In use the subject is viewed through a blue filter, turning a disk causes a series of smaller holes to cover the filter. When the shadows are no longer distinguishable the dial shows the shutter speed and aperture pairs.

In use the subject is viewed whilst revolving a dial until the shadow detail disappears. A table gives an index letter based on plate speed and aperture to be used. The index letter is then found on the dial which will point to the shutter speed to be used.

The meter consists of 8 grey tints with cut outs in the centres of each. In use the subject is viewed to see which tint matches the subject. A table then shows the shutter speeds and apertures for the tint. The meter is for Extra Rapid plates only. As the subject is viewed without any intervening filter to remove colours it is nearly impossible to distinguish between grey tint and colour.