LOGICIELS
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RBG2HSB
This form will transform RGB values to HSB values. It is intended to be used with Photoshop Camera Raw calibration steps, a Macbeth Color Checker, and a digital image of the Macbeth squares. The objective of this RGB to HSB transform is to assist the user with determining whether hue or saturation needs the most correction during ACR calibration. Since the color metrics are all interrelated, it is useful to be able to evaluate hue, saturation, and brilliance as one adjusts the ACR calibration hue and saturation sliders. Since the ACR dialogue is modal one cannot us the Photoshop "info" pallet for help. If and when ACR shows color values in both RGB and HSB, this page will be unnecessary.Color Conversion Algorithms Contents RGB to HSV & HSV to RGB The Hue/Saturation/Value model was created by A. R.
Color Conversion Algorithms
Introduction The subject of Adobe’s quasi 15-bit math has been discussed in the Adobe forums before. In addition, errors in the Lab mode histograms and in the JavaScript SolidColor object have been posted in the scripting forums and acknowledged by Adobe. This discussion is simply a recap of some of these observations. The core problems seem to be related to Lab mode numbers, but since this is the Adobe reference for color conversions it is important. The fact that RGB-LAB-RGB conversions will alter colors has also been discussed.
Adobe Math
ImageMagick ® is a software suite to create, edit, compose, or convert bitmap images. It can read and write images in a variety of formats (over 100) including DPX , EXR , GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to resize, flip, mirror, rotate, distort, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves. The functionality of ImageMagick is typically utilized from the command line or you can use the features from programs written in your favorite language.
Command-line Options
Selecting Target Color Checker Numeric Values I have seen several different suggestions about what the proper numeric values are for the colors in a Gretag Macbeth twenty-four patch Color Checker. For some strange reason, most of these show some color shifts in the neutral patches. This did not seem right, so I have pursued some research.
GretagMacbeth Color Checker Target Values
ACR Camera Calibration and Validation
Introduction This article will describe multiple scripts for Adobe Photoshop CS color calibration. I will assume that the reader is already familiar with the basics of Adobe Camera Raw (ACR) and the controls provided for color calibration.