Dang! I did put the wrong video up. Mitch has two videos where he creates the colored clay balls. Apologies for the confusion.
There is another one where he shows the actual dusting technique and the posted one only shows how to make colored clay. Not bone dry.
But let's forget the videos.
The still photograph shows the tools and the result of what I've tried so poorly to convey.
The ball of clay, having been mixed wet with oxide, is bone dry. [chromium green in this case]
So, I take that bone dry ball of colored clay and lightly scrape it across a wire strainer [which I call dusting] and I'll get a pattern like that of the ware you've shared with us.
The higher up I hold the strainer the more faint the speckles will be. Any oxide or stain can be used. I have some with cobalt, RiO, like what's used in the ware you shared.
Of course in production, as your examples are, it's not manual as I describe but almost certainly, as @oldlady has pointed out, with a larger screen and likely a conveyor belt.
When I do this the colored dust settles on the pieces with no change to the surface texture - only color, such as those you've shared.
Am I saying this IS the way your shared ware was created? Nah. But you can easily achieve that look this way. As @Rae Reich mentioned, coming up with a glaze with such speckles is tricky. A simple semi-translucent white or even clear glaze is far easier, to which you can then add the speckles of your own choosing.
Again, apologies for my confusing attempts but as soon as I saw your images I immediately recognized one of the techniques I use.
I'm sorry I don't have finish fired images to share. Those pieces, like me, are in lock down elsewhere.