Ghost Tabby may only be present on solid black-based cats.
Ghost tabby occurs because, technically, cats always show their corresponding tabby pattern. The presence of the agouti gene creates a contrast between the "stripes" and the "base" color, allowing a cat to fully show their tabby pattern whenever agouti is present. Sometimes, when the cat's undercoat is light enough, the tabby pattern can show through!
As a result, for a cat to show ghost tabby, there must be some form of undercoat present. This could be from their regular undercoat, silver smoke or golden smoke.
Some things to keep in mind:
The stripe color should be the exact same color as the base coat. Any gradients added onto the base coat must also be applied to the stripes.
Stripes will only show where there is lightening of the coat. Stripes must not be visible anywhere else.
Cats will always show their corresponding tabby pattern (the "genetically" line will let you know their tabby pattern).
Regular undercoats and silver/golden smoke undercoats have different rules, but both may be used to show ghost tabby.