Mentor is a dark, low-contrast colorscheme for Vim based on the awesome Apprentice by Romain Lafourcade, which is based on Sorcerer by Jeet Sukumaran.

It is essentially a daker, more minimal version of Apprentice (Chill Mentor uses the lighter, lower-contrast background of Apprentice), with most of the yellow replaced with ocre. Colors are entirely taken from the default xterm palette to ensure a similar look in 256colors-ready terminal emulators and GUI Vim. Mentor also has neovim/treesitter-compatible versions that I am slowly updating as I come across scenarios that look weird in neovim.

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Here is some of the relevant documentation from Apprentice

Mentor is a direct fork of Apprentice. I will eventually get around to updating the docuementation. For now this is what it is.

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Preparing your environment

Apprentice is designed first and foremost to look “good” in terminal emulators supporting 256 colors and in GUI Vim (GVim/MacVim). It supports lesser terminal emulators in the sense that it doesn’t break but it will definitely look “better” in more capable environments.

GVim/MacVim

There is nothing to do for GVim/MacVim as GUI Vim supports “True Color” by default.

“True Color” terminal emulators

Since January 2016, Vim has been able to talk in “True Color” to terminal emulators supporting that feature. This means that it is now not only possible but also very easy to have the exact same colors in TUI Vim and GUI Vim.

In practice, this new development doesn't change much for Apprentice which uses the exact same colors in the GUI as it does in the TUI anyway. But you can still try “True Color” if your setup satisfies the requirements with the following command:

:set termguicolors

See this gist for more information and support status and, of course, :help 'termguicolors'.

256color-ready terminal emulators

Most terminal emulators in use nowadays can display 256 colors but most of them use a default TERM that tells Vim otherwise. Assuming your terminal emulator actually supports 256 colors, you must instruct it to brag about its terminal-hood by setting the correct TERM environment variable.

The “ideal” TERM usually includes the string 256color, like xterm-256color. The actual value is highly dependent on your terminal emulator and/or your terminal multiplexer, though, so you will have to refer to their manual.

Working with 8/16 colors

As an alternative to changing your default TERM to xterm-256color or similar, you can keep its default value (usually something like xterm or screen) and set your terminal emulator to use the Apprentice colorscheme instead of its default colors.

The table below contains a subset of Apprentice’s palette. You can use a color picker or copy/paste these values:

Intensity	Normal	Intensity	Bright
0	#1C1C1C ![#1C1C1C][0]	8	#444444 ![#444444][0]
1	#AF5F5F ![#AF5F5F][1]	9	#FF8700 ![#FF8700][9]
2	#5F875F ![#5F875F][2]	10	#87AF87 ![#87AF87][10]
3	#87875F ![#87875F][3]	11	#FFFFAF ![#FFFFAF][11]
4	#5F87AF ![#5F87AF][4]	12	#87AFD7 ![#87AFD7][12]
5	#5F5F87 ![#5F5F87][5]	13	#8787AF ![#8787AF][13]
6	#5F8787 ![#5F8787][6]	14	#5FAFAF ![#5FAFAF][14]
7	#6C6C6C ![#6C6C6C][7]	15	#FFFFFF ![#FFFFFF][15]
Foreground color	#BCBCBC ![#BCBCBC][16]	Background color	#262626 ![#262626][17]

Here is a sample ~/.Xresources for you Linux/BSD users. You can import this into terminal.sexy to convert it to the appropriate color scheme format for your preferred terminal emulator:

*.foreground: #BCBCBC
*.background: #262626
*.color0:     #1C1C1C
*.color8:     #444444
*.color1:     #AF5F5F
*.color9:     #FF8700
*.color2:     #5F875F
*.color10:    #87AF87
*.color3:     #87875F
*.color11:    #FFFFAF
*.color4:     #5F87AF
*.color12:    #87AFD7
*.color5:     #5F5F87
*.color13:    #8787AF
*.color6:     #5F8787
*.color14:    #5FAFAF
*.color7:     #6C6C6C
*.color15:    #FFFFFF

And a sample ~/.minttyrc for you Cygwin users:

ForegroundColour=188,188,188
BackgroundColour=38,38,38
Black=28,28,28
Red=175,95,95
Green=95,135,95
Yellow=135,135,95
Blue=95,135,175
Magenta=95,95,135
Cyan=95,135,135
White=108,108,108
BoldBlack=68,68,68
BoldRed=255,135,0
BoldGreen=135,175,135
BoldYellow=255,255,175
BoldBlue=135,175,215
BoldMagenta=135,135,175
BoldCyan=95,175,175
BoldWhite=255,255,255

All terminal emulators

I recommend adjusting your terminal's background color to the one used in Apprentice if you want to avoid having a “frame” around Vim:

Notation	Value
xterm	235
hexadecimal	#262626
rgb	rgb(38,38,38)

Installing Apprentice

Colorschemes must be placed in a directory named colors that is somewhere in Vim’s runtimepath:

The canonical location is:

colors/apprentice.vim

but it could be:

" with Pathogen
bundle/apprentice/colors/apprentice.vim

or:

" with :help packages
pack/foobar/start/apprentice/colors/apprentice.vim

or whatever works for you.

Arch users may be happy to hear that Apprentice has landed in AUR. To install it, use an AUR helper:

$ yaourt -S vim-apprentice

or download the PKGBUILD and do:

$ makepkg -i

NOTE: that package is maintained by a third-party so YMMV.

Enabling Apprentice

To test Apprentice, just type this command from normal mode and hit Enter:

:colorscheme apprentice

If you like what you see and want to make Apprentice your default colorscheme, add this line to your vimrc, preferably near the end, after any syntax enable, syntax on, filetype ... on, call plug#end(), or call vundle#end() line:

colorscheme apprentice

Tweaking Apprentice

If you don't want to maintain your own fork of Apprentice you can add something like this to your vimrc, before colorscheme apprentice:

function! MyApprenticeOverrides() abort
    highlight Comment ctermfg=245
    highlight NonText ctermbg=17
endfunction

augroup MyColors
    autocmd!
    autocmd ColorScheme apprentice call MyApprenticeOverrides()
augroup END

See this Gist for reference.

Hacking Apprentice

Originally written manually, Apprentice switched to a template based on romainl/vim-rnb a few years ago, which made the life of the author and contributors much easier even if the rate of change had been pretty low for quite a while.

Following the author's involvement with the vim/colorschemes project, Apprentice is now using a noticeably more powerful templating system: lifepillar/colortemplate that is on its way to become the official standard.

You can find the template under colortemplate/. See :help colortemplate for further instructions.

If you feel like making a pull request, make sure you commit both the modified template and the modified colorscheme.