As magic items go, I find most of these tattoos to be very interesting! I might even try slipping one into the party treasure somehow...

That comes from a tattoo feat in the Lost Omens Character Guide correct? I believe that feat gives you the spell as an innate spell. Player Core pg 299 has the rules for innate spells. Innate cantrips are automatically heightened but other innate spells are not able to be heightened unless the ability that gave you the spell specifically says so. Unfortunately you can't heighten that spell by that ability.

@@GoatKingDice Thank you.

You would need Artisan's Tools (CRB 287) of the appropriate type or access to a work shop stocked with the correct tools. A set of artisan's tools costs 4gp.

@@GoatKingDice Is the cost of materials the listed price per tattoo?

@@sigasmund yes, when crafting you provide half that cost in materials at the start and provide 0-the other half at completion depending on how many extra days you spend crafting.