Sometimes picking a color doesn’t match the original. Most likely this is caused by a color profile mismatch.
Colors are represented with color profiles, and each one has a different gamut (or range) of colors they support. There are many different color profiles, and color values from one profile can display differently in another profile. Images, applications, and even your display have their own color profile.
When you pick a color from a pixel on the screen, that color will be picked according to your display’s color profile, rather than the color profile of the application you’re using.
For example, if you’re picking a color from an image with an sRGB color profile, but your display’s profile is set to something else, the color might end up different than the color from the original image. This happens because the color from the image might not be within the range of the display’s color profile. If the color is not within range, then the colors values will be shifted to fit within it.
In other words, if you have an sRGB color with a red value of 100, the red value might display as 102 if the 100 red value is not in the range of your display’s color profile. This is what causes colors to be different than what they originally were.
Because each color profile supports a different number of available colors, any conversion from one format to another will always yield a slightly different color than the original.
All color pickers work this way.
The Solution
In order to pick accurate colors, you must make sure that your display, your application, and ColorSlurp all use the same color profile. If you’ve picked a color from an image and the values are not correct, most likely the image’s color profile is different.