Stupid Question. Grain direction.

[BigSi]

It's been quite awhile since I have done any perfect bound books. A or B for grain direction. (see attached) I don't want the covers to curl when completed.
Sorry! I know a real basic question, (I shouldn't have to ask). thanks Simon

 

[gordo]

B

 

[Stickman42]

Is B used specifically to prevent cover curl? I perfect bind thousands per day and standard procedure is to have cover grain parallel to the spine. It makes for a cleaner spine fold. Understandably creasing/scoring would help if cover grain ran the other way. I've just never heard of a solid reason to have the cover grain going perpendicular to the spine. My experience with curl has been mostly due to lamination and/or environment.

 

[SteveSuffRIT]

It should be A, grain parallel to spine/backbone.
B will look like wave edge paper.

 

[Stickman42]

It should be A, grain parallel to spine/backbone.
B will look like wave edge paper.

@BigSi - just to make this clear, both the interior paper and the cover paper should have the grain running parallel with the spine.

 

[gordo]

This is why I said B.
I think it depends on the weight of the paper - I don't have an example of 350 gsm as a guide so A may work if the paper is thick enough.
Ideally and typically the grain would be parallel to the spine (A).
But depending on the weight of the paper it may be better to have the paper cross the grain.
If the grain is parallel to the spine then the paper can curl as below.

But if the grain goes across the spine (B) then the spine prevents it from curling top and bottom and the stiffness of the paper grain prevents it from curling up from the right.
Unfortunately that usually means scoring the paper to prevent cracking at the fold.

 

[BigSi]

Thanks everyone for your input.

My thinking is "A" for the internal pages and "B" for the cover. (assuming of course I crease the cover) This way I eliminate the chance I'll get curl on the cover.

ta Simon