Hi,
Our board and committee governance model as well as our board culture is such that all board materials are visible to all directors. This assists in effectively delegating responsibility to committees while maintaining trust and openness.
Particular items may have visibility restricted to certain individuals, but even then it's usually members of management who are denied permission (management have board portal accounts at our organization too).
New directors are able to access all historical materials on the portal, subject to the same restrictions they inherit from their predecessors.
A notable exception is Nominating Committee material, for which certain materials may be redacted or kept confidential from the rest of board (either temporarily or permanently) at the discretion of the Corporate Secretary.
Another exception are matters concerning CEO remuneration, which are communicated directly from the relevant committee chair to the board and then from the board chair to the appropriate executive lead for processing. Records of dollar figures are generally not stored on the portal.
I like this model because it fosters a good culture and avoid the administrative hassle (not to mention risks) of managing permissions.
Hope this helps!