Value

Here is a good example of 'value' in terms of colours. 

The white weft has diluted the warp colours.  The dark navy blue weft has enhanced them.

This is what the mantra:
White dilutes
Grey muddies
Black intensifies
means.

This photo also shows why nearly every answer to a weaving question begins with "It depends..."

By changing one element in the cloth being woven, the draw in has changed enormously.  The thicker weft takes up more room in the cloth, preventing the warp threads from scrunching up together.

The much finer navy weft doesn't take up nearly as much room in the cloth causing the warp threads to scrunch up more closely, increasing the draw in by about one inch on either side of the cloth.

Currently reading Cold in the Earth by Aline Templeton