Put a double layer of a red filter (Amazon), over the door window in the
trailer. This might be a temp thing, not sure. I can no longer open the
windows with the filter on. Am also going to make black out cloths to
allow film darkroom work. Ordered some more of this red filter material
for the large side window. I will paint the roof hatch red as well later
this week (thanks Christopher for that suggestion). If this all works
out I will try using the trailer for the next series of wet plate
tintypes. Am tired of using the house darkroom, up and down, up and
down, up and down the stairs.