4x5 Film Light Leak

I got my sheets of 4x5 film back and every 4 sheets shows light leak on them. I realized I may have done that when I first opened the box and put them in the holders while in the changing bag. Dont ask me how.

 

If light got in while the box was open, what are the chances the whole box is fogged? Or if not, how many sheets down should I go before the remaining amount will be okay? I figured a stack of sheets on top of each other might help protect the ones below? What are my chances I still have some good sheets? Its a box of 50 and only 10 or less sheets have been used.

How about starting from the bottom of the pile.

What are my chances I still have some good sheets?

 

A very good chance, only the edges of the first few sheets would be affected . It's not likely the change bag would have a light leak though, perhaps look elsewhere to locate the problem.

The light leak was a sliver of light in the middle of the sheet. So yes I seem to remember I did something with the dark bag that would have caused that. All my holders are fine, as they worked fine before and I used two holders for my B&W sheets.