If you are considering making some serious manga for submission to a company, or if you want to create some manga as a hobby but want to make them the same size as professionals do, you might want to consider getting some manuscript paper, instead of just drawing on copy paper all the time.
There are several brands out there, but one trustworthy brand I have found is Deleter, which also makes other manga supplies, like pens, ink, white ink, screen tones, etc. They also have a wide selection of different types of comic book paper. They use this in Japan and South Korea for professional and doujinshi work, so that tells you something about their wide acceptability.
Their paper is divided by sizes, paper weight, and lining types.
The most commonly used sizes for manuscript paper is A4 and B4. Many manga artists use A4, which is close to the size that you will see reproduced in Shonen Jump, etc. Many artists also use the B4 size, which is significantly larger than the A4 and therefore allows for more detailed work. Also, having a drawing done on B4 and then shrunk down to A4 size produces a pretty pleasing effect on your art.
The paper weight just depends on your preference; whether you like heavier paper or lighter. Most people go with the heavier paper. The standard weights are 110kg and 135kg.
The problem I had was that there are no reviews out on the interwebs about the different ruler types. So that's the main reason I decided to write this review, for peoples' googling pleasure.
I just thought I'd give some information about the different types of papers and what the letters (A through F) mean. There was no review or detailed info out there so I bought some different kinds to see for myself. I can only talk about A, C, and F in detail because I only bought them.
note: unless otherwise noted (only in F, actually), all lines on these papers are in blue, non-reproducible ink that won't show up when you copy it.
A seems to be the standard type. A papers come with blue ruler scale marks along the edges, cut off lines, and bleed lines. This is the basic paper you want if you want to produce professional manuscripts ready for submission.
B has no lines.
C has simpler guidelines than A. It only has the outermost ruler grid and the inner main printing area marked. It lacks the cut off line and the bleed lines. Plus, the outer line (ruler scale) has narrower top and bottom margins than the A and F papers. Not sure what this is about.
D is geared for 4 frame manga so I wasn't interested in it.
E has gridlines printed in the printing area that are 3mm apart. Kind of unnecessary in my opinion, but who knows who will find it useful?
F is almost identical to A, with just one difference of having black tick marks along the rulers marking the center marks and cut off marks. Not a major difference, but may make a difference with the company you are submitting to (if you are).
In my opinion A and F are the standard papers to use if you want an easier time fitting your frames to the printable size. They have all the guidelines printed on the page (non-reproducible) so you are never uncertain how it'll turn out in print.
Where to get some? You can go to Japanimation.com or DeleterUSA.com or YesAnime.com