Use 'touch up' to describe slight, delicate adjustments to something that's almost perfect.

Subtle Adjustments

'Touch up' often implies the work is in its final stages and only minor fixes are needed.

Final Stages

'Touch up' in makeup means quick fixes to maintain appearance, not a full reapplication.

A good 'touch up' on makeup or paint should be barely noticeable, blending seamlessly.

In digital editing, 'touch up' is used to make subtle enhancements to improve image quality.

'Touch up' in computing indicates a focus on detailed refinements, like removing blemishes.