Classic Color Meter is a enhanced replacement for Apple's DigitalColor Meter application. It restores all functionality previously available in OS X 10.6 Snow Leopard's DigitalColor Meter and adds many additional features:
• Display modes
• RGB percentage
• RGB decimal (both 8-bit and 16-bit)
• RGB hexadecimal (both 8-bit and 16-bit)
• Hue/Saturation/Brightness (HSB)
• Hue/Saturation/Lightness (HSL)
• Y'PbPr and Y'CbCr (both ITU-R BT.601 and ITU-R 709)
• CIE 1931, CIE 1976, CIE LAB, and Tristimulus values
• Commands
• Lock cursor position / X axis / Y axis
• Adjust magnification (1x/2x/4x/8x)
• Adjust aperture size
• Show/hide cursor coordinates
• Update preview continuously
• Hold Color (allows editing of color in RGB and HSB modes)
• Save/Copy preview image
• Copy Color as Text, Image, or as a NSColor/UIColor/HTML/CSS code snippet
• Paste Text as color
• Preferences
• Adjust aperture color
• Assign actions for clicking/dragging the color swatch
• Use lower-case letters for hex values
• Include pound sign prefix for hex values
• Show visual guides when locking cursor position
• Show component sliders when in Hold Color mode
• Assign global keyboard shortcuts
• Move mouse cursor with arrow keys
─ Regarding ColorSync ─────────────────
Regarding ColorSync issues reported in a review:
All color meter utilities in OS X use the RGB values sent to the display, with no additional ColorSync conversions applied.
If an image has a profile assigned to it, the viewing program will perform a color space conversion. The only way to accurately sample the original raw values in the image is to either use the program's native tool (for example, the Adobe Color Picker in Photoshop - the Apple Color Picker option will be post-conversion) or display the image sans profile.
When you select "Display as sRGB" and others in color meters, an additional color space conversion is applied. This results in colors close to the original values, but not quite, as both conversions round values to the nearest integer.
For more information about color meters and color space conversion, select Help → Learn about Color Conversion from the Classic Color Meter menu bar or visit iccir.com/articles/osx-color-conversions