US2047124A - Method of making reliefs - Google Patents

Description

July 7, 1936. G. B. CUTTS ET AL METHOD OF MAKING BELIEFS Filed July 14, 1954 IN VENTOFFS.

Y R 33 o A T A T M A ea Gk Y s Patented July 7, 1936 George B.'CUHZS, .Brookline, and Harold Jackson, :Jamaica Plain,- Mass.; said-Jackson assignor to said Outts Application July 14, 1934, Serial No. 735,196

2 Claims. (on. 41-25) This invention relates to a method of producing reliefs, intaglios and thelike and particularly artistic has-reliefs in metal, by the use of mechanical and chemical agencies and without the aid of manual carving, molding or sculpture of any sort.

The objects of our invention are first to dispense with manual sculpture in the making of reliefimages or, as will appear, also intaglios,

without sacrifice to the artistic qualities of the relief, by using photography to produce a relief of the subject in a material which maybe used as a pattern for molding the relief in metal and, second, to provide a method of using the pattern so made to produce a relief in metal which is artistic and a faithful reproduction of the subject.

We have found that we are able effectively to produce the relief pattern by the use of photography by utilizingthe property of certain colloids such as gelatin suitably treated, to swell after photographic exposure to the-subject to reproduce the subject in relief. We havealso' found that the gelatin relief so made can-be most effectively employed as a patternto reproduce the relief in metal by forminga negative mold from the gelatin pattern and spraying themold with finely dividedmoltenmetal.

' The gelatin colloid wf ch we employ to make the relief pattern has the characteristic of swelling if immersed in a suitable" chemical bath and this tendency of the material to swell canbe restrained by treating it with certain light-sensitive salts and thenexposing the colloid'so treated tolight prior to the swelling bath. a on thisprinciple if certain portions of the salt-impregnated gelatin are exposed to light while other portions are shielded therefrom, the" shielddportions will swell to form a relief contrast with'the-exposed portions. J l 1 The gelatin relief can'be effectively" used as a pattern to produce the-relief in metal =by first making a negative mold from the gelatin in'a suitable material, suchas'plaster of Paris, which will take the impression without distortingzthe gelatin pattern. After the plaster mold has taken the impression and been allowedjto set rnolten metal is introduced to'the mold andwerhave found that this step in the process can be most effectively performedand the relief faithfully reproduced in the metal without injuring the mold, by spraying the-surface of the mold witha finely divided spray ofmolten metal, using compressed air or the like -to atomize the metal and project, it evenly over the surface of the moldr -l In the accompanying'drawing" we have illustrated a specific application of our invention wherein our novel method of producing reliefs is employed for incorporating a metal relief in a structure such as the lid of a casket, cigarette humidor, or the like. In the drawing,

.Fig. 1 is a detail section view showing the swelled gelatin relief;

Fig. 2 illustrates the method of producing the plaster mold from the swelled gelatin;

Fig. 3 illustrates the formation of the medallion 10 in the lid of a cigarette box or the like; and

Fig. 4 illustratesthe finished medallion secured in the box lid. h

In employing our invention to make an artistic has-relief of a subject the first step consists in photographing either the subject itself or a picture of the subject to provide a light-permeable negative of special characteristics hereinafter described. Although the negative may be prepared by photographing the subject directly withlight- 20 ing and subsequent developing which produces thedesired characteristics, we prefer to prepare the negative by first preparing an ordinary positive photograph or'portrait of the subject and. then taking the negative photograph from the 25 positive.

As will appear, the relatively lighter areas in the subject or in the positive photograph of the subject, which will be the darker areas on the negative, represent the portions of the subject 30 which will be reproduced in'greate'r relief. For thatjreasonit is desirable, when preparing either the negative directly from the subject, or, as is preferable, when preparing the preliminary positive photograph or portrait, to employ lighting in which the prominent portions of the subject, such as the cheeks and nose of the face, arelighted more strongly than the depressed portions. The

reason for our preference in taking a preliminary positiveiphotograph and preparing the negative 40 from it, is because that method affords the opportunity of inspecting the picture and retouching it prior to making the negative. It is frequently necessary to lighten up the areas such as the eye- "brows and hair which may appear as darker areas 45 on the subject or positive photograph but which should constitute lighter areas on the positive to have prominence in the metal relief.

