Various portions of the Paleolithic period were characterized by an exceedingly harsh climate, forcing humans to seek shelter. Evidence of paleolithic dwellings have been found in cave mouths, under rock overhangs, and in the open. Excavations of Paleolithic dwellings find only permanent materials like stones and bones, impermanent materials such as wood and animal skins rotted away long ago. Rock supports and occasional post holes describe dwelling layout and framework. A framework presumed to have supported animal hides. Hide tents are a tradition that cold climate indigenous peoples employed until the onset of the modern era. The drawing below is of the Upper Paleolithic site at Buret.

The question is how dark would it be inside of one of these Paleolithic hide tents? The light level inside would depend upon the opacity of the hides. Our experiment:

These two pictures, taken moments apart, have an exposure difference of 26 stops. The photographic term "26 stops" translates to 2 to the 26th power in mathematical terms, or roughly 67 million times less light behind the hide. The light absorbing capacity of a cold-climate animal's hide would make for a fairly dim tent interior.

Below is an illustration of large hide tents from the Upper Paleolithic site at Gönnersdorf.

Illumination inside an Upper Paleolithic tent was provided by a fire in the hearth and by daylight entering through the vent hole in the roof. Neither the fire nor the vent hole precludes the formation of a camera obscura.

On the right is a one inch hole in a covered window that projects an upside-down image of an adjacent brick building on to a board. Four and a half feet from the hole is a 100 watt light bulb. Out of frame are other light sources, including another covered window with a hole that projects another image, numerous light leaks entering from another bank of covered windows, and an open door at the end of the room. Because of the astonishing dark accommodating powers of our eyes, this is workable light. The point of this picture is to show that a camera obscura does not require complete darkness, only a dimmer environment than the outside world. Other light sources can indeed exist inside the space alongside the camera's image. How, when, and where an image is seen depends to great extent on the angle of the sun in relation to the location of the hole.