Читать книгу Stained Glass Work: A text-book for students and workers in glass - Christopher Whall - Страница 8

Cutting (advanced)—The Ideal Cartoon—The Cut-line—Setting the Cartoon—Transferring the Cut-line to the Glass—Another Way—Some Principles of Taste—Countercharging.

We have only as yet spoken of the processes of cutting and painting in themselves, and as they can be practised on a single bit of glass; but now we must consider them as applied to a subject in glass where many pieces must be used. This is a different matter indeed, and brings in all the questions of taste and judgment which make the difference between a good window and an inferior one. Now, first, you must know that every differently coloured piece must be cut out by itself, and therefore must have a strip of lead round it to join it to the others.

Draw a cartoon of a figure, bearing this well in mind: you must draw it in such a simple and severe way that you do not set impossible or needlessly difficult tasks to the cutter. Look now, for example, at the picture in Plate V. by Mr. Selwyn Image—how simple the cutting!

You think it, perhaps, too "severe"? You do not like to see the leads so plainly. You would like better something more after the "Munich" school, where the lead line is disguised or circumvented. If so, my lesson has gone wrong; but we must try and get it right.

You would like it better because it is "more of a picture"; exactly, but you ought to like the other better because it is "more of a window." Yes, even if all else were equal, you ought to like it better, because the lead lines cut it up. Keep your pictures for the walls and your windows for the holes in them.

But all else is not equal: and, supposing you now standing before a window of the kind I speak of, I will tell you what has been sacrificed to get this "picture-window" "like a picture." Stained-glass has been sacrificed; for this is not stained-glass, it is painted glass—that is to say, it is coloured glass ground up into powders and painted on to white sheets of glass: a poor, miserable substitute for the glorious colour of the deep amethyst and ruby-coloured glasses which it pretends to ape. You will not be in much danger of using it when you have handled your stained-glass samples for a while and learned to love them. You will love them so much that you will even get to like the severe lead line which announces them for what they are.

But you must get to reasonably love it as a craft limitation, a necessity, a thing which places bounds and limits to what you can do in this art, and prevents tempting and specious tricks.

How to Make a "Cut-line."—But now, all this being granted, how are we to set about getting the pieces cut? First of all, I would say that it is always well to draw most, if not all, of the necessary lead lines on the cartoon itself. By the necessary lead lines I mean those which separate different colours; for you know that there must be a lead line between these. Then, when these are drawn, it is a question of convenience whether to draw in also the more or less optional lead lines which break up each space of uniform colour into convenient-sized pieces. If you do not want your cartoon afterwards for any other purpose you may as well do so: that is, first "set" the cartoon if it is in charcoal or chalk, and then try the places for these lead lines lightly in charcoal over the drawing: working thus, you can dust them away time after time till they seem right to you, and then either set them also or not as you choose.

A good, useful setting-mixture for large quantities is composed by mixing equal parts of "white polish" and methylated spirit; allowing it to settle for a week, and pouring off all that is clear. It is used in the ordinary way with a spray diffuser, and will keep for any length of time.

The next step is to make what is called the cut-line. To do this, pin a piece of tracing-cloth over the whole cartoon; this can be got from any artist's-colourman or large stationer. Pin it over the cartoon with the dull surface outwards, and with a soft piece of charcoal draw lines 1/16 to 1/8 of an inch wide down the centre of all the lead lines: remove the cloth from the cartoon, and if any of the lines look awkward or ugly, now that you see them by themselves undisguised by the drawing below, alter them, and then, finally, with a long, thin brush paint them in, over the charcoal, with water-colour lamp-black, this time a true sixteenth of an inch wide. Don't dust the charcoal off first, it makes the paint cling much better to the shiny cloth.

When this is done, there is a choice of three ways for cutting the glass. One is to make shaped pieces of cartridge-paper as patterns to cut each bit of glass by; another is to place the bits of glass, one by one, over the cut-line and cut freehand by the line you see through the glass. This latter process needs no description, but you cannot employ it for dark glasses because you cannot see the line through: for this you must employ one of the other methods.