.When thenegative is finally prepared by either method'th'e relatively opaque areas in the negative. will represent the portions which will be reproduced in higher relief. The characteristics of the final negative will be the desireddistribution of lightand dark areas and a high gamma or contrast. 55

The colloid used to make the relief pattern is preferably one which will swell in the presence of water and may suitably consist of a 15% solution of soft gelatin. A plate is made from the colloid or gelatin by spreading the colloid on a glass plate using from 12 minims per square inch up, according to the height of the relief desired. In coating the plate with gelatin, care should be taken-to insure a-uniform thickness throughout and, after the coating operation, the gelatin covered plate is dried thoroughly. After drying, the plate is treated with a bath of alight sensitive tanning salt which may be prepared by adding one part potassium 'bichromate tosixteen parts of water and the resulting aqueous solution of the salt mixed with methyl alcohol in the proportion of one part aqueous salt solution to four parts methyl alcohol. Sodium or am-' monium bichromate may also be used in place of the potassium bichromate. The gelatin cove ered plate is immersed-in the resulting sensitizing bath for a period of from 5. to 15 minutes, according to the contrast desired,,-a longer immersion producing softeness and a shorter immersion giving contrast in the final relief. After immersion, the sensitized gelatin plate is removed and dried quickly by heat.

The gelatin plate is then ready for exposure, with the negative and for this purpose the negative is preferably superimposed on the gelatin coating and exposed to a powerful actinic light source, such as arc light or sunlight and after exposure for a suitable period of time, the gelatin plate is removed and washedv thoroughly in a number of changes of water.

'The next step in our processcomprises subjecting the exposed gelatin plate to .a swelling treatment to produce the relief in gelatin. This treatment will produce thelrelief because of the fact that swelling will take place in the portions of the gelatin which were adjacent the more opaque areas of the negative but will be restrained in the portions exposed to light.

We have found that an effective swelling bath may comprise a weak solution of a strong base and may be prepared by adding one .ounce of glycerine and one-quarter ounce ammonia (880) to 32 oz. Water. f

The gelatin plate should be immersed in the resultantswelling bath for a brief period, such asfor example ten minutes; approximately, and care shouldbe taken not to immerse the plate in the bath foran excessive period of time as that might result in reticulation of the gelatin.

-The gelatin plate; is then removed from the bath and rinsed quickly in cold water after which the surface moisture is removed. If plaster of Paris is to be used; to make the mold fromthe gelatin pattern, as is preferable, the pattern is then coated carefully with a thin coating of a suitable lubricating substance such as calcium stearate for thepurpose of reducing later adhesion between the gelatin and the plaster. The gelatin relief is now ready for use asa pattern .in making-the negative mold from which the metal, relief isprepared. r I I As stated above the material which 'we have found best adapted for taking an accurate and sharp negative impressionfrom the rather delicateggelatin relief pattern is plaster of Paris v which may be applied without injury to the gela- .tin pattern by coating'the pattern with a paste of plaster of Paris and water of about the consistency of heavy cream. 'In pouring the plaster of Paris paste on the gelatin relief, care should be taken to insure that no air bubbles are caught in the depressions of the relief.

When the plaster of Paris is set, it may be separated from the gelatin relief by the use of a sharp tool, such as a spatula, which, upon being inserted between the gelatin and the plaster of Paris, will break the seal between them and separate the cast and the gelatin quickly and cleanly as aided'by the stearate coating. Although plaster of Paris is the substance best adapted for producing a sharp negative mold, other substances which are also effective are pyroxylin with a suitable filler such as aluminum In the use of either of the latter substances, the preliminary stearate coating may be dispensed with.

The mold or cast is then ready for preparing the final metal relief and we have found that the most effective manner of introducing metal into'thev mold to producethe desired accuracy and sharpness in the metal image is to spray the mold with finely divided molten metal. The metal spraying apparatus which we use for this purpose employs an oxy-acetylene flame for melting the metal which is usually fed to the sprayer in the form of a wire. A moderate blast of compressed air or other suitable gas is used both to atomize the molten metal into a fine spray and to project the molten spray against the concave surfaceof the mold.

