4.--Bringing out the picture; in other words rendering it visible.
5.--Fixing the image, or making it permanent--so that the light may no longer act upon it.
6.--Gilding: or covering the picture with a thin film of gold--which not only protects it, but greatly improves its distinctness and tone of color.
7.--Coloring the picture.
For these various operations the following articles--which make up the entire apparatus of a Daguerrean artist--must be procured
1.--THE CAMERA.--(Fig. 5.). The Camera Obscura of the Italian philosophers, although highly appreciated, on account of the magical character of the pictures it produced, remained little other than a scientific toy, until the discovery of M. Daguerre. The value of this instrument is now great, and the interest of the process which it so essentially aids, universally admitted. A full description of it will therefore be interesting.
The camera is a dark box (a), having a tube with lenses (b) placed in one end of it, through which the radiations from external objects pass, and form a diminished picture upon the ground glass (g) placed at the proper distance in the box to receive it; the cap c covering the lenses at b until the plate is ready to receive the image of the object to be copied.
Thus a (fig. 6.) representing the lens, and b the object desired to be represented, the rays (c, c) proceeding from it fall upon the lens, and are transmitted to a point, which varies with the curvature of the glass, where an inverted image (d) of b is very accurately formed. At this point, termed the focus, the sensitive photographic material is placed for the purpose of obtaining the required picture.
