US1971261A - Method of making ornamental mirrors - Google Patents

Description

Aug. 21, 1934. M. H. HARMON 1,971,261

METHOD OF MAKING ORNAMENTAL MIRRORS Filed Sept. 7, 1932 I Patented Aug. 21, 1934 uuirso stares Msrrroo or MAKING ORNAMENTAL MIRRORS Melvin H. Harmon, High Point, N. 0;, assignor to Logan Porter Mirror Company, High Point,

N. (3., a corporation of North Carolina Application September 7, 1932, Serial No. 631,987

1 Claim.

The invention relates to ornamental mirrors and has for its objects the provision of a method of making ornamental mirrors at a relatively small increase over the cost of making a plain mirror of similar size. The mirror and the method of making the same is illustrated in the accompanying drawing, wherein:

Figure 1 is a face view of the mirror provided with a very simple design. Fig. 2 is a section on the line IIII of Fig. 1, the films of material shown in this and other figures being much exaggerated in thickness for the purpose of clear illustration. And Figs. 3 and 4 are sections showing steps in the'operation.

Referring to the drawing, 1 is a sheet of transparent material, such as glass; 2 is a photographic film which forms the pattern or ornamentation; and 3 is a precipitated metallic film such as silver or mercury which covers the main body portion of the glass. The film 2 (which is stained or colored, as later described) and the film 3 are disposed so as to give an ornamental effect, the particular design shown being of very simple character, but it will be understood that designs or pictures of the most elaborate character may be made by the process at no greater cost.

In carrying out the process, the glass sheet is first coated with an emulsion 2 sensitive to light (Fig. 3) such, for example, as the so-called cold top enamel in the photo engraving art. The desired design or picture is then impressed on the coating thus provided, either by direct contact printin from a photographic negative, or by the projection of an illuminated image thereon. The latent which is thus developed is treated with a suitable developer so that the light treated portions of the film are rendered insoluble, the general details of this treatment being well known to those skilled in the photo graphic art. The developing fiuid, however, differs from the ordinary fiuid for this purpose in that it contains a suitable coloring matter or stain, so that the developed image, while semitransparent, has a substantial shade of coloring not present in the ordinary photographic negative. This color may be varied at will depending on the stain placed in the developer. The plate is now washed in a solvent which removes all of the emulsion coating except the part 2 which has been rendered insoluble and colored by the developer as above described. The sheet is now ready for silvering and after being washed with the usual tin solution, a coating 3 of silver is precipitated over the pattern 2 and over the part of the surface of the sheet surrounding such pattern.

The result achieved is a colored pattern surrounded by a mirror surface, which is ordinarily silvered, but may be any kind of precipitated metal, such as copper, gold, mercury, or lead sulphide. The coloring of the photograph film leaves it partially transparent, so that the silvering behind the pattern shows through, rendering the pattern bright and attractive.

The silver or other precipitated coating may be protected in any of the ways known in the art, such as by lacquer, copper, paint, or copper plating, which require no illustration.

In the ordinary mirror, the ornamentation will usually be around the edge of the plate, leaving the central portion plain, but when the glass is to be used as a plaque, dresser top or the like, where the ornamental appearance rather than utility as a mirror is the main consideration, the ornamentation may be at the center as illustrated or may be distributed over a large part of the plate area. It will be understood, therefore, that the term mirror as used herein is intended to describe the article whether much or little of the area is covered by the ornamental design and re-- gardless or" the location on the plate of such design.

The sensitized emulsion or enamel with which the glass is first coated may comprise gum shellac sensitized with ammonium chromate. In this case, the developer preferably used comprises two parts, first a stain preferably consisting of alcohol in which a coloring medium, such as a yellow or brown dry color dye, or a mixture of the two is dissolved, and second, a mixture comprising sodium bisulphate, pyrogalic acid, potassium bromide, sodium sulphite and sodium carbonate. These two mixtures are preferably separately prepared and then mixed together. It will be understood, however, that the use of a wide range of developers is possible, depending on the character of the sensitized film, and that the coloring materials may vary depending on the colors de sired. The amount of the coloring ingredient used is relatively small, so that the coloring of the photograph is relatively light (as heretofore pointed out), leaving it semi-transparent so that the silver subsequently applied will show through it rendering the picture brighter and more attractive.

What I claim is:

A process of forming a decorative reflective article which consists in coating the face of the sheet with a photo-sensitive emulsion, exposing portions of said coating to the action of light, applying a developer containing a coloring stain to form a colored semi-transparent pattern which is not subject to the action of a solvent, applying a solvent to remove the part of the coating which is soluble, and then covering the pattern and the uncoated portion of the sheet with a metallic film precipitated from a solution.

MELVIN H. HAaMoN.

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