CHROMiX

Automatic hue with a specific lightness and saturation?

I need to develop two or more hues that have the same lightness and saturation when printed on paper or presented on a computer monitor. I have been doing this by trial and error with a spectrophotometer. I was wondering if there was any product that would enable me to specify a specific lightness and saturation and simply output several hues that have that exact lightness and saturation. For instance, a red with the same lightness and saturation as a green. Is there anything like this available? Is this possible? More specifically, I would like a program that can interface with a spectrophotometer such that after taking a reading with the spectrophotometer, the program would output a variety of hues with the exact same lightness and saturation as the originally measured color.

You can do something like this in Photoshop. If you double-click any color swatch to bring up the color picker dialog, it will allow you to input color values in many different forms: RGB, CMYK, Lab and HSB. The last one is Hue, Saturation and Brightness. If you leave saturation and brightness alone, you can dial in whatever hue you wish across a 360 degree circle. If your monitor is calibrated, that should give you what you need when presenting on a monitor.

The printed version of this might not be as accurate. If you can get Lab readings from your spectro, you can convert them into LCH at Bruce Lindbloom’s site and convert the other way around too. (From LCH to Lab.) Even this would require some trial and error - more to confirm what patches you’d be reading have the same lightness and saturation.

The Worksheet in ColorThink Pro has the ability to instantly convert a color list of Lab values into LCH values if that helps you any.

Give us some more information about what your ultimate purpose is and we could maybe give you better information.