is practically two ; therefore by consulting the table given under Enlarging, we shall find with a 5-in. focus lens that our lens must be 15 in. from the plan andin. from the focussing
screen. Supposing our camera does not rack out sufficiently far, we must improvise an extension by means of a 3-in. or 4-in. cone, or else by adapting one of the cardboard cases used for sensitised paper. If we have a choice of lenses, we may pick that one which is of sufficiently short focus to enable us to use the camera without any additional extension. The next point is to place the axis of the lens exactly central with the print, and the focussing absolutely parallel with the plane of the line drawing. It is hardly necessary to dilate upon this, as any tyro can do it. Then comes the question of lighting. This should be so diffused that the grain of the paper does not show by casting a shadow. A short exposure should be given, if any-thing under-exposure, because we want to get hardness and contrast. No guide can be given for exposure, as it depends so entirely upon the actinic power of the light. The developer may be either quinol, or Edwards's pyro redeveloper may be used ; we prefer the former. Development should be continued as far as possible without any blocking of the lines showing; if this shows, immediately stop the development, wash, and fix. After thoroughly washing, the negative should be cleared till the lines show as absolutely bare glass, with the ground opaque. For this purpose we specially recommend Howard Farmer's reducer. (See Reduction of Density.) Then, after thoroughly washing, if not dense enough, intensify. (See Intensification.)
Linotype. A term applied to printing on linen and other textiles. (See under Silk. For enlarging on canvas see Enlarging.)
Lippmann's Process. See Photography in Natural Colours.
Lithium (Ger., Lithium; Fr., Lithium; Ital., Litio). Li 7. A comparatively rare metal occurring in lepidolite, lithia-mica, petalite, and triphane. It can be obtained by decomposing lithium chloride by a galvanic current. It is a soft silvery-white metal which decomposes water, and is remarkable for its extreme lightness (Sp. Gr. 0-59).