imperceptible

If you look at the map below the change is almost imperceptible.

For Riley, the finish line she is approaching is neither cloaked in neon nor so thin as to be imperceptible.

The graceful observations of “Janet Planet” render the two characters’ development almost imperceptible, hidden behind silences and what goes unsaid.

Perhaps the two bighorn sheep were fighting over territory or food, or maybe there was some ovine slight imperceptible to human eyes.

Spinning electronic fibres results in devices that are imperceptible to the user, but without a high degree of sensitivity or sophistication, and they're difficult to transfer onto the object in question.