BlackWatch may very well be the number two tartan in popularity - after Stewart Royal. It is a universal tartan and therefore for any man to wear. Women will wear it too, because it is very often used for kilted skirts or just skirts. You may also see it used in interior design.
The main colour is green/blue but on many of the pictures below it was necessary to lighten up colours in Photoshop, or the kilt had appeared black. Hence the name Black Watch.
In this gallery there are two different kilts in Black Watch tartan, starting out with a 5 yard off-the-peg kilt from Irish company, O'Neil of Dublin. The fabric is 10 oz. wool, meaning it is a lightweight kilt. The length is 23". Something special is that it is not lined. The sewing quality is excellent, but O'Neil seems to have stopped making kilts for men.
The other kilt is from Heritage of Scotland, a 5 yard John Morrison kilt made-to-measure. The length is 23" and the fabric is 16 oz. wool. In some of the oictures it is worn with accessories for dress-up events.
You'll notice that the tartans are not 100% identical. That is due to the fact that several varieties of the Black Watch tartan exist and that colors may vary from mill to mill and even from production to production. Also the fabric plays a role.