ROUND ETCHING.Its object is to remove the last formed grade. Coat the plate with a very uniform coating of ink, corresponding to the one used in middle etching. A{91}criterion for correct coating is, that only the grade caused by middle etching be covered, while the grade from deep etching must remain exposed. Remember also that in heating the plate a further spreading is caused by melting.
Its object is to remove the last formed grade. Coat the plate with a very uniform coating of ink, corresponding to the one used in middle etching. A{91}criterion for correct coating is, that only the grade caused by middle etching be covered, while the grade from deep etching must remain exposed. Remember also that in heating the plate a further spreading is caused by melting.
To the inexperienced it may happen that the grade caused by deep etching is of variable width. These places must be removed by working over with a graver before continuing, as otherwise we will not attain symmetrical round etching.
The plate prepared for the latter treatment is only dusted once in resin, and then blown out. It is then heated to 45° C., and is dusted and heated twice with asphaltum at increasing temperature, just as in both the previous processes. Nothing now remains to be scratched away. After having varnished the back, the plate is etched in the middle etching bath two or three times for three minutes. At the end of each period examine whether another whole period is necessary, or whether rounding the plate requires less time. When this is over (several parts, which perhaps were already finished beforehand, have been covered), wash and approach the next problem, the removal of the grade resulting from the middle etching. This is called
CLEAN ETCHING.Upon the clean, smooth rollers spread thick transfer ink and roll it out perfectly. It is advisable to warm the stone previously with a little alcohol, which promotes the working out of the color. When the surface of the color has become perfectly uniform the plate is rolled in slowly and without pressure. Pressure would deposit too much color in the finest recesses, and prevent the clean etching and sharpening of the same, thus causing lack of harmony in the prints.
Upon the clean, smooth rollers spread thick transfer ink and roll it out perfectly. It is advisable to warm the stone previously with a little alcohol, which promotes the working out of the color. When the surface of the color has become perfectly uniform the plate is rolled in slowly and without pressure. Pressure would deposit too much color in the finest recesses, and prevent the clean etching and sharpening of the same, thus causing lack of harmony in the prints.
It is better to coat the shadows with a pad, as they require more color.
The plate, thus blackened, is to be dusted once with the finest asphalt powder, then freed from excess by dusting off and blowing until the coating becomes brilliant.
Clean etching then takes place in the bath for etching on, in periods of one minute each, and repeatedly until the last thread has disappeared.
Now everything is ready for a proof, and for subsequent mounting.
Fig. 8.
Fig. 8.
Fig. 6 shows a print of the little picture given during the process of middle and deep etching, and admits of an instructive comparison during the progress of the work.{92}
Proofs are made from the cleaned plate (the back of which has been scratched clean) in the following manner: Upon a good lithographic roller place a quantity of the best ink and coat the etching uniformly. Help the shadows along by dabbing on some ink with a leather pad. When this is done, carefully rub off the excess in the lightest spots, and fix the plate in the rolling-press; place on it a sheet of well-calendered tissue paper, next a sheet of writing paper, a sheet of Bristol paper, and a cardboard. With very little pressure (the thickness of one cardboard less than in the transfer) draw it through. If the print is too weak, place paper below, sheet by sheet. The stronger spots may be blackened separately.
FINISHING AND MOUNTING THE PLATE.The first thing to be done is the removal of the black edge left by etching and the sawing out of such spots in the drawing as were spared for this from the beginning. The waste may be removed by means of a circular saw or a fine-toothed carpenter’s saw. Do not, however, forget to leave behind a margin of about three millimetres for the purpose of nailing the plate to the wood. The edges must be smoothed with a graver, filed and chipped off to a suitable plane, since sawing produces a sharp edge.
The first thing to be done is the removal of the black edge left by etching and the sawing out of such spots in the drawing as were spared for this from the beginning. The waste may be removed by means of a circular saw or a fine-toothed carpenter’s saw. Do not, however, forget to leave behind a margin of about three millimetres for the purpose of nailing the plate to the wood. The edges must be smoothed with a graver, filed and chipped off to a suitable plane, since sawing produces a sharp edge.
To remove the spots spared in the drawing, bore a hole through the metal at that spot with an American gimlet, introduce a scroll saw, and thus cut out the metal. The edge should be worked over with a dog-leg chisel.
By aid of the borer we also make the conical holes in the edge, through which the nails are to be hammered. Elevations caused on the back of the plate by boring should be removed by filing.
The block of wood which is to raise the height of the plate to that of type should be cut from perfectly dry maple, oak, or mahogany wood. With the plate it must just reach to the top of the type; the sides must be parallel, and all should be perfectly smooth.
Cutting at right angles can be done with a circular saw or with the aid of a mitre saw used by printers for such work. For exact examination of height,{93}pass the block and zinc through the caliber-bridge (Fig. 9). Roughen the base and top surface of the block with a toothing-plane. When convinced that the block fits perfectly, nail the etching upon it, taking care to drive the heads of the nails well into the holes provided for them, otherwise they will show in the print. If other small details are noticed, they may be removed with a dog-leg chisel.
Fig. 9.
Fig. 9.
This finishes the plate for delivery.
In the expounded explanation of my chemigraphical method, the following arrangement may serve the beginner as a guide to the manipulations from the beginning to the end of the work:
1. Planing the plate. 2. Grinding it out. 3. Freeing from fat, and then testing its cleanliness. 4. Transferring the drawing to the metal. 5. Preparing the metallic surface after transfer. 6. Strengthening the transferred drawing by rubbing, rolling, or flooding it as directed. 7. Transmutation of the transferred drawing into a resisting etching varnish by double besprinkling and burning in of asphaltum, subsequent to covering the edges and large light parts, and after varnishing the back. 8. Sharp or preliminary etching, strengthening with resin powder, and finishing preliminary etching. 9. Washing and examining the work. 10. Coating with etching ink for middle etching. 11. Formation of the etching varnish by double dusting and increasing burning-in of (a) resin and (b) asphalt; varnishing the back. 12. Chiselling out the lights of the picture. 13. Middle etching. 14. Washing and examining the result. 15. Coating for deep etching. 16. Formation of etching varnish by dusting, heating with increasing strength of resin and asphaltum; varnishing the back. 17. Deep etching. 18. Washing out and examining. 19. Coating for round etching. 20. Formation of etching varnish by single dusting and warming of resin, and double dusting and burning-in of asphaltum; varnishing the back. 21. Round etching. 22. Washing and examining the plate. 23. Coating for clean etching. 24. Formation of etching varnish by single dusting and burning-in of asphaltum at a high temperature. 25. Clean etching. 26. Washing and scraping the back. 27. Proofs. 28. Cutting out and mounting the plate.