This morning I pressed the towels that were cut off the loom on Friday, and run through the washing machine last night.
The top photo shows the compression line fairly clearly - the bottom half of the cloth is smooth, while above it is not.
The middle photo shows the blue ridges of the weave structure standing proud from the rest of the cloth while the lower photo is after pressing. You can still see faint blue lines, but the cloth is now flat.
When we discussed wet finishing yesterday, I reviewed how the threads will move to areas of least resistance in the cloth. This aids in helping develop weave structures that require the movement of the yarns as in things like waffle weave, lace weaves, any weave structure that relies on the deflection of the yarns from their grid like warp and weft positions.
In this cloth, the centre of the motif is actually a small lace weave area. When held up to the light there are tiny 'holes' that allow the light to come through. The floats that create those holes make the cloth more absorbent - something desirable in a towel.
After compression the cloth will have increased stability. Cotton and linen will not, can not, full, so the compression of the warp and weft threads into each other will add stability.
In addition to all of that, the yarns we associate with shine, such as linen, will develop more shine. In the top most photo, you can just sort of see that the bottom that has been pressed is slightly shinier than the top half which has not.
And last but not least, wet finishing is a benefit because if the beat isn't completely even, or you have reed marks in the cloth, those will be reduced and in some cases eliminated altogether.
Lots of benefits involved in wet finishing.