How to Transfer the Cutting-line on to the Glass.—Take a bit of glass large enough to cut the piece you want; place it, face upwards, on the table; place the cut-line over it in its proper place, and then slip between them, without moving either, a piece of black "transfer paper": then, with a style or hard pencil, trace the cutting-line down on to the glass. This will not make a black mark visible on the glass, it will only make a grease mark, and that hardly visible, not enough to cut by; but take a soft dabber—a lump of cotton-wool tied up in a bit of old handkerchief—and with this, dipped in dry whitening or powdered white chalk, dab the glass all over; then blow the surface and you will see a clear white line where the whitening has stuck to the greasy line made by the transfer paper; and by this you can cut very comfortably.

But a third way is to cut the shape of each piece of glass out in cartridge-paper; and to do this you put the cut-line down over a sheet of "continuous-cartridge" or "cartoon" paper, as it is called, and press along all the lines with a style or hard pencil, so as to make a furrow on the paper beneath; then, after removing the cut-line, you place a sheet of ordinary window-glass below the paper and cut out each piece, between the "furrows" leaving a full 1/16 of an inch. This sixteenth of an inch represents the "heart" or core of the future lead; it is the distance which the actual bits of glass lie one from the other in the window. You must use a very sharp penknife, and you will find that, cutting against glass, each shape will have quite a smooth edge; and round this you can cut with your diamond.

This method, which is far the most accurate and craftsmanly way of cutting glass, is best used with the actual diamond: in that case you feel the edge of the paper all the time with the diamond-spark; but in cutting with the wheel you must not rest against the edge of the paper; otherwise you will be sure to cut into it. Now, whichever of all these processes you employ, remember that there must be a full 1/16 of an inch left between each piece of glass and all its neighbours.

The reason why you leave this space between the pieces is that the core of the lead is about that or a little less in thickness: the closer the glass fits to this the better, but no part of the glass must go nearer to its neighbour than this, otherwise the work will be pressed outwards, and you will not be able to get the whole of the panel within its proper limits.

Fig. 34.

Fig. 34 is an illustration of various kinds and sizes of lead; showing some with the glass inserted in its place. By all means make your leads yourself, for many of those ready made are not lead at all, or not pure lead. Get the parings of sheet lead from a source you can trust, and cast them roughly in moulds as at fig. 35. Fig. 36 is the shears by which the strips may be cut; fig. 37 is the lead-mill or "vice" by which they are milled and run into their final shape; fig. 38 the "cheeks" or blocks through which the lead passes. The working of such an instrument is a thing that is understood in a few minutes with the instrument itself at hand, but it is cumbrous to explain in writing, and not worth while; since if you purchase such a thing, obviously the seller will be there to explain its use. Briefly,—the handle turns two wheels with milled edges 1/16 of an inch apart; which, at one motion, draw the lead between them, mill it, and force it between the two "cheeks" (fig. 38), which mould the outside of the lead in its passage. These combined movements, by a continuous pressure, squeeze out the strip of lead into about twice its length; correspondingly decreasing its thickness and finishing it as it goes.

Fig. 35.

Fig. 36.

Fig. 37.

Some principles of good taste and common sense with regard to the cutting up of a Window; according to which the Cartoon and Design must be modified.—Never disguise the lead line. Cut the necessary parts first, as I said before; cut the optional parts simply; thinking most of craft-convenience, and not much of realism.

Fig. 38.

Do not, however, go to the extent of making two lead lines cross each other. Fig. 39 shows the two kinds of joint, A being the wrong one (as I hold), and B the right one; but, after all, this is partly a question of taste.

Do not cut borders and other minor details into measured spaces; cut them hap-hazard.

Fig. 39.

Do not cut leafage too much by the outlines of the groups of leaves—or wings by the outlines of the groups of feathers.

Do not outline with lead lines any forms of minor importance.

Do not allow the whole of any figure to cut out dark against light, or light against dark; but if the figure is ever so bright, let an inch or two of its outline tell out as a dark against a spot of still brighter light; and if it is ever so dark, be it red or blue as strong as may be, let an inch or two of its outline tell out against a still stronger dark in the background, if you have to paint it pitch-black to do so.

By this "countercharging" (as heralds say), your composition will melt together with a pleasing mystery; for you must always remember that a window is, after all, only a window, it is not the church, and nothing in it should stare out at you so that you cannot get away from it; windows should "dream," and should be so treated as to look like what they are, the apertures to admit the light; subjects painted on a thin and brittle film, hung in mid-air between the light and the dark.