In spraying the mold a thin coating is first applied evenly over the entire molding surface and in forming the initial coating it is of importance that the sprayer be held in a position to direct the molten spray at right angles to the surface of the cast, the spray traversing the mold with an even slow stroke. After the initial coating has beenapplied the spraying is continued until a metal plaque or medallion of the desired thickness is obtained. Upon removal of the plaque from the cast or mold it will be found that a homogenous metal structure has been formed and that the bas-relief has been faithfully reproduced on the surface adjacent the mold. After spraying it will be found that the metal relief can be removed almost immediately as the cooling of the'rnetal takes place instantly upon the deposit of the atomized particles of molten metal on the: surface of the mold.

The preferred embodiment of our invention which has nowbeen described is subject to various modifications without departing from the spirit of our invention which is to be limited only as indicated in the appended claims. Thus it is obvious that intaglios may also be made by the use of our invention by substituting a light-permeable positive photograph for the negative used to make the relief. This positive may obviously be prepared in a number of ways which will readily present themselves to the skilled photographer and need not be described herein.

As a further refinement of our invention we have devised a novel method for incorporating a metal relief in another structure such as a box lid, cigarette humidor, casket, picture frame or the like.

Thus as indicated in Fig. 1, the swelled gelatin relief I is formed, as above, on a thin glass 'pared is then inserted in a suitable molding box Ill and the plaster of Paris 4 is poured over the coated gelatin to fill the box to the desired depth. After the plaster 4 has set, the mold is separated from the gelatin by the use of a spatula, or the like, and is ready for use to incorporate the metal relief in the lid 6 (Fig. 3) of a casket 5. The lid of the casket is prepared to receive the medallion by being cut away to provide an aperture 1 of approximately the shape of the medallion to be incorporated therein but slightly smaller than the medallion, the edges of the aperture being bevelled as indicated at 1. After the lid is thus prepared, the mold 4 is superimposed over the aperture 7 in the position indicated, leaving a small space 4 around the bevelled edge of the aperture and between it and the adjacent concavity of the mold. The mold is secured to the outside of the lid in any suitable manner.

A metal spraying apparatus 8, of the type above described, is then supported on the opposite side of the lid 6 from that on which the mold 4 is secured, and a blast of molten metal 9 is directed against the inside of the mold 4 to fill the mold concavity, including the space 4 thereof. This spraying operation is continued in the manner described above until a layer of metal projects slightly into the inside surface of the box lid, after which the plaster of Paris cast 4 is removed. The inner surface of the lid 6 may then be buffed down until a smooth, unbroken inner surface is presented and it will be found that the metal of the finished medallion comprises substantially an integral part of the metal of the lid, as indicated at 9 in Fig. 4, being secured therein by the adhesion of the metal as well as by the locking bevels 'l'.

I claim:

1. The method of producing relief images, intaglios and the like which comprises retouching a positive of the subject to lighten areas which are to be reproduced in relief and taking a lightpermeable negative photograph from the retouched positive, treating a gelatin plate with a light sensitive tanning salt, exposing the gelatin, so treated, to actinic light with the light-permeable photograph to tan the gelatin areas disposed opposite the less opaque areas of negative, treating the exposed gelatin with a weak basic solution to develop a relief pattern on the surface thereof by swelling the areas which were relatively less exposed to light and subsequently preparing a metal relief from the pattern so prepared.

2. The method of producing'a relief medallion and incorporating the same in a structure which comprises preparing a pattern of the subject, preparing a negative mold from the pattern, cutting an aperture in the structure at the position desired for the medallion, superimposing the negative mold over the aperture with its molding surface exposed through the aperture, applying a thin film of metal to the negative impression of the mold by spraying the same through the aperture with atomized molten metal and subsequently applying further layers of metal to build the medallion to the thickness desired and form a bond between the medallion and the structure.

GEORGE B. CUTTS. HAROLD JACKSON.

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