Jan . 1923 I L L U M I N A T I O N I T E M S 6 3

requiring the 14-volt tap. The three taps allow a variation of voltage so that the transformer can be used to operate electric toys thereby enlarging its scope of usefulness beyond the Christmas season.

A complete outfit is available consisting of the trans-former with 10-foot lead and plug for attaching to a convenience outlet or lamp socket, 43 feet of cord with

A S T E P - D O W N T R A N S F O R M E R F O R U S E I N B U R N I N G C H R I S T M A S T R E E L A M P S I N M U L T I P L E

17 sockets attached, and eighteen 14-volt Mazda lamps, one lamp being a spare, all packed in a distinctive holiday box.

The 10-foot lead permits the transformer to be concealed beneath the tree. The cord which carries the sockets is divided into branches in sets of four at 15-inch intervals allowing adequate distribution of the lamps to all parts of the tree. The lamps are the regular Mazda Christmas tree lamps, and are sup-plied in red, blue, green, orange, and frosted white.

T H I S P H A N T O M V I E W S H O W S H O W T H E W I R I N G OF T H E C H R I S T M A S T R E E L I G H T I N G S E T P E R M I T S T H E L A M P S TO B E

D I S T R I B U T E D TO A L L P A R T S OF T H E T R E E

COLOR MATCHING U N I T S IN T H E I N D U S T R I E S

It is the opinion of a great many persons acquainted generally" with color matching units that these units find their greatest field of application in commercial estab-lishments. While it is true that these units, when first introduced about eight years ago, found immediate favor for color matching purposes in many department stores, haberdashery shops, millinery shops and furriers, it is nevertheless true that these units have their widest

-application today in locations commonly classed as industrial. To be convinced of this fact, and to obtain a greater appreciation, perhaps, of the possibilities of color matching units from the various standpoints of

service to industry, to science, to the arts, etc., one need only examine a classified list of present-day users of these units:—

Art Schools Museums and Galleries Banks Cigar Stores and Factories Clothing Manufacturers Coffee Roasting Rooms Dentists and Dental Supply Manu-

facturers Department and Dry Goods Stores Dyers and Cleaners Food Products Furriers Grain Elevators and Mills Hospitals Industrial and Manufacturing

Plants

Jewelers Laboratories Leather Manufacturing Plants Men's Furnishers Tailors and Haberdashers Milliners Paint, Color and Dye Works Paper Mills Printers and Lithographers Rubber Manufacturing Plants Schools and Colleges Seed Companies Shoe Manufacturers Sugar Refineries Textile Mills Wall Paper Companies

I t will be seen from this list that the field for the advantageous use of these units is wide indeed, and additional uses for them are being discovered, literally, almost every day. Viewed from a strictly engineering standpoint, however, we may say there are at present six clearly defined classes of industrial operations where the color matching unit can not only be used to a good advantage, but where its use is almost necessary. These are as follows:

Lithographing Cotton Grading Cigar Grading

Leather Grading Dyeing Paint and Chemical Examination

In lithographic printing and in the preparation of lithographic stones for the printing process, the color of the light used for artificial illumination plays a very important part. A large part of lithographing printing is color work, and since the appearance of a given color varies with the quality of light thrown upon it, it is quite essential that in this industry light be used which will show the colors as they appear in daylight. A general system of noon sunlight illumination is also very desirable in the art department. Here, again, over individual desks where accurate color discrimina-tion is essential, north sky daylight units are desirable. For general illumination over the presses, noon sun-light units are to be recommended, one or two units over each press. At those points in the press room where the colors of the finished product are examined and checked, north sky daylight units should be in-stalled. Two well known publishing concerns using artificial daylight units are the Curtis Publishing Co., Philadelphia, which has about 75 north sky daylight units installed near color presses for checking colors, and the Crowell Publishing Co., Springfield, Ohio, where the general illumination of the press room is supplied by about 300 noon sunlight units. Another installation is that in the Bureau of Engraving and Printing, Treasury Department, at Washington, D. C. Several hundred units are used there for general illumination, which are supplemented by many local units of the design shown in Fig. 1 over engravers' benches and tables and at other points where special operations are carried on which require accurate color discrimination.

