How can I print the log for a branch other than the current one?

TL;DR

Use

git log <branch>

where <branch> is the name of the branch of interest.

From the git-log man-page…

A simplified version of the git-log synopsis given in that command’s man page is

git log [<revision range>]

Further down, you can find the following passage:

When no <revision range> is specified, it defaults to HEAD (i.e. the whole history leading to the current commit)

In others words, git log is equivalent to git log HEAD. If you’re on a branch, called mybranch, say, this command is also equivalent to git log mybranch.

You want to limit the log to commits reachable from another branch, i.e. a branch you’re not currently on. The easiest way to do that is to explicitly pass the name of the branch of interest to git log:

git log <branchname>

See the gitrevisions manpage for more details about the many forms that the <revision-range> argument can take.