The ferro-plate is held between the thumb and first two fingers of the left hand. The collodion bottle is held in the right hand, and the collodion is poured on the right upper end of the plate, flowed to the left upper corner, by deflecting the plate in that direction, and. then down the left side toward the hand, and the excess run back into the bottle from the right lower corner, when it has all run off, the plate should be gradually brought to a perpendicular position and rocked from right to left, that is, perpendicular to the end, then to the side, until the film has set or become fixed, which may be ascertained by touching the film at the lower corner of the plate, when, if it breaks and does not run farther, it has set and should, without delay, be immersed in the silver solution, where it should remain until it has become fully sensitized, which will be in from 2 to 5 minutes.

The plate should be lowered into the bath by one continuous motion; any stoppage will cause a line and spoil the plate.

The plate is sensitized when on removing it from the bath it presents a smooth, yellowish surface; if it shows lines as of water running off a greasy surface, it is not coated; return it to the bath.

Exposure Of The Plate

The plate having become sufficiently coated is taken from the bath, well drained, and placed in the holder or shield, and a piece of glass of the same size put behind it, which is to receive the pressure of the spring on the door of the holder, and force the plate into its proper position evenly, so that all parts will be in focus.

The holder containing the plate is then taken to the studio, or light room, where the subject, we will say, has already been posed; the camera set and focused, the exposure is then made, after which it is returned to the dark room for development.