Thank you for THIS. the vid actually reproduces the very process...which has been something quite difficult to find described specifically and clearly anywhere online. The most clearly descriptive source which actually shows how the heliograph was developed.

on 8:27 I didn't get the term she said.... the ^%&totype? send me a msge on my fb if anyone would bother...

they dont say his full name one single time in the video. thats why i'm here. i wanna know how to pronounce that shit