Increased differentiation between the subject with the rest of the picture is commonly achieved with narrowed depth of field, or by changing the luminosity of the subject relative to the rest of the photo through post-processing techniques like vignetting or selective brightness manipulations with an adjustment brush.
Making use of colour temperature manipulation is another subject isolation technique I sometimes use. For example, in the photo on the left, I find the squirrel blends in too much with the rest of the picture (evidently, evolution favours squirrels that are camouflaged with the forest). On the right, I used the Lightroom Adjustment Brush to cool the background by (1) Masking everything save for the squirrel and the main branch and (2) Sliding the Adjustment Brush “Temp” slider to -5 (i.e. 5 units cooler).
The slight cooling of the background better isolates the squirrel while providing a bit of depth to the photo.
Some notes on my application of this technique:
- I typically go for subtle treatment. Though side by side the manipulation is apparent, the picture on the right would not appear abnormal in isolation.
- I tend reserve warmth for the subject, while cooling the rest. There is no reason this could not be reversed….
Hopefully this opens up some new ways of working with your photos!