CELLOPHANE ROLL FILMS for SLIDE LANTERNS' ROSS BONAR, FLOYD BONAR,
AND
EARL C. H. DAVIESI
West Virginia University, Morgantown, West Virginia
A cellophane rollfilm of standard width for slide lanterns may be quickly made from thin commercial wrapping cellophane by the use of carbon paper typing or by pen drawings. A roll of cellophane of 0.001 inch thickness and 400 inches long, wound on a 8/la-inchcore i s less than 3/4 inch in diameter. Such a roll i s equivalent to 120 slides, with a capacity for at least 8000 words, yet weighs less than one glass slide. These rolls are inserted in and operated by a n easily constructed roll carrier which fits into the opening occupied by the slide carrier of the ordinary lantern. . Carbon paper impressions on cellophane smear easily. Such typing may be made more permanent by pessing the typed film through a suitable liquid, such as ethyl acetate, followed by blotting and drying.
core the roll is less than 3 / r of an inch in diameter, yet is equivalent to about 120 slides, with a capacity of from 8000 to 10,000 single spaced typewritten words (from eight to ten pages of THISJOURNAL).Yet, a roll of this size weighs less than one glass slide.
ROLL-FILM CARRIER The essential materials needed for the construction of the roll-film carrier consist of a thin sheet of brass, aluminum, cardboard, or other suitable material, and a smooth 3/16-inch rod of brass, glass, or other substance. Details of construction of one form of roll carrier are shown to scale in Figures 1 to 5. If desired the frame may be made long enough to contain a section for slides, which may be used to supplement the roll film by merely inserting the slide and pushing the carrier a few inches ++++++ to one side. HE use of cellophane as a convenient material A very simple carrier may be made by cutting a for making lantern slides has been described by frame from the bottom of a cardboard box and binding Wilson.' Howit together with adever, t h e a u t h o r s hesive tape. Glass have found that the rods will serve as thinness of the or& rollers and corks nary sheet of celloplaced on the film phane makes possible rollers inside t h e its use as roll films of frame will both serve considerable length, "h as film guides and operated by a simply K d prevent sidewise slipconstructed roll carping of t h e rollers. A bit of saliva may rier which replaces the slide carrier in be used to stick the .-------.---.---------the ordinam lantern. end of the film to This change is the Fm.2 fie3 the glass rollers. The St,* End view only adjustment necsaliva should be apshowin Slide Fr6 1 c0fEhfwF ~ I ~ plied to the roller essary and requires ~ b y d of ~~~e Rollers but a few seconds. and the lilm pressed The capacity of the I p o t ?OF mm I against it. LI I film carrier shown in Fr6. 4n l m gu;2e.-4.0part--/l PREPARATION OF THE Figures 1-6 is a film FILM of cellophane 400 F ; I ~R O I I ~ ~ inches long, 4 inches As generally sold, wide, and 0.001 inch D I I I I I I I I I wrapping cellophane a L thick. When wound f,a 5 scde is about 0.001 inch Guyde Roller closely on a 3/ls-inch thick and is in rolls * Contribution No. 88 of the Division of Industrial Sciences of Buckhannon, West Virginia; FLOYD BONAR, physics departTHE
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West Virginia University. Presented by Earl C. H. Danes before the Division of Chemical Education of the American Chemical Soeiety at Denver, Colorado, August, 1932. i Ross BONAR,principal, Buckhannon Junior High School,
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ment, Washington Irving High School, Clarksburg, West Virginia; EARLC. H. DAVIES,plofesso, of physicnl chemistry, West Virginia University, Morgantown, West Virginia. J. L. WILSON,"Lantern slides from cellophane." J. CHEM. Eouc., 8, 221S3 (Nav., 1931).
about 20 These rolls mav be cut to the ~- inches wide. proper width by a slight sawing motion of a sharp knife. Jagged edges should be avoided, since they are apt to start tears in the film. Cellophane is quite tough, but tearing, once.started, proceeds easily and noiselessly. Cellophane which has been moisture-proofed by a thin transparent coating does not take ink readily and will not take the treatment described later for "fixing" carbon typing. Untreated cellophane may be easily detected, since it softens readily in water. Typing on cellophane requires the use of carbon paper for satisfactory legibility, since the ribbon does not give a sufficiently heavy impression. Tests made with a variety of carbon papers showed better results with those of soft finish, such as are used for noiseless typewriters. When typing, a heavier impression is obtained by using strips of carbon paper on both sides of the cellophane, although one strip is fairly satisfactory. When only one strip is used i t should be placed on top of the cellophane, thereby making the writing visible to the typist. Errors in typing may be easily erased by use of a clean cloth. ~~~~~~~
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FIGURE &-ROLL Fnu CARRIER Attachment assembled and threaded with film.
