The ND 3.0 Neutral Density filter is a very dark piece of gray glass. It absorbs 10 stops of light from your base exposure and allows you to make long exposure photographs with standard film in daylight. If your base exposure without the filter is 1/125 sec at ƒ/16, with the filter you’ll need to lengthen the shutter speed to 8 seconds.
I used a Tachihara 4×5 Field Camera and a Schneider 210mm ƒ/5.6 Symmar-S lens to capture the image on Kodak T-Max 100 (TMX). The exposure was 8 minutes at ƒ/32.