The light must illuminated from the top side of the page. This means that the shadows of the Braille bumps need to be on the bottom side. Light should not come directly above, beside, or below the page.
If the Braille paper is placed on a wall or otherwise stood up and photographed from the front, the shadow of the Braille dots will be more likely to form on the bottom side, making it less susceptible to the shadow of the smartphone.
Braille symbols should be neither too small nor too large. The optimal size is an entire A4 page as the image area.
