011H Gray Cards. Gretagmacbeth $69.00

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1 011H Gray Cards Accurate white color balance and exposure are necessary in optimizing image captures. Taking an additional capture of the scene with the gray card makes it a lot easier for a neutral color balance of the scene. The middle gray is optimized for 128R 128G 128B (Red/Green/Blue). This is an excellent check on obtaining correct exposure. There are several on the market. The original standard color checker is: Gretagmacbeth $69.00 This is a 9 x 12 calibrated color card. In hand held work the size is a little overkill. All the colors have specific numbers that can be used to determine the correct colors in a digital image for accurate color rendition. When photographing specific colors, this card is a must. Beyond the scope of this class. REG/X_Rite_MSCCC_Original_ColorChecker_Card.html X Rite Color Checker: The Original ColorChecker Card from Xrite is a checkerboard array of 24 scientifically prepared colored squares in a wide range of colors. Many of these squares represent natural objects of special interest, such as human skin, foliage and blue sky. These squares are not only the same color as their counterparts, but also reflect light the same way in all parts of the visible spectrum. Because of this unique feature, the squares will match the colors of natural objects under any illumination and with any color reproduction process. The ColorChecker provides a totally non-subjective standard of comparison to help determine the true color balance of any color rendition system, and it provides the needed standard for comparing, measuring and analyzing differences in color reproduction in various processes, thereby avoiding costly mistakes. specs from B and H 1

2 X Rite Color Checker Passport $99.00 This is a pocket version of the Macbeth color checker. It can be purchased as is or with software that can profile your images with all 24 colors. Being pocket size, it is easy to carry around and handhold in the scene. Expensive; beyond the scope of the class. REG/X_Rite_MSCCPP_ColorChecker_Passport.html QP cards pack of 3 - $17.95 Small pocket size, I primarily use this card. Unfortunately they became popular and the price increased. They have a matt surface, which is great for light reflection. The color and brightness match the Macbeth colorchecker. Delicate they cannot take a lot of abuse. REG/QP_Card_GQP101_Qp_Calibration_Card_101.html 2

3 Vello $9.95 This is an inexpensive, pocket sized card that can take a lot of abuse. It is plastic which is easily cleanable. The surface is luster which is not the best answer, but the card can be turned to diminish direct reflections. I found that it is 4 points green compared to the Macbeth card. You can easily establish a profile for your images with a 4point magenta tweak to overcome the green. REG/Vello_WB_CS_White_Balance_Card_Set.html After determining the correct exposure and capturing the image, take an additional exposure of the gray card. In Photoshop, correct color balance can be determined using the gray card and this setting can be applied to the actual scene. This step can save a lot of time in optimizing your images. If you are using a non calibrated, narrow gamut monitor, what you see on the monitor is not what you are going to get. Using a gray card simplifies the process. 3

4 Workflow It is not necessary to get close to the subject when capturing the gray card. And the card can even be out of focus. Just make sure that the same quality of light is falling on the gray card as the light falling on the scene. Select all the captures, including the gray card capture in the bridge and open in Camera RAW. Select the gray card image, then at the top, above the film strip, > select all. 4

5 With the zoom tool selected, right click, and zoom to 100%. At this magnification or above Adobe Camera RAW defaults to a 10 x 10 pixel dimension to sample the gray card. Use the third gray swatch from the left. There are different suggestions when using a gray card as to the correct swatch. Middle gray spreads out any possible color error starting with the correct color balance in the middle of the gray scale. Remember the most important part of the image is the mid tones. Once the image is opened in Photoshop, we will use the image levels to correct any minor differences in color in both the highlights and shadows. If you have bracketed your scene, select the capture that has the best midtones. Make any additional adjustments needed and open the image in Photoshop. Photoshop 1. Create an adjustment layer - > control J (mac command J ) 2. Save the capture in a new folder Selects 3. Select - > control L, or go to > Image > Adjustments > Levels 4. In the Channel palette, select each channel, Red, Green, and Blue independently. Check to make sure that each histogram extends to the full width of the graph. If not, grab the sliders under the histogram at either end and move them until they just touch the histogram. Do this for both the highlights and shadows for all three channels. If you have clipped the histogram at either end, this will not be possible. If you notice an off color bias in the print in either the shadows or highlights, slight corrections can be made using the Color Balance tool. 5