No idea but I doubt it will work well even if it does work.
A UV light box is cheaply made or bought, and will give much faster and consistent results. Waiting for a bright midday sun is just going to annoy you.
Otherwise, consider the Toner Transfer method. If you've got a laser printer you've already got half of what you need - then you just need a laminator (preferred) or some skill with a clothes iron.
I prefer that method as there's less chemicals to buy etc.
--- In Homebrew_PCBs@yahoogroups.com, James English <jimenglish123@...> wrote:
>
> Hello, I'm new to this group, though not new to electronics. Does anyone out there have experience with exposing a photosensitive board through a negative to sunlight? A man at Injectorall told me that about six minutes at noon on a bright sunny day but that doesn't seem to work.
>