The usual fault with beginners is to draw the web too tight here and there. This is a fault to be specially avoided, for it causes the fabric to be drawn in, and to vary in width, spoiling its appearance and making the threads difficult to work upon; also the packing down of the weft could not be properly done, which would cause the warp-threads to be exposed in parts.
The thoroughness of this packing down of the weft is for several reasons very important. The durability of the work is much affected by it, both for the securing of the ends of wool already mentioned, and for the making of a strong, well-knit piece of fabric. Another reason is, that the drawing of the various forms in the design may be made incorrect, in this way: suppose an apple were woven in, apparently correctly, but the wefts were not pressed down thoroughly, the weaving and packing down of the wefts above it would be sure to press the part underneath closer together, and the effect of this would be to make the round apple assume a flattened oval shape, and cause similar changes throughout the work.
It has already been mentioned that wherever a change of colour occurs vertically, that is, in the direction of the warp-threads, there results of necessity a division or slit in the web; the slit, which may be of any length, if noticeable, must be closed. This can be done whilst the weaving is in progress by a method of interlocking the two wefts as they meet, or else by stitching up at the back when the work is finished. The latter way is called fine drawing, and must be very carefully done, especially with large tapestries.
Both methods are used; the first takes longer, but is the most durable. Old and worn tapestries will usually be seen to have given way where this stitching up at the back has taken place. In small pieces of work, however, there is not much likelihood of strain, so the oversewing at the back answers fairly well. The two ways can be used in conjunction. Supposing a border, owing to its being of a different colour, had to be joined the entire length of the work, the interlocking stitches might be made at intervals of about half an inch, and when the work was finished the oversewing at the back might be taken the entire length.
[Fig. 183] is a diagram illustrating the way in which the wefts may be interlocked whilst the weaving goes on. Examination of the drawing will probably be sufficient explanation; however, interlocking is effected thus: Commencing at the base, run a weft of the darker wool to and fro, leaving it slack at the turning point. A half pass of the lighter-coloured woof is then run through, it is threaded in an upward direction through the slack loop of the darker wool, waits there whilst another weft of the darker colour is worked, and then is threaded down through the second loop that has been formed, and returns to the starting-point. It then comes back again and is threaded upwards through this same loop, and waits, as before, for another to be formed, and returns back through it—and so on. If this is done properly, no change is visible on the right side. The joined weft will last as long as any other part of the weaving.
The process of stitching up at the back is simply an oversewing with silk or other strong thread. The stitches must be rather close, drawing the edges just sufficiently together, and they must not show through to the right side. The stitching together should be done while the work is on the loom, since the web would then be in less danger of pulling out of shape.