COST

Fig. 37Figure 37. A Map of the Fenland by Prof. Yapp.(New Phytologist, 1908, Vol. 7)

(New Phytologist, 1908, Vol. 7)

GRAPHS OR CURVES.Simple though it be, the plotting of a curve for reproduction requires thought and care. In the first instance, the curve is drawn on squared paper, and the question naturally arises—To what extent are the squares to be represented? If it be desired to reproduce all the lines, say the paper is ruled in millimetres, a half-tone may be employed, or all these lines can be ruled over in black ink where the reproduction by line block is possible. It is, however, seldom necessary to represent all the smallest squares; it will generally be found that the centimetre squares are sufficient. If the original be plotted on paper which is ruled in pale blue, it can be reproduced by line block without re-drawing, since the blue will photograph as white with the plates commonly used; all the essential lines and curves must, of course, be in black. If, however, the rulings of the squared paper are in red, yellow, or dark blue, a tracing must be made. The horizontal and vertical sides should be ruled with a broad black line, but the internal intersectinglines should be much thinner. The actual curve may be in a continuous line if one only be shewn on the graph; if more are drawn, then each must be different, the obvious variations beingthe thick continuous line——,the thin continuous line ————,dashes either thick or thin— — —, or —— —— ——,dots · · · · · · ·,and finally combinations of dots and dashes — · — · — ·

Owing to the difficulty which some experience in drawing freehand a continuous line, the plot should be made twice the linear size of the intended reproduction. A good rule to follow in drawing lines is to keep the eye fixed on the point where the line is to end, the hand will then guide the pen in the right path, especially after a little practice. In many cases the ruler may be used, not only for straight but also for curved lines, for good curve rules may be purchased.

In order that the figure may look neat, the lines should be of an even thickness throughout their length; this is easily accomplished by means of a ruling pen.

It has been stated above that Bristol board is the best material to use for the making of drawings for line blocks; other materials may, however, be employed, although they are not so nice to work upon.

For instance, it may be necessary to reproduce a map; this, as has already been mentioned, may be conveniently done by pinning over the map a sheet of pale blue tracing linen, and tracing the map on this with Indian ink. The fact that the linen is blue does not matter, for it will photograph as if it were white.

Then again, many subjects may be of so complicated a nature as to be beyond the skill of the author to draw. In such a case a good plan is to take a photograph of the object and make a positive on smooth bromide paper, which need only be developed sufficiently far to give a print which just shows the features. The print, whendry, can then be worked on with fixed Indian ink. The finished drawing, when quite dry, may be immersed in any solution which will dissolve out the silver; a solution of iodine in potassium iodide answers sufficiently well. The print will turn very dark, but it must be allowed to remain in the bath until all the silver has dissolved; it is then removed, rinsed under the tap and placed in an ordinary fixing bath of hyposulphite of soda. All the colouration will be quickly removed so that the ink drawing will stand out well against the white paper. All that it now requires is a thorough washing in water; when dry it may be touched up and then placed under pressure in order to make it quite flat.*

*The chief disadvantage of iodine solution is its slowness of action; the following methods are much quicker.

(a) To a solution of 4 oz. of hyposulphite of soda in one pint of water, add a 10 per cent. aqueous solution of potassium ferricyanide until the mixture is lemon coloured. When the silver image has quite disappeared, wash the print thoroughly in water. Since the mixture does not keep, the ferricyanide solution should be added to the hyposulphite solution immediately before use.

(b) Mix 125 ccs. of a 10 per cent. alcoholic solution of iodine with 21 ccs. of a 10 per cent. aqueous solution of potassium cyanide, add to the mixture 1 litre of water. When the image has disappeared, which will be in less than a minute, wash for five minutes in water and dry.

This method of drawing over photographic prints will often save a considerable amount of time. For instance, it may be desired to reproduce a consecutive series of drawings to illustrate the microscopic structure of the subject. The ordinary way of doing this is to make camera lucida drawings of the sections, which is a lengthy and tiresome process; a photograph of each section will take much less time and will give quite as good results.

Before sending any line drawings to press they should be carefully examined; pencil marks may be rubbed out, lines touched up, unnecessary lines removed by painting them out with white or black ink according to the background, and, finally, a frame ruled around, if necessary.

The amount of reduction, which should be marked clearly on the margin, requires very careful consideration since under reduction may cause the reproduction to appear too coarse whilst over-reduction may result in the loss of the finer detail and the drawing may, moreover, appear spiritless.

