The In-Spec barcode can only be confirmed by a verifier, but it should exhibit the following visible characteristics.
The normal barcode will have complete, even bars and clear, distinct spaces.
The rotated barcode will have complete, even bars and clear, distinct spaces. Although it may not look as good as a slightly dark barcode, the barcode will be In-Spec.
In both normal and rotated styles, small alphanumeric characters look complete.