of any color.

Gray balancing QPcard 101

Instruction for gray balancing with QPcard 101 using the Eyedropper tool in Adobe Photoshop.

1) Place QPcard 101 in the subject. Make sure it is lit by the same light as the main part of the subject.

2) Take a picture with white balance on camera on an appropiate setting (NOT Auto White Balance!).

3) Take the rest of the pictures without QPcard 101.

4) Open the first picture in Adobe Photoshop or other suitable image or camera software.

5) Choose the eyedropper tool and set Sample Size to 5 by 5 Average.


6) Check the gray balance in the gray patch of QPcard 101. In this example it is too blue and a little bit too green.

7) Choose Levels and click on the gray eyedropper. Make shure it isset to neutral by double clicking and checking RGB numbers. Default setting is 128, 128, 128.


8) Now click on the gray patch of QPcard 101. The RGB values will become equal, meaning neutral gray. If the gray patch still seems to have a color cast you have to calibrate your monitor.

9) Save the gray balancing profile by clicking "Save...".

10) Open the other pictures taken in the same light and same white balance setting on camera.

11) Choose Levels and click "Load..." to apply the saved gray balancing profile.

QPcard 201 x 2

QPcard 201 is a reference card with 27 different colors.

It is designed to be used with the software QPcolorsoft 501 that can be downloaded free on this site. The colors on the card are mixed separately from pigments and extremely fade resistant. Some of the colors are mixed to resemble the spectral response of colors in real life: Light skin (#18), Dark skin (#17), Sky blue (#25) and Forrest (#15). The seven neutral patches (#4?10) all have an almost straight spectral response. In practice this means the QPcard 201 can be used in almost any light condition with almost any camera, without suffering from metamerism.

The card is self-adhesive making it perfect to place on almost any surface in the subject. The size of the card is 142 x 40 mm (5.6 x 1.6 inch).

QPcard RAW package

Calibrate your digital camera for RAW shooting using QPcard 201, Adobe Photoshop and Adobe Camera RAW (ACR).

In ACR there is a tab called "Calibrate". Here you will find sliders for adjustment of Shadow Tint, Red, Green and Blue Hue and Saturation. Using these sliders you can finetune the color reproduction of Adobe Camera RAW converter. However, it is almost impossible to succeed without a reference color target like the QPcard 201.

Finetuning of RAW can be achieved manually or automatically. The manual procedure is described by Bruce Fraser here http://www.creativepro.com/story/feature/21351-1.html

In order to accomplish this with QPcard 201 you need a reference image with RGB values. This image can be downloaded here.

But there is also an automatic way to go. Rags Gardner at http://www.rags-int-inc.com has a Technology department on his site: http://www.rags-int-inc.com/PhotoTechStuff/ with lots of useful information and solutions for digital photographers. Rags has written a Javascript for automatic color calibration with ACR. The script can be downloaded free from Rags site here:
http://www.rags-int-inc.com/PhotoTechStuff/ColorCalibration/

You can read Rags explanation here:
http://www.rags-int-inc.com/PhotoTechStuff/AcrCalibration/

QPcard 101 v2 x 3

QPcard 101 is a reference card targeted for professional photographers

Qpcard 101 v2 is the new improved version of Qpcard 101. It has three patches with perfectly neutral dark gray, mid gray and white colors. The Cie L*a*b values are 35*0*0, 48*0*0 and 95*0*0. The spectral respons of the three colors is almost perfect straight, meaning there will be no problems with metamerism at all. The colors are extremely fade resistant. The main purpose with the card is to use the gray patch for neutral gray balancing of the image. The gray patch is reflecting 18 % of the light, making it useful also for exposure purposes. Since the white patch is free from fluorescent whitening agents, it is perfect for custom white balance setting of your camera before shooting. There is a millimeter reference scale on the card.

The card is self-adhesive making it perfect to place on almost any surface in the subject. The size of the card is 142 x 40 mm.