On my system I have *ImageMagick* and its documentation installed:

 $ apt-cache pkgnames imagemagick
 imagemagick
 imagemagick-6.q16
 imagemagick-dbg
 imagemagick-doc
 imagemagick-common

I can access `convert`'s *man* page, which tells me SEE ALSO `ImageMagick(1)` if I want to know more.

`man ImageMagick` says `No manual entry for ImageMagick`.

And finally, `man -k imagemagick` says:

 quantize (5) - ImageMagick's color reduction algorithm.

How do I access [*ImageMagic*'s *man* page](https://linux.die.net/man/1/imagemagick) on my system?

# Additional information

Above I was mistaken.
`apt-cache pkgnames` listed packages are "not necessarily available to download, installable or installed" (ref. `APT-CACHE(8)`).
So, my command did not list the installed packages.

Digging more, I ended up with

 $ apt list imagemagick* 
 Listing... Done
 imagemagick/xenial-updates,xenial-security,now 8:6.8.9.9-7ubuntu5.4 amd64 [installed]
 imagemagick-6.q16/xenial-updates,xenial-security,now 8:6.8.9.9-7ubuntu5.4 amd64 [installed,automatic]
 imagemagick-common/xenial-updates,xenial-updates,xenial-security,xenial-security,now 8:6.8.9.9-7ubuntu5.4 all [installed,automatic]
 imagemagick-dbg/xenial-updates,xenial-security 8:6.8.9.9-7ubuntu5.4 amd64
 imagemagick-doc/xenial-updates,xenial-updates,xenial-security,xenial-security 8:6.8.9.9-7ubuntu5.4 all

So, apparently, `imagemagick-doc` was not installed.
Nevertheless, this package installs the `www` documentation (`/usr/share/doc/imagemagick-doc/www`) and not the *man* one.

Checking the content of the `imagemagick` package does not give away what the name of its *man* page is, or at least, I am not able to figure it out.

 $ dpkg -L imagemagick | grep man
 /usr/share/man
 /usr/share/man/man1
 /usr/share/man/man1/stream-im6.1.gz
 /usr/share/man/man1/display-im6.1.gz
 /usr/share/man/man1/animate-im6.1.gz
 /usr/share/man/man1/mogrify-im6.1.gz
 /usr/share/man/man1/composite-im6.1.gz
 /usr/share/man/man1/montage-im6.1.gz
 /usr/share/man/man1/import-im6.1.gz
 /usr/share/man/man1/identify-im6.1.gz
 /usr/share/man/man1/conjure-im6.1.gz
 /usr/share/man/man1/convert-im6.1.gz
 /usr/share/man/man1/compare-im6.1.gz

# Bug reports here

 - ImageMagick: I've opened a bug report [here](https://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=31522).

 - Debian: another bug report [here](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=856997).

Let's see if someting comes up.