Show V PROCESS ENGRAVING In the older methods of producing en ena gravities gravIni on wood or copper or steel for re really good results the engraver must be to some extent an artist An engraving made entirely by hand haM has possibilities pos for good or bad that do donot donot donot not belong to the mechanical processes and a good wood or steel engraving has a character all its own that can be attained 8 in no other way In many respects it is aa aS individual as a paint aint ing Such engravings however are both rare and aDd expensive and it is prin principally principally principally because be au of or this thir and because of I 3 6 f I 3 I I I I I Small Portion of HalfTone Plate I Greatly Magnified I Showing gradations from dense shadow to high light J I the growing desire lesire for good copies of things that the various arious photo photographic photographic photographIc I graphic processes es have been developed f These processes moreover are arc very I rapid A picture that an engraver angra r would be weeks In doing by hand daft can l be produced in Iii a few hours and the photographic copy cop will be Infinitely o better bettor than a poor copy made by hand The process picture will be faithful photographically subject to the faults I of or the tho photograph but these faults can ba b avoided or neutralized to a 1 great extent by skillful handling both I in photographing the original and In I 1 the th subsequent treatment of the plate ie 1 There are aro so ao many marty processes proa es that It I is impossible to treat all of them in J A f I I I I I I I I f I l o the limits of this article But one will willbe be ba described therefore the one ne usual usually usually usually ly known as the halftone process It Itis Itis ItIs is the most common and aD 1 its products are the most familiar The process procesa plate is printed as ag type are ara printed the raised portions carry carrying ing lag the ink and making the impression sion In this respect it differs from the engraving Ying on steel or copper in which the ink Is carried in the cuts the raised sed portions being wiped clean Some Somo method had to be used there therefore therefore therefore fore which would produce a plate in which w the portions to be printed in would be left raised Moreover since sin every printed part is as black as every Other printed part cart the half halftones halftones tones rones must be made up of the right proportions of dead black and clear white The effect of a photographic negative or a print from such a nega negative n negative ga tive in ill which the tones are produced by different oen dentY ity of deposit cannot be e copied in printers Ink The effect is approximated by the use of a as screen seren s r n The HalfTone Screen Soreen This screen consists of a great num number number ber of lines ruled upon glass glaso Usually the Wg is ia such that the space be between beI between tween adjacent lir s is of the same s me width as ati each ch e line Une and the lines cross croes cro each enCh other at right angles More com corn complicated comI ed arrangements of men are aro sometimes used but they present little UttIe if it any advantage The ruling ia in pf Pt course e done one by machinery had and is then covered by another glass as aa a mechanical ical protection P against injury y Such an arrangement of or lines limes produces produce cu en curious curious rious effects Look at a street light through an umbrella or a handkerchief handkerchief chief 2nd ond it appears app ars to be he spread out in ma a kind of checked check d pattern This is isI not exactly the effect of the halftone screen 8 reen at aLl it is hi used in practice but It jt Itis itIs is somewhat similar The PM fineness of the ruling on the thel halftone h W screen is adjusted in accord accordance ance anito the she work to be b done A Api pi te which is to be printed primed with care enre caren careo n t n specIal paper may be made with a afine afine fine Ono screen lines to the inch or possibly even eTen finer than that The finer the screen the more perfect the tones which it produces produce For news newspaper newspaper paper work rk on the other hand where the printing must be done without great oot r at care are and on coarse paper per a n coarse oarse screen n must be used perhaps not moro more than fifty or Ot sixty lines Co tl the th inch mob A fine plate pinto would simply J fill ij up D with Ink In and none o ot lIft its fine gradations of tone show lio at all 1111 i iThe The Process In racking making the photograph the inal inai whatever it ma may be is very strongly t d either by arc a alights lights or by sunlight sunU bt so that all re ve reflections are avoided The Tho grating or 01 halftone screen is a 8 short distance e in front of the plate Dl te The effect can c n be I I varied by changing ch ng the but I the distance e must not be too great nor must the plate and aDd screen be in con eon contact tact The light forming foaming the tho image I I I which without the screen creen would pro I duce an ordinary negative n bends around the fine lines of the grating I and produces es a negative in which there thare are aro minute patches of light or clear spots and of ot dense deposit The light li t from a very ery bright Dright point in the object will wI bend so completely about the fine lines linea of the grating that their presence 1 S 1 nce Ja Is not at evident at all A loss leas bright point permits the of Sr the grating linen lines to show how as small dots blots which may be connected by fine lines or may not according to the th O brightness s Still StIn less Je light snows chews as I small imail circles opposite op ite the openings oI enl s in inthe the ther th screen and the size sl of these theae circles I depends also upon the brightness The cut rut shows the appearance very verJ greatly magnified of ot a portion of a print by b process The effect of such an ap appearance appe rance pe without magnification is a continuous gradation from dense black to 10 clear white When the negative has been obtained In this th way developed washed and dried the fihn Is placed in contact with witha a 8 5 plate of copper or zinc zinc e Small Portions of HalfTone Screens Greatly Magnified the copper for the finer lIner work under considerable pressure and exposed to sunlight aa in ordinary photographic printing After treatment the copper copperplate copperplate copperplate plate shows an coating at atthe atthe atthe the points which are finally to print black and aDd the space between these points 1 is clear The edges of the cop COD copper couper per plate are then varnished to protect them against the action of the acid and the plate fa is ready to be etched This Is ia done by rocking it in a bath of acid which eats eato e tn away the copper sur surface surface surface face wherever it ia Is unprotected and leaves the parts which are covered with the deposit raised to the original level These raised parts ii thua take tahe he the ink from the roller and print black The plate is te removed from the acid add occasionally occa if the etching Is long king continued to test it and to protect the small smaIl raised points from undercutting by the add acid The general genen fault faitH of a halftone half tone plate as aa it t comes from the acid bath Is a alack alack alack lack of o of vitality or contrast a slight alight muddiness of tone or abruptness n at atthe atthe atthe the edges This can ean be remedied in either of two ways both of them hand handwork handwork handwork work Further etching can be carried earned on in any desired parts by the use of the acid brush diminishing the size of oC the tha minute copper points and thus fuus clearing up the high lights or soften softening ing lag the edges The second method is the use oC or the regular gravers tools toots cutting the tim surface of the plate In lines of greater or less regularity to obtain the desired gradations of tone in the different parts These engraved lines are of course quite evident in inthe inthe Inthe the print This method in the hands of a skIllful engraver produces the most artistic effects The best results are seen on the pages of magazines of I the tho higher class cleas |