Meanings of fine shading in English

It deepens in its fine shading of blue as you follow it, true blue, the colour true hearts wear.

Very fine shading and nuance.

He never remembered to have seen such eyes-clear, dark blue-grey with fine shading of eyelash on the lower as well as the upper lid.

Moreover, his poetry is for the most part lacking in delicacy and fine shading; scarcely a score of his lyrics are of the highest order.

So with contrast of light and shade-fineshading, subtle distinction, everything-impossiblewithout care, patience, and trained attention.

In catching the fine shadings of diminishing sounds which came to him through the radio compass, there was not a man who could excel him.