[How do i create a transparent line drawing from a photo]

Pauls/v_kyr thank you so much for your help, it appears I was just missing that final step of Filters -> Colours ->  Erase White Paper
Now if i add the exported png into a word doc ontop of coloured boxes it looks like its pencil drawing on top.

Thank you so very much for your help and your very quick replies, I really appreciate it. 

[How do i create a transparent line drawing from a photo]

I have a photo of a building, which i would like to change into a black and white pencil drawing where all the white is transparent.  I am going to be printing the image on brown paper so i want it to look like a drawing on the paper as apposed to a picture on the paper. 

I have followed the tutorials on how to take the picture and convert to a line drawing. However the drawing is not "see through", i.e.. there is lots of white so when i export the image as PNG and put it on a coloured background it looks like a picture, not lined drawing on the coloured paper.

Can anyone advise me how to do this in affinity

Thanks
Sarah

My original Image and my Affinity produced png put on a coloured backgroun



This is sort of what i want, i.e if this person was printed on brown paper you see black lines on brown and not any white