The silver shows as white/gray on a black background with wetplate. Conventional printing paper, the silver shows as black on a white background.
You can prepare and present negatives with the emulsion side up against a black background and get a positive image if viewed correctly.
Here is a conventional negative held against a black background producing a Left/Right reversed positive image as a wetplate would.
I presume you have familiarity with wet plate images viewed in person and are not trying to reproduce these fake images seen on internet:
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