74 



THE INDIA RUBBER WORLD 



[November 1, 1919. 



machines without the aid of primer's type offers one drawback 

 which is very noticeable, and that is the unevenness with which 

 the lines end. The reason for that, however, is that the text 

 is typewritten on ordinary typewfiters, and then photographed. 

 The lines end, therefore, as all typewritten matter ends, very 

 irregularly. The experimental departments of all the greater 

 typewriter companies are now 



hard at work seeking a way to 

 tiiake lines end evenly, and one of these days American in- 

 genuity will solve the problem. Offset work will then find new 

 fields of usefulness which it has up to now been quite unable 

 to enter with any notable success. 



Offset work is cheaper than ordinary typographical work, and 

 can be turned out more rapidly. One of the reasons for greater 

 economy is the difference in the time necessary for the make- 

 ready. In ordinary typographical work the make-ready fre- 

 quently takes up hours. In offset work that which takes the place 

 of the make-ready requires an almost negligible amount of time, 

 with a corresponding saving of money. 



There are four stages in the execution of the work which can 



be described so that the reader will fully understand the process. 



l._The text, which has been carefully typewritten on new 



machines to insure equal pressure of each letter on the paper and 



to guarantee perfect alinement, is photographed. 



2.— An ordinary zinc line plate is made from the photographii 

 glass negative thus obtained, the negative image being reversed 

 to a positive iirage in the course of the transfer after the cus- 

 tomary manner of photographic process work. 



3._The zinc plate, ordinarily with several others, is arranged 

 in a form as usual and put in the press, where it is inked in the 

 customary manner by rollers, and an ink impression of the plate 

 IS transferred to a rubber covered metal cylinder, this impression 

 being negative in the sense that the type is reversed left for 

 right and reads backwards. 



4._The operation of the press is so timed and arranged that 

 a sheet of paper is then fed through it and the ink impression 

 transferred by direct contact from the rubber blanket on the 

 cylinder to the surface of the paper, where it becomes a positive 

 impression reading from left to right. 



After use, the rubber-covered cylinder is very easily cleaned, 

 and the surface can be used again and again, until the rubber is 

 worn out. The rubber blanket may last less than a month or over 

 two months, depending on the amount of work done, and partic- 

 ularly on the kind of stock used. Coarse, hard paper will natural- 

 ly wear out the rubber sheet quicker than other kinds of stock. 



When black ink is used, from 3000 to 4000 copies per hour can be 

 run off a good machine. Color work is naturally done much 

 more slowly. The ink used for offset work dries very quickly, 

 and the stock, as already mentioned, is never dampened, so that 

 the sheets coming off the press can be almost immediately folded 

 into booklets, books, etc., and be delivered to the customer. 

 Sheets coming off typographical presses must be allowed to dry 

 for a considerable while before they can be folded or handled in 

 any way. 



The machines used to-day for offset work are not perfect, but 

 manufacturers will now doubtless feel encouraged to remedy de- 

 fects. The largely increased fields of sale now opening up offer 

 possibilities of augmented profits sufficient to warrant con- 

 siderable effort at improvements. 



Rubber men will probably be interested in a few remarks on 

 the rubber covering for the rollers, with which we will end our 

 story. 



The thickness and the degree of elasticity of the rubber blanket 

 covering the cylinder are features that have demanded many and 

 long-continued experiments. The entire blanket must be of abso- 

 lutely uniform thickness, as the slightest defect in its uniformity 

 renders the whole unfit for use. 



The best printer's blanket for offset work has always been im- 

 ported from Europe. Before the war, the best blanket, in small 

 sizes, was made in Germany, but the Germans were utterly un- 



able to succeed in the larger sizes, in which Great Britain has 

 achieved preeminence, producing extremely fine printer's blankets 

 up to 70 inches and even more in width. Before the war these im- 

 ported blankets sold in the United States at $4 a square yard. The 

 price varies these days considerably but is, of course, much higher. 



The expansion of offset printing in tropical and subtropical 

 countries depends largely on the rubber chemist. Printer's 

 blankets that give good results in New York or London may not 

 give satisfaction in very hot or damp countries. These sensitive 

 rubber blankets suffer from high temperatures combined with 

 great atmospheric moisture. 



Here is an interesting and lucrative field for the American 

 rubber industry. 



INTERESTING LETTERS FROM OUR READERS. 

 DESIRES TO SUPPLY ZINC SULPHIDE TO THE TRADE. 



To THE Editor of The India Rubber World: 



DE.\R SIR:— A few days ago I was showing a sample of 

 zinc sulphide to a subscriber to your magazine and a 

 manufacturer of rubber goods. He was not using zinc sulphide 

 himself but claimed that it is peculiarly adaptable to use in the 

 rubljer trade in the manufacture of particularly white goods, due 

 to sulphur from, the sulphide in some way reacting with the 

 rubber. 



We looked through a recent number of the magazine to find a 

 quotation on zinc sulphide, which, he said, was formerly listed 

 there. He then suggested my addressing you as the best author- 

 ity on the wholesale market for zinc sulphide and as to who are 

 using zinc sulphide now. 



I hope that you may be able to furnish me this information, 

 for I have a small plant for making pure zinc oxide in hundred- 

 pound lots that can be immediately turned into a zinc sulphide 

 plant, and can expand to a large plant should I find a large field 

 for the product. This information would be most timely to 

 me. and if there is a demand for zinc sulphide, will also be of 

 value to your advertisers. 



.^waiting this information and a reply from you, I am, 

 Yours most sincerely, 



Samuel T. H.\lsted. 



163 Rubidoux avenue. Riverside, California. 



SEASONS' SUPPLIES OF FICUS RUBBER. 



To THE Editor of The India Rubber World: 



DEAR SIR:— I would ask you to be so kind as to bring me 

 in touch with a solid American factory (no dealers) which 

 is willing to buy Ficus rubber in seasons' supplies of from 10,000 to 

 30,000 pounds. A sample of the same I will send for their p- 

 proval the moment I receive the address. Only few estates in 

 .lava produce Ficus rubber, most of them cultivate Hevea 

 brasilicnsis. so there is here practically no market for this sort of 

 rubber. Thanking you in anticipation. 



Yours very respectfully, 



J. Reints Bok. 

 Soerabaya. F. M. .S. 



RUBBER GOODS FOR AUSTRIA AND SERBIA. 



William Ford Upson has been appointed Trade Commissioner 

 to Vienna by the Bureau of Foreign and Domestic Commerce, 

 and at an early date will proceed to his post to conduct an inves- 

 tigation of general commercial and economic conditions in 

 Austria and Serbia. Mr. Upson was an officer of the American 

 Red Cross during the war and later the .\merican delegate to the 

 Inter-Allied Trade Commission at Vienna and is well informed 

 regarding conditions there. Among the many things needed by 

 Austria and Serbia which, in his opinion, America can best sup- 

 ply, are rubber goods, footwear, clothing, cotton oils and fats, 

 petroleum and its products. American capital and business 

 acumen along broad constructive lines will be required to estab- 

 lish business relations. 



