How best to adjust the colour of different parts of an (all raster) image that are on the same layer?

Question

I am attempting to experiment with different colours for the grey, orange and pink areas of this image. They all appear with no separation on a single layer.

So far I've tried selecting and separating them on to their own layers, then adjusting the hue/saturation of those layers. This did not work, however, as I only succeeded in adjusting the entire image.

What's the easiest way to accomplish this? Is there a easier way than using hue/saturation and adjustment layers? I can't quite figure out how the resulting colours correspond, so it would be easier if I could select the colours I wished to use directly...

Thank you in advance.

Answer 1

You could use an Adjustment Layer to adjust the hue and saturation non-destructively:

To confine the effects of an adjustment layer to specific image layers, select the image layers, choose Layer > New > Group From Layers, and change the Mode from Pass Through to any other blending mode. Then place the adjustment layer at the top of the layer group.

Help Docs: Photoshop / Adjustment and fill layers

Answer 2

I would recommend JohnB's approach as the best approach, but an interesting alternative is to use the color range to mask the buttons, accessed through Select → Color Range...

Because these are really distinct bright colors color range does a good job of selecting the specific colors you want. You would have to set the tolerance somewhat low and Shift+Select different colors in the image. This creates a selection of your buttons. You could then create a copy of the layer and use the selection as mask. I would feather the mask slightly in the Properties window as well.

You could then use the Channel Mixer and your masked layer as a clipping mask for the adjustment

As you can see some of the value is being lost in the midtones, but it is still pretty neat if you ask me.