Solo and ai:solo,0%

An image containing a single person. No one else should be visible in the image.

that means only one copy of the character. These situations should not be tagged solo:

These situations should be tagged solo focus, not solo:

Pictures focusing on one character among a crowd of nondescript, less detailed people.
Single characters engaged in sex acts with faceless or out of frame characters.

Situations that can be solo include:

Single characters being depicted from multiple views.
A single character with one or more inanimate dolls or photos of other characters.
A single character with pet or object characters.
A single animal or creature with no humans present.

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