Does higher thread count mean that fabric is more down proof?

Again, not necessarily. A thread count of at least 220 is necessary to make a downproof fabric that is not excessively stiff and heavy. Using smaller yarns leaves more space in the weave, and raising the thread count does not always compensate fully. Even spacing is also important; otherwise down can leak through the less densely packed area. Weaves that have the same warp count as weft count are more stable than fabrics that have a much higher count in one direction than the other. Cambric weaves alternately pass the weft yarns one over the warp and one under. Cambric is inherently more stable than twill and sateen weaves which pass two over one or three over one. We have noted that many of the damask look twills from the orient are quite leaky in spite of a high thread count. That is not to say that twill and sateen weaves cannot be downproof. The weaving pattern allows a higher thread count, and if the yarns are tightly packed, twills and sateen weaves make some of the finest ...  more