It must also be remembered that a reduction of, say, ½ linear means that the reproduction will be a quarter the area of the original.

The best way to indicate the reduction required is to draw a vertical or horizontal line, parallel to a side or the base of the picture, of the exact length; or, the line may be roughly drawn and its length indicated by figures thus ——————2½"—————.

The question arises as to when line drawings for reproduction by the zinc block should be employed.

The answer is, Whenever possible.

The advantages to a reader of having the illustrations in the text has already been commented upon. It is about the only method commonly employed in which practically everything depends on the draughtsman; the author thus exercises the greatest control. Finally the fact that it is very inexpensive will appeal to editors and publishers.

As a matter of curiosity, the present writer picked out at random a recent volume of a scientific journal to examine the illustrations; although there were a number of text figures, an examination of the plates—chiefly lithographs and collotypes—showed that there were a large number of figures which ought to have been in the text. A more detailed inspection of the plates was therefore made, with the result that nearly 200 figures were found which with the minimum amount of alteration—merely drawing in ink instead of pencil in the majority of cases, and leaving out unnecessary shading in the others—could have been reproduced by line blocks. Ifthis had been done, a saving of over 20 per cent. could have been effected on the plates. Some of this would, of course, have been absorbed in the making of zincos, but not much, since line blocks of excellent quality can be obtained for 2½d. and 3d. per square inch. The above relates only to the most obvious examples; the saving in plates would have been enormous if the authors had drawn for the line process.

THE SWELLED GELATINE PROCESS.From the foregoing account of the line-block it may, perhaps, be thought that a drawing shewing the finest detail cannot be reproduced in the text by a relief block made by photo-chemical means. This is not the case; the swelled gelatine process is such that at its best the very finest work can be so reproduced. The method is not extensively used, chiefly owing to the remarkable amount of skill required to produce the best results and to the facts that the blocks take longer to make and are more expensive than the ordinary line block. This, however, should not militate against its use, for the increased cost is but very little, and the longer time in making, say two days, should not be of any consequence in a monthly or quarterly periodical. The great point in its favour is its great fidelity as compared with the ordinary photo-chemical relief blocks: for instance, a close cross-hatching reproduced by a line block will often come out as a series of white dots owing to the fact that at the points of intersection the black lines tend to thicken; hence, on printing, the white spaces, instead of being sharply cut and diamond-shaped, are rounded. This will not occur in a good block made by the swelled gelatine method. Further, the process does not restrict the draughtsman to dead black ink; the drawings may be made in pencil, crayon, or in ordinary writing ink: it is even claimed that wash drawings and photographscan be reproduced satisfactorily by this method. In the case of pencil drawings, the best results will be given when the surface of the paper used by the draughtsman is slightly rough; a pencil drawing on Bristol board, for example, will not be so well reproduced as one on ordinary smooth drawing paper. In brief, the process is as follows: a photographic negative of the drawing is made, and under it is exposed a bichromate gelatine plate. This plate is then developed in water. As already described, the gelatine will swell up in proportion to the amount of light to which it was exposed. The "positive" thus obtained will be in relief, the high lights being at a higher level than the shadows. A wax mould of the gelatine positive is then taken, covered with a thin layer of plumbago and electrically covered with copper. The "casting" so obtained is built up with metal and then mounted on wood in the same way as a zinco or a half-tone. The capabilities of the process may be judged by a study of Fig. 38, which is an extremely faithful reproduction of a lithograph, by S. Prout, by the swelled gelatine process.

Fig. 38Fig. 38. A Lithograph by S. Prout reproduced by the swelled gelatine process.

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THEquestion of cost is one of very great difficulty; in all probability no two firms will agree in their quotations for different kinds of work, and the reason for this lies in the large number of factors involved, many of which are very difficult to compute exactly. With respect to line engravings, etching, mezzotint, wood cuts and wood engravings, it is impossible to give any idea of the cost. It depends entirely on the complexity of the subject and the artist employed.

As regards lithographic processes for reproduction in one colour the cost varies with the nature of the work. If an artist be commissioned to make an autolithograph, the fee would be agreed upon beforehand. Photolithography and collotype, on the other hand, are processes which do not require the hand of an artist, and these methods of reproduction are relatively inexpensive. The price quoted by the lithographer or collotyper is for printing so many copies, hence the relative cost per copy depends upon the run and on the quality of the paper used. Lithography is cheaper than collotype; but if several illustrations are sent at the same time to be reproduced by collotype, the cost for each would be less than if sent separately.

