what victor wants to do is different than what eric renner did.
eric renner made a 7 pinhole camera and used it to make a relatively short exposure.
then processed the paper. what victor wants to do is leave his pinhole open for such an extended period of fime
that the image of the moon "stains" the paper and creates a solar(lunar)graph. the paper isn't developed ( or it will turn black )
and it can't be fixed ( or it turns white ) ... it is ephemera ... and it has to be skanned, or rephotographed or xeroxed ...
good luck !