Fairytale Scene - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 460

Figure 9.60
This places all the groups of layers we've created so far into one Smart Object.
This means we will always have access to the layers within it, but we can also con-
tinue retouching and using a filter without making a merged layer.
Note
If you're using a version of Photoshop earlier than Photoshop CC, you'll need to
create a merged layer at the top of the layer stack by clicking the uppermost
group (children), choosing Select > All, choosing Edit > Copy Merged, and then
choosing Edit > Paste. Name this layer night, and then go to Layer > Smart Ob-
jects > Convert to Smart Object.
3. We'll use the Camera Raw filter for the night effect, so choose Filter > Camera
Raw Filter. In the Basics tab, move the Temperature slider to -45, set Exposure to
-1.40, and set Clarity to +50 ( Figure 9.61 ) . Click OK to go back into Photoshop.