Quote Originally Posted by The Wizard of BC View Post
Your phrase, "Pleating to the block", seems to be your personal phrase or perhaps the one used in your local circle.
I got the phrase from Iain Sherwood, proprietor of Cuillin Craft. He implies that that phrase was used in the Highland Outfitter/kiltmaking business he worked for in Scotland. You'd have to ask him about his source for that phrase. I don't know the name of the company in Scotland he was employed at.

It's a useful phrase for the method of pleating to an area of the tartan which has no vertical elements at all, that is, to a large vacant area of the sett. When I think of "pleating to the line" I think of each pleat having a prominent vertical line.

In many cases it's not clear, at distance, whether the pleat has no vertical element at all, or merely a very weak vertical element. So sometimes the difference is simply one of visual effect.

Here's an example:



At first glance there's no vertical element in the pleats, but maybe it's pleated to the pairs of rust lines in the purple band.