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PANTOGRAPH or GUILLOCHE
The pieces are dipped in wax, and then the wax is scraped away in a particular pattern. After this is done, the glass is dipped in a mild acid. Where the wax has been scraped away, the acid burns a pattern in the glass.
SANDBLASTING
Parts of the piece that are not to be sandblasted are covered, and then a small nozzle is used to shoot a fine stream of silica at the piece. This technique is often used in combination with cutting.
COLOURING THE GLASS
To make coloured glass, different pigments are added to the glass-mass. For example, to produce green, copper oxide is added to the mixture. To produce blue, cobalt oxide is added. As well, it is possible to produce black, brown, red, orange, yellow and purple glass, in a myriad of shades.
CUTTING
Although it is possible to make some cuts in sodium potassium glass, lead crystal is the material of choice for this technique. Because of the higher refraction index of crystal, cuts in the crystal both add to the interest and appearance of the piece, as well as making it appear very clean and bright.
MACHINE ENGRAVING
Machine engraving is used on both hand-made and automatic production pieces. This technique is used to ensure uniformity from piece to piece.
Lead crystal, which is mouth blown in the traditional method, may from time to time have a few minor bubbles contained within the piece. This is generally accepted as a by-product of the traditional process and does not detract from the piece. On occasion, small, barely perceivable lines may be detected within a piece of crystal. These represent slight variations in the density of the molten crystal, which remain after the crystal has cooled. These lines are called cords and are also considered a by-product of the traditional process.
It should be noted that each piece of true hand cut lead crystal is a unique product of the individual artisan or artisans who have produced it. For example within a set of stemware of the same pattern there may be very slight variations in pattern size and spacing of the elements. This only serves to embellish the charm and appreciation of such artisanship and is by no means considered a detriment. Absolute product consistency is only achieved by fully mechanized production, not by a craftsperson.
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