>>3254502You do know that positive paper is a thing, right? You'll be making useless inverted photos with normal paper. It's quite expensive though and it has an ISO of ca. 3, so your pinhole camera will have enormous exposure times, but I guess that's expected of a pinhole camera.
https://www.fotoimpex.de/shop/fotopapier/harman-direct-positive-papier-naturglanz-baryt-13x18-25-blatt.html