RGBer

Determine RGB, HSV, and Hex values for any color.
Use the RGB Color Mixer to find the perfect color by using the sliders to adjust just the right amount of red, green, or blue. With v2.5, you can now tap on a value to edit it directly and RGBer will calculate all the other values.
A Grayscale Meter makes determining the right mix of RGB values to get the gray you want.
Select a photo from your photo library and tap on any part of the photo to get the RGB, HSV, and Hex values of that area in the image. Zoom and pan through your photo to find the spot you want to measure, then just tap the spot to get the values.
RGBer lets you snap a photo, zoom and pan to the area that you want, and tap on the photo to get the RGB, HSV, and Hex values. Afterwards, you can save your new photo to your camera roll for later reference.