Use 'discernible' to describe things that aren't immediately obvious, but can be noticed upon closer examination. The painter's brushstrokes are barely discernible to the casual observer.
Pro Tip 2/3
Positive Changes
'Discernible' often refers to improvements or positive changes that have become clear or distinct. Her confidence has shown a discernible growth since she started the new job.
Pro Tip 3/3
Objective Clarity
Use 'discernible' for describing something that can be identified objectively, not just subjectively felt. The benefits of the new policy must be clearly discernible to gain public support.