"If Vermeer Can Do It, So Can I" :
use the technology of the day, that is.
This is a quote from Essential Vermeer
And here is the link:
" The Camera Obscura
It is now generally accepted that Vermeer employed a simple, box-like device, called thecamera obscura,as an aid to his painting, although there is great debate as to exactly what extent he did so. Phillip Steadman, a London architect turned Vermeer notable, produced convincing circumstantial evidence (the camera obscura leaves no physical marks of its use in painting) that Vermeer may have even projected image of the camera obscura directly on his canvas where he then comfortable traced its principal outlines with brush and paint. "
I often use the drawing apps on my phone to try out ideas for paintings. It's so much better to see the effects of changes made to paintings before one goes mucking about and wrecks it all!!!
The apps I use are
DrawCast and You Doodle.