64 I L L U M I N A T I O N I T E M S Journal Α. L E . E .

For the mixing of inks and for other cases where accurate color matching or comparisons are desired, north sky daylight units are recommended. Either pendant units of the type shown in Fig. 1, or angle units having a similar color correcting screen, are used; whether the surfaces illuminated are located in a hori-zontal or in a vertical plane in most cases, governs the choice of the type of unit.

In practically every large cotton mill, a room is devoted entirely to classifying by tints the cotton which is to be purchased for the mill's use. Likewise, a

F I G . 1—A U N I T W H I C H S U P P L I E S N O R T H S K Y D A Y L I G H T

I L L U M I N A T I O N . D E S I G N E D E S P E C I A L L Y F O R L O C A L I Z E D L I G H T -

I N G W H E R E P R E C I S I O N I N C O L O R M A T C H I N G , G R A D I N G , I N -

S P E C T I O N , E T C . , is R E Q U I R E D .

accurately pairs of socks as to color, in order that any slight color differences resulting from the dyeing pro-cess will not be noticeable in any one pair.

A great many cigar factories have installed color matching units over the benches where their tobacco inspectors work. North sky daylight units are em-ployed, hung a few feet above the level of the work. Best practise requires one unit for each inspector; if there are many inspectors working side by side along the bench as is usually the case, a unit which takes a 150 or 200-watt Mazda C lamp, will be found satis-factory. This arrangement allows easy, accurate classification by color, not only of the tobacco leaves that are to be used in the manufacture of the different grades of cigars, but also of the finished cigars for separating them into grades according to their color, for packing purposes.

The process of leather grading is also facilitated by the use of these units. In the matching of hides and of finished pieces of leather particularly, it is again necessary to guard against the presence of surface sheen.

color grading space is imperative in the office of every big cotton buyer and cotton broker. The Bureau of Standards furnishes the standards by which cotton is graded as to tint. Both the primary standards and the secondary or consumer' standards were selected under true north sky daylight conditions. Obviously, if cotton is to be classified by tint with the aid of the standardized ''matching samples", correct results can be obtained only when the operation is carried on under north sky daylight itself or its substitute. North sky daylight units give very satisfactory results in this service. Care must be taken, however, to avoid sur-

F I G . 3 — I N S T A L L A T I O N O F C O L O R M A T C H I N G U N I T S I N

E N G R A V I N G D E P A R T M E N T O F L I T H O G R A P H I N G P L A N T . O N E

U N I T W I T H 5 0 0 - W A T T L A M P I N S T A L L E D O V E R E A C H D E S K .

T H E O R I G I N A L S Y S T E M O F G A S L A M P S IS S T I L L I N E V I D E N C E

F I G . 2 — A U N I T W H I C H S U P P L I E D N O O N S U N L I G H T I L L U M I N A -

T I O N . D E S I G N E D E S P E C I A L L Y F O R G E N E R A L L I G H T I N G W H E R E

D A Y L I G H T Q U A L I T Y I S R E Q U I R E D T H R O U G H O U T A N E N T I R E

R O O M OR A R E A .

face sheen on the individual strands of the cotton, which may be so great as to give an erroneous impression of its color even though examined under the accurate north sky daylight of the color matching unit. The same problem is presented in the inspection of deep pile silks, velvets, plushes, etc. But in all such cases where the units are properly installed and used, ideal results are obtained.

One of the largest hosiery mills in the country uses color matching units (500-watt units on five-foot centers along the benches) to grade yarns and to match

Color matching units are very desirable and practi-cally a necessity in all high grade dyeing establishments and in certain parts of all plants where fine dyeing is done. They allow accurate duplication of the colors of samples in the minimum length of time. North sky daylight units should be used in the drying rooms and other parts of these establishments where fine discrimination between color tints is imperative.

Most paint manufacturers maintain a laboratory for inspecting and testing the various paints they make. Usually, thin slabs of wood are painted over with the different paints and the colors of these slabs carefully checked. Illumination which will allow accurate color comparison and grouping is very desirable in such locations. Many chemical laboratories, also, require illumination under which slight color changes or the exact color of a precipitation may be noted. The illumination received from color matching units makes it possible to carry on these experiments continuously and accurately.