Isolating colours in your photo can look great sometimes. I’ll be guiding you through the basic way of isolating a colour with Photoshop Elements, however this can be done in any other version of Photoshop too.
Let’s start with an image. Take my image of a leaf for example:
Select the ‘quick selection tool’, and highlight the object with it. It can be a bit over-predictive sometimes, so hold down the alt key to un-select anything you don’t want. It should look something like this: Now, right click your selection and click ‘select inverse’. This will reverse your selection. Now access the saturation meter. On Photoshop Elements, this can be found under the ‘quick’ tab. Lower the saturation down to zero. This will make the surrounding area greyscale. Congratulations! You have isolated your object. *Optional* In this case, our grass is very dark in contrast with the leaf. We can counter this by accessing the lighting. Then, lower any of the lighting effects (shadows, midtones, etc.) to lower the darkness of the grass.Have fun Photoshopping!