Handling of the product has a great deal of effect on the pattern match. Different products have more or less effect. Generally, the stiffer and thicker the product, the more pronounced the effect will be. The tighter or smaller the roll, the more the material must bend (stress) to conform. In order to bend, something must stretch, and the greater the bend, the more the stretch. That is why the pattern repeat length is longer on the inside of a roll than on the outside.
It is important that the piece of material with the shortest repeat length is installed first. Since each succeeding piece of material should be stretched slightly more than the preceding piece, the pattern can be readily matched during the installation by preshrinking.
If the first piece installed is the longest repeat length, it is almost impossible to stretch the second piece and make it match.