Cellophane takes pen work quite readily. This is best done after the film is threaded into the carrier. A piece of cardboard may be inserted under the guide rollers to support the film. Graph paper placed over the cardboard will aid in uniform lettering and lining. Of several inks tried, i t was found that for dark, sharp lines black India ink is best, while for colored drawings the transparent inks are better than those which contain opaque, colored pigments. For fine, sharp lines an extra fine pen, such as the crow quill steel pen, is desirable. Wrinkles in the film caused by the ink will scarcely be noticeable on the screen. Ink drawings on cellophane need no "fixing" process to make them permanent. Water-soluble inks are difficult to remove from cellophane. Black India ink may be removed by a soft cloth while still wet, or with a cloth moistened with ethyl acetate after drying. Pen scratches cannot be removed. Drawings may be original or traced from pictures, graphs, or charts placed beneath the transparent film. If many repetitions of the same design are needed, a rubber stamp, stencil, or type may be used.
FIXING CARBON PAPER WRITING
Carbon typing on cellophane readily smears. If permanency is desired i t should be further treated. A satisfactory procedure consists of passing the typed film through a suitable liquid and carefully blotting it between unglazed paper while i t is moist, care being taken that the blotting paper does not slide over the wet surface. The paper removes most of the liquid and excess ink. The film is then placed between dry paper and pressed for several minutes to complete the "fixing." Of fifty chemicals tried, the most satisfactory for the purpose are: amyl acetate, ethyl acetate, methyl acetate, acetaldehyde, benzyl alcohol, isoamyl alcohol, a mixture of 75 per cent. diethyl ether and 25 per cent. ethyl alcohol. Films treated with these were wound and rewound as much as 200 times and still showed no signs of smearing, while untreated carbon typing starts to smear with the first winding. The fixing reaction seems to be somewhat as follows. Before the treatment, little flakes of carbon ink constitute the face of each t w e d letter. The fixing bath begins to dissolve these a i d causes increased p&etration or adhesion, because the dye substance or the vehicle in the carbon ink is soluble in the fixing liquid. If the printing on the cellophane is blotted while wet with the solvent and soon after treatment, the excess flakes which would cause smearing are either removed or made to adhere more tightly to the film, while if allowed to dry without blotting the ink dissolves and runs, giving color streaks. Printing, stenciling, or writing with inks which give no flaky particles should not smear. OPERATING THE ROLL FILM AND CARRIER
A few suggestions concerning the threading and operating of the roll film and carrier should prove valuable. If slots are provided in the film rollers, the cellophane is threaded in much the same manner as a kodak film; if not, a bit of glue or saliva should be rubbed along the roller and the end of the cellophane touched to it. Straight and smooth threading of the ends of the film is important, for upon this depends, in a large degree, the smooth winding of the film. Fresh cellophane surfaces tend to be sticky when pressed together. Therefore, in winding the film i t is better to wind it loosely a t first, guiding it carefully onto the roller, and later tightening it by turning the roller on which i t is being wound. After the other end is threaded, running the film back and forth a few times will make i t wind more compactly and smoothly. Under no circumstances should much force be used in tightening the roll of film, for creases will be pressed into it. Once wound, the cellophane film tends to set itself to the roll and winds more readily thereafter. If reasonable care is taken, tearing of the films should be rare. Tom films may be readily mended with transparent library tape, glue, or temporarily with saliva. There is little danger of cellophane being
ignited in the ordinary lantern. A tightly wound roll of 6lm will scarcely hum. Buckling of the film by heat should give little trouble, especially if the film is kept taut. USES
The cellophane roll film is especially useful for lectures which involve graphs, maps, mathematical equations, chemical reactions, and structural formulas, particularly those used in organic chemistry. Complicated diagrams of apparatus and biological specimens may be drawn in colors and preserved, whereas the usual chalk drawings must he erased. Artistic talent among the students may be preserved for the school after the artist is gone. Film-making projects in school clubs may be employed for illustrating a particular piece of literature or science topic, or for original caricatures and comic strips. From fifty to one hundred songs may be typed on a 400-inch roll, or the music and words may be penned on the film.
The cellophane roll film has several advantages over the various types of still projection now in use and should prove a valuable supplement to them. For typed or penned material its larger surface gives it a distinct advantage over "strip films" in that photographic transfer is not necessary, more material may be placed on corresponding lengths, and the projecting conditions need not he different from those of the ordinary slide. No extra lens system or costly alteration of the projection lantern is required. The slide carrier is merely withdrawn and the roll carrier inserted. Compared to the slide, the cellophane roll is extremely compact and light, and when once made there is no subsequent mixing of the slides. Furthermore, the film may be quickly turned from one section to another or slowly and continuously turned as desired. The cellophane roll film lends itself readily to home-made production and at a cost far less than the glass slide.
