570 



PRINTING, PROGRESS OF, IN RECENT YEARS. 



covery, it was made adaptable to lithographic 

 work, the method being termed aluminography, 

 or alumography, or sometimes algraphy. In or- 

 der to get the needed porosity, the method is to 

 take a sheet of very pure rolled aluminum, and 

 grind off the surface that has been hardened by 

 the rolling, thus getting at the porous interior, 

 which is very similar in its properties to the 

 lithographic stone. Another method is to form 

 an aluminum surface by electrodeposition. The 

 aluminum plate has the advantage over the stone 

 of lightness, of requiring very much less space for 

 storage, and of being available for longer runs 

 without reproducing the design. The lithographic 

 stone is so cumbersome that the storing is an 

 item of importance, as a large lithographic house 

 has to handle a vast number of stones. The alu- 

 minum plates occupy only one-fiftieth the space 

 and are one-one-hundredth the weight of the 

 stone. The cost of the metal is but 38 cents a 

 pound, and a pound gives a very large surface. 

 Bulk for bulk, it is cheaper than brass. The sheets 

 used are only about a thirty-second of an inch 

 in thickness, and they can be drawn upon, trans- 

 ferred to, and manipulated generally as is the 

 stone. The plates are etched by phosphoric acid 

 to prevent the ink from spreading beyond the 

 limits of the design, and may be cleaned off after 

 using by a preparation of nitric acid. The fact 

 that aluminum is almost non-corrodable is one 

 of the largest elements in the success that has 

 attended the use of the metal in lithography. The 

 flexibility of the plate adapts it naturally to ro- 

 tary printing, and the Hoes, Huber, Scott, Alumi- 

 num Press and Plate Company, and others have 

 built special printing-machines to accommodate 

 them. The Scott flat-bed lithographic machine 

 handles either the stone or the aluminum plate; 

 the others are f.or aluminum plates only. These 

 machines are replacing former lithographic presses 

 with considerable rapidity, though the majority 

 of lithographic work is still done from stone. 



The trade is indebted largely for the adapta- 

 tion of aluminum in this way to Joseph Scholz, 

 of Mayence, and the Strecker-Scholz process of 

 preparing the plates is much used in the United 

 States, though the Huber Press Company has a 

 special method, and the Aluminum Press and 

 Plate Company also has a method based on the 

 Mullaly patents. 



Printing from Zinc. The use of zinc for 

 lithographic printing gave us the word zincog- 

 raphy, but that process was generally considered 

 a complete failure. However, the American Litho- 

 graphic Company did not give up experimenting 

 with this metal, and in 1899 several gentlemen 

 connected with that concern took out a series 

 of patents on a zinc plate obtained by electro- 

 depositing the zinc on another metal surface, as 

 copper. One of the reasons why aluminum proved 

 a good material is that it is obtained by electro- 

 deposition in the manufacture. Zinc deposited in 

 the same way constitutes a good material for 

 lithographic work, though it is more corrodable 

 than aluminum. The new method of handling 

 the zinc provides for depositing it on tubes that 

 are slipped on and off the cylinders of the print- 

 ing-press. The process is being used with con- 

 siderable success. 



Patent Blankets. The earlier forms of print- 

 ing-machines all employed a soft surface or 

 packing between the hard material of the press 

 proper and the tympan, on which to make the 

 impression of the type. Without such a soft 

 surface the weak machines used prior to 1830 

 would not have been able to produce enough pres- 

 sure of the paper against the type to print prop- 



erly. As stronger and heavier presses were manu- 

 factured, there was a tendency to use harder 

 printing surfaces, and what is known as hard 

 packing was generally substituted for the rub- 

 ber or felt blankets that were absolutely neces- 

 sary to early printing. The process of change 

 was gradual. At first a few thicknesses of paper 

 were placed over the rubber, then hard card- 

 board, then the rubber was discarded, and finally 

 the trade came to using the hardest cardboard it 

 could get, and putting very little of that between 

 the iron and the type, in the endeavor to secure 

 an unyielding surface. Because of these changs 

 pictorial printing reached a higher plane of de- 

 velopment, and the overlaying of illustrations be- 

 came a fine art, the lights and shades of the wood- 

 cuts or photoengraved plates being brought out 

 by very delicately cut and pasted thicknesses of 

 tissue-paper. 



Within a few years a tendency to return to 

 softer surfaces for printing has been manifested, 

 as illustrated printed matter has increased so fast 

 that the expense of overlaying the forms for 

 printing constituted a serious item of expense. 

 In the endeavor to get rid of this costly labor 

 different styles of wire spring blankets have been 

 introduced, and also corrugated rubber blankets, 

 to be used on the surface of printing cylinders and 

 on platens, surmounted by a sheet of thin cellu- 

 loid or very hard cardboard. Severy, Allen, and 

 Rhodes have each taken out patents in this field, 

 and introduced springy blankets that are adapted 

 to certain classes of work. The yielding of the 

 springs or rubber takes up a part of the irregu- 

 larities of the plates or cuts in the form, and re- 

 duces the necessity for " make-ready." 



The opponents of this new spring-blanket the- 

 ory assert that there is a loss in effect in the 

 heavy shadows of fine illustrations, and that if 

 the quality is reduced at the same time as the 

 cost, one might as well go back to the old-fash- 

 ioned rubber blanket, which, when covered with 

 hard cardboard, produced pretty good printing 

 with little " make-ready." 



Mechanical Overlays. Other innovations 

 looking to the saving of labor in overlaying con- 

 sist in mechanically produced overlays. The Ditt- 

 man, De Vinne-Bierstadt, and Humphrey & Up- 

 ham processes have each attracted much atten- 

 tion within a year or two. Dittman takes a 

 print on paper with full inking, dusts it with com- 

 mon flour, lets the flour that adheres swell with 

 the moisture of the printing-ink, and then bakes 

 the sheet to toughen it. The swelling exaggerates 

 the dark parts of the print, and, when the sheet 

 is pasted on the printing surface, serves to bring 

 up the darker portions of an illustration to ad- 

 vantage. The De Vinne-Bierstadt method is based 

 on the swelled gelatin process of the photoen- 

 graver. A print is taken on a thin sheet of trans- 

 parent celluloid and dusted with plumbago to 

 thicken the lines. This is then exposed in a pho- 

 tographer's printing-frame over a film of gelatin, 

 which is afterward swelled in the parts not made 

 insoluble by the light. From the gelatin -a plas- 

 ter-of-Paris mold is made, and from this a flexi- 

 ble reverse in gutta-percha. The gutta-percha is 

 backed with paper and becomes the overlay, being 

 thickest in the dark parts of the illustration. The 

 Humphrey & Upham method is adapted only to 

 duplicating overlays. The original overlay is cut 

 by hand in reverse, and from this a gutta-percha 

 impression is taken that becomes the overlay. All 

 these overlays are in use, but no one of them is 

 at this date used extensively. 



Illustrating and Engraving. Wood-engrav- 

 ing was the common method of producing illus- 



