

Oh sorry ! I didn’t see your new post ! So I have the response to the questions I just asked you here : https://jlai.lu/comment/14436651.
So, I’ll repeat myself for the other participants : since I started bookbinding, I keep everything that may be useful (cardboards from promotional calendar, marbled paper scraps, etc.).
The coptic binding method is quite easy (well it takes a little bit of patience on the first try), you can sew different signatures together and the notebook lays flat.
The Japanese method is much easier and quite decorative, but I don’t really like it for writing because the notebooks don’t open properly.

As usual, lots of tutorials on YouTube.
And here’s one of mine : 
PS : @[email protected] I see that you use brown ink, I love this shade.
Thank you ! To make the cover, I did not use a cardboard but A4 160 ou 180g/m2 drawing paper (Canson à Grain). I cut it in half and covered each part : one with japanese washi paper (the one with waves) and the other with canvas.
I prepared my signatures with sheets of smooth writing paper. Then, I sew them on one side of cover, on the “ribbon” parts (like on a “cousoir”). Then, all you need to do is to glue the other side. The only “tricky” part is measuring the thickness of the fabric you’ll be using for your cover, and deducting a few millimeters from the “ribbons” of your carboard.
But, you can also make it much more simple, like using a A4 180g/m2 paper, paint it (with watercolor or something else) on one side or the other of your paper, and cutting it in half without covering it.
@[email protected], if you like japanese paper, I recommend you Misaki Iinuma shop : https://www.misakiiinuma.com/ She’s japanese and travel to Japan each year to select papers. She’s fun and her tiny shop is near L’Écritoire and la Maison de la Poésie ;)