In chromolithography a separate stone is necessary for each colour, hence the cost depends upon the number of stones used, and as several may be necessary to obtain a first-rate reproduction, it is obvious that the process may prove very expensive.

Turning to photomechanical processes, the prices vary according to the grade of work required—the best possible,good, and, lastly, cheap work. By best possible is meant the best that can be made under existing conditions, the price being immaterial; in good work the cost will be a limiting but not a preponderating factor, hence the work will be open to criticism; finally, in cheap work, the price is all important, so that the result is a block or a plate which will print well but which must not be criticized as regards its being a faithful reproduction of the original.

It is obvious that in the last two cases the quality of the work will depend upon the agreed price, whilst in the first case the cost will depend on the amount of time and skill required.

It is obvious, therefore, that a comparison of cost cannot be made between these grades; it is, however, possible to draw up a scale of relative cost of the processes under consideration for work of the same grade. In the table given below, A represents the best possible work, B indicates good work, and C stands for cheap work. Since the line block is the least expensive it is taken as the unit of price; that is to say, if a line block costs 3d. per square inch the cost of half tone, three colour half tone and photogravure would be 7¼d., 3s., and 1s. 2½d. respectively.

It must not be thought that if the area of a block is 3 square inches, the cost will, therefore, be 9d. There is, for obvious reasons, a minimum size at which the block or plate is charged although it may be smaller. These minima vary; in general terms they may be taken as 12 inches for line, half tone and swelled gelatine blocks, and 20 inches forhalf tone three colour blocks and photogravure plates. The measurements are the areas of the etched surface, the actual plate or block may be larger, but for this margin no charge is made.

With regard to cost of printing, nothing need be said about blocks which are set up with the type, namely line, swelled gelatine and coarse half tone blocks. The price of printing fine half tones and three colour blocks depends upon the quality of the paper used and the fineness of the work. Photogravure plates must be hand printed (photogravure printing on rotary machines is not considered here), and skill is required; for ordinary printing on good plate paper the price would be 10s. to 12s. 6d. per hundred copies, whilst for India printing the cost would be about 25s. for the same number.

Barnes:Illustrating Botanical Papers, Botanical Gazette, Vol. 43, 1907.Bock:Zincography, London, 1910.Cumming:Handbook of Lithography, London, 1904.Cundall:A Brief History of Wood-Engraving from its Invention, London, 1895.Gamble:Line Photo-engraving, London, n.d.Hamerton:Drawing and Engraving, London, 1892.Etching and Etchers, London, 1880.The Graphic Arts, London, 1882.Pennell:Lithography and Lithographers, London.Richmond:Grammar of Lithography, London, 1909.Robertson:The Art of Etching, London, 1885.Verfasser:The Half-tone Process, London, n.d.Wilkinson:Photo-mechanical Processes, London, n.d.

Barnes:Illustrating Botanical Papers, Botanical Gazette, Vol. 43, 1907.

Bock:Zincography, London, 1910.

Cumming:Handbook of Lithography, London, 1904.

Cundall:A Brief History of Wood-Engraving from its Invention, London, 1895.

Gamble:Line Photo-engraving, London, n.d.

Hamerton:Drawing and Engraving, London, 1892.Etching and Etchers, London, 1880.The Graphic Arts, London, 1882.

Hamerton:Drawing and Engraving, London, 1892.

Etching and Etchers, London, 1880.

The Graphic Arts, London, 1882.

Pennell:Lithography and Lithographers, London.

Richmond:Grammar of Lithography, London, 1909.

Robertson:The Art of Etching, London, 1885.

Verfasser:The Half-tone Process, London, n.d.

Wilkinson:Photo-mechanical Processes, London, n.d.

Some extraneous (duplicated) Headings on otherwise blank pages have been removed.

Each Footnote has been indented and placed beneath the paragraph to which it refers.

The Plates, which were on un-numbered pages, and some of the Figures, have been moved to (usually) below the paragraphs which first refer to them.

page 35: 'revelant' corrected to 'relevant' ... "See also the relevant works cited under Literature"

page 90: The Table of Costings does not appear to make sense, but has been left as in the original.

Hyphenation is not consistent in this book.

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