Today’s Question: In the last few days I’m unable to use the Quick Selection Tool [in Photoshop]. I can have a plain blue sky and once I drag the quick selection tool over the sky I just get a sausage shaped selection the diameter of the tool. No pixels outside the diameter of the tool are selected. Have you any suggestions what the problem could be?
Tim’s Quick Answer: If you’re getting a selection with an odd shape when using the Quick Selection tool in Photoshop, the issue is almost certainly that you have the “wrong” layer active on the Layers panel. In most cases the best solution is to simply turn on the “Sample All Layers” checkbox on the Options bar for the Quick Selection tool.
More Detail: The Quick Selection tool will by default only sample the currently active layer on the Layers panel. So, for example, if an adjustment layer is active you will only be creating a selection based on the contents of the layer mask for that adjustment layer. Similarly, if you have an image cleanup layer active on the Layers panel, the Quick Selection tool will be creating a selection based on that layer (which likely contains relatively few pixels) rather than being based on the overall image.
The simplest solution is to turn on the “Sample All Layers” checkbox on the Options bar after selecting the Quick Selection tool, so that your selection will be based on the overall composite pixel values in the image, rather than being based on the currently active layer on the Layers panel.
In some cases, of course, you may prefer to create a selection that is based on the contents of a specific layer. In that case, you can turn off the “Sample All Layers” checkbox on the Options bar, but you then need to be sure to select the desired layer on the Layers panel by clicking on the thumbnail for that layer.
It is worth noting that the size of the brush for the Quick Selection tool can also have an impact on the selection that is created. If the brush size is too small, the selection will not cover a large enough area because the tool will not be sampling enough pixel values. You can adjust the brush size using the left and right square bracket keys (‘[‘ and ‘]’) on the keyboard. In general I recommend using a brush that is as large as possible for the area you need to select whenever you are working with the Quick Selection tool.