Photoshop’s Eyedropper is our go to tool when we need to take colour readings from an image.
However, by default it’s configured to take a “Point Sample” reading meaning only the pixel directly beneath the cursor is analyzed. In most working conditions this is far too precise as most types of image will have variations in colour due to noise/grain within the image.
In the Control Panel along the top of the screen you’ll see a Sample Size: drop-down menu. Here we can select to take an Average colour reading based on a grid of pixels, anything from 3 by 3 up to 101 by 101.
To put this into context the image below shows a blow-up of an 11 by 11 pixel area. Even though the skin texture in this shot is pretty even there’s still a good deal of variation from pixel to pixel. Notice also how small the sample area actually is – this will be even more pronounced working with high resolution images. The image below is cropped but this part of a 20 meg so it’s not unusual to work well above this size.
The size of grid you choose will vary from image to image based on what you need to sample and the size/resolution of your image. Certainly it’s advisable to work with at least 5 by 5 in most day-to-day tasks. This will give more accurate colour readings but still allow you to sample precise areas.
But what about when we’re working with larger areas of colour and greater amounts of variation.
Suppose I wanted to get an average of the skin tones in my image. Fortunately we have at our disposal a specific blur filter that we can go to for such tasks.
With a marquee active, go to Filter>Blur>Average. This will analyze the pixels in your selected area and blur these out to their average colour.
In the example below I’ve selected an area to include highlight and shadow skin-tones then copied this so we can see the side-by-side comparison.
Colour, and peoples perception of it, is pretty subjective. Clients will often ask me to ‘match’ colours from an image where there are pronounced variations in colour and tone so being able to quickly average out an area of colour can be very useful.
In the image below I’ve averaged a large section of the mountain to try and get a colour that will sit nicely with this picture when used in a page layout. The section that’s been averaged contains, greens, greys, blues even cream colours – the average has come out as a soft grey/blue.
For a quick way of seeing how this colour will sit with our image we can draw a marquee around our image and fill it with the colour to create a frame. Framing the image like this will give us a pretty good sense of whether the colour harmonizes the right way.
So, for general day-to-day colour selection the Eyedropper is a great tool, especially when the Sample Size: is configured for greater accuracy. And for larger selections we can call up the Average blur to lend a hand.