I am using i3 as my window manager and I had uninstalled gnome, so the gnome solution didn't work for me. And the other software based approaches just made the screen look more black.
So, after a bit of reading, I came across brightctl.
Install it using apt install.
sudo apt install brightctl
You will need permissions to modify the display device, which only members of the group video(and obviously root) can do. So, make sure you add the current user to the video group. You can do this like so :
sudo usermod $(whoami) -a -G video
After installation, I can increase/decrease brightness using the below commands by 10 -- this is very gradual and gives me more control. :
#Increase brightness
/usr/bin/brightnessctl -d intel_backlight set +10
#Reduce brightness
/usr/bin/brightnessctl -d intel_backlight set 10-
I have added keybindings in my i3 config. Here is a snippet of the keybinding.
#Increase brightness
bindsym XF86MonBrightnessUp exec /usr/bin/brightnessctl -d intel_backlight set +10
#Reduce brightness
bindsym XF86MonBrightnessDown exec /usr/bin/brightnessctl -d intel_backlight set 10-