Traditionally, in addition to the sizing, the paper would be laid on a smooth marble slab and polished with a smooth piece of marble or soapstone on both sides. The modern process is called "calendering" and is done with polished steel rollers.

Here is a link that might be useful: Calender at WikiPedia

thank you very much for your responcee. I will look into this. This may not make any sence, but do you think it would be possible to get a "supercalendered" finish, by making your own calender machine with polished steel rollers? I would imagine placing the wet sheet on a marble slab and rolling it a few times with a polished steel roller to brring the water quantity down? Just kinda thinking out loud here but what do you think? thanks again

As I understand it, polishing or calendering is done after the paper is dry. It's a combination of pressure and slippage that does the job, not just rolling.

I suspect using a steel roller on wet paper would just tear it up.

At about 8:56 in the linked video you'll see a couple of different finishing processes at a mill in England that was still making paper by hand at the time.

Here is a link that might be useful: Papermaking by hand at Hayle Mill, England in 1976

And another one: look starting at 6:48 in the linked video for the Korean method used for Hanji paper.

Here is a link that might be useful: Making hanji: Korean papermaking by Shin Hyun Seh

thank you for the responces. The "Making hanji" video looks very interesting.

Now I have another question in the same field...I have been wanting to get my family crest watermarked into what I will be making. I like being creative and am hoping to give this as a gift to a family member I havent seen in many years. I have a friend that owns and operates a machine shop and I have researched watermarks, and I have no doubt he can make a male and female mold of my familys crest. My understanding is that it would be them pressed into the screen that the pulp will be sitting on??? If this is the case, im worried while squeezing the water out through rollers and what not that it will distort the image? What would you recomend for this? I know its getting a bit advanced but this has been something I have wanted to try for a while so all the input is much appreciated.

In everything I've seen and read, a watermark on handmade paper is made of shaped wire that is sewn onto a mould. This makes the paper just a little thinner wherever the wire rises above the mesh on the mold. Pressing softens it just a little. You can see a watermark being applied in the Hayle Mill video.

In machine-made paper, the watermark is applied by a "dandy roll" during the pressing stage of the process, just before the paper goes through the drying rollers, I believe. The dandy is also what marks the paper with laid lines and other textures to simulate handmade paper.