CTS Charts

These are the original source images that were used to produce the paper charts for CTS-1 thru CTS-4. The first 3 were produced with Adobe Photoshop as vector objects, allowing precise selection of shapes and colors. CTS-2 and 4 were made in 8-bit RGB mode using the sRGB color space. CTS-1 and 3 were made in 8-bit CMYK Color Mode. Each image is sized to print on 8.5"x11" paper with the 2 internal boxes sized at a 4x6 aspect ratio for capture by cameras. The 4-frame film strips were taken of color 8x10 prints on a copy-stand in direct sunlight on a cloudless day. 

The prints captured on the film strips reflect the colors after the printing process converts “pure” RGB or CMY colors to the CMYK mode used by printers. There is NO attempt made to suggest the colors on any of the CTS charts are “true” RGB or CMY colors. For example, the Cyan block on CTS-1 was created in Photoshop as “pure” Cyan set at 100-0-0-0 in the CMYK mode. However, when looking at the DSLR scan of that paper chart in Photoshop, the Cyan block shows 88-2-27-0-0 in the CMYK model. Very few (if any) printer can print “pure” color but will use a combination of inks to produce the best match possible to the referenced color.

CTS-1: The CTS-1 frame shows some resolution targets and the six primary screen/print color blocks (RGB and CMY). The upper left target is shown at 100% black, 50% black and 18% neutral gray.  The resolution targets show line pairs from 5 pixels to 2 pixels wide when scaled for an 8.5"x11" print.  The color blocks (Red/Green/Blue and Cyan/Magenta/Yellow) were originally set in Photoshop with CMY blocks set to pure CMY colors and the RGB blocks set to their matching CMYK equivalents. Cyan is 100-0-0-0 and it’s complement Red is 0-100-100-0.

CTS-2The CTS-2 frame is a set of sample color blocks that can be used like an IT8 target. The RGB values below the block show the RGB values as created in PhotoShop. The values inside the block show the CMYK values. Blocks 1 to 4 are representative values of average skin tones. Blocks 5 to 15 are sample colors selected from the standard Photoshop color schemas. Blocks 16 to 20 are white, 18% gray, 50% gray, 75% gray, and black.

CTS-3: The CTS-3 frame shows a color wheel and gradients to provide a reference sample of the wider color spectrum with gradual changes between the primary colors. The source image is set in CMYK mode in the sRGB color space. The right side of the image shows primary and secondary colors as they transition to the next color in the color wheel. This chart provides an excellent target for reviewing how hue/white balance adjustments affect various colors and gradients.

CTS-4: The CTS-4 frame provides a test box set with common everyday items that can be used to color balance the image. CTS-4 is a frame from a printed digital image. This chart provides real world items and colors as they appear on the same print paper and captured with the same lighting/setup as the first 3 color charts. The original source image was taken of the test box in direct mid-day sunlight with a DSLR. This chart allows quick comparisons after negative conversion and white balancing and the effects while trying to “fix” a specific color.

The CTS strips are provided in set film stocks. The color reversal (slide) film set uses Fujifilm Provia 100F color reversal film. The color negative strip uses Kodak Portra 400 film. The film images were captured from printed 8.5”x11” charts mounted on foam board and photographed in direct sunlight on a cloudless day. They were taken with a Nikon N80 camera with a Nikon Micro Nikkor 60mm f2.8G ED lens. A printed 4x6 hardcopy of the 4 charts is also provided for quick color comparisons to scans from the test strip.

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