A Negative which has received the proper amount of exposure, usually possesses the following characters after the development is completed:--The image is partially but not fully seen by reflected light. In the case of a portrait, any dark portions of drapery show well as a Positive, but the features of the sitter are scarcely to be discerned. The plate has a general aspect as of fogging _about to commence_, but not actually established. By transmitted light the figure is bright, and appears to stand out from the glass: the dark shadows are clear, without any misty deposit of metallic Silver; the high lights black _almost_ to complete opacity. The _colour_ of the image however varies much with the state of the Bath and Collodion and with the brightness of the light. The remarks already made under the head of Positives, apply equally well to Negatives; that is, it will be difficult to secure gradation of tone, unless the object be _equally_ illuminated, without any strong contrast of light and shade. Hence the direct rays of the sun are, as a rule, to be avoided, and curtains, etc., employed when practicable. FIXING AND VARNISHING THE IMAGE. After the development is completed, and the plate has been carefully washed by a stream of water, it may be brought out to the light and treated with the Hyposulphite or Cyanide, until the unaltered Iodide is entirely cleared off. Some use a Bath for the Cyanide; but it is doubtful whether much saving is effected by doing so. The plate is again to be carefully washed after the fixing; and especially if Hyposulphite of Soda be used. Three or four minutes in running water will not be too long, or the glass may be left in a dish of water for an hour or two. If such precautions are neglected, crystals form on drying, and the image is injured. Collodion pictures should be protected by a coat of varnish, both Negatives and Positives having been known to fade when exposed to damp air without any covering (see p. 166). To prepare transparent varnish. Amber may be dissolved in Chloroform according to Dr. Diamond's formula;--about 80 grains of amber-beads or pipe-stems should be digested with one ounce of the Chloroform, and the clear portion separated by filtration. It may be poured on the plate in the same manner as Collodion, and dries up speedily into a hard and transparent layer. The Spirit Varnish ordinarily sold for Negatives requires the aid of heat to prevent the gum from chilling as it dries; the plate is first warmed gently and the varnish poured on and off in the usual way; it is then, whilst still dripping, held to the fire until the Spirit has evaporated. A few trials will render the operation easy to perform. White Lac dissolved in strong Alcohol or in Benzole has also been recommended for clear varnish.