I used an app in Windows 7, I think called dimmer to make the screen change its contrast settings so I could dim it lower than the controls of the PC defaults such as function key or the power options in control panel.
Are there any of these type apps for Ubuntu 15.04 or approved for the latest Ubuntu LTS version on a PC-laptop.
My computer has the use of function keys that change its brightness. It uses a 0-8 step brightness scale where 0 is the least bright and 8 is the brightest. 0 is too bright for my comfort level especially at night
Following the suggestion in an answer below I added the following to etc/default/grub:
and updated grub
My screen brightness did not go any dimmer than it had before. Oddly the brightness level seems to go to level 2 brightness on a 0-8 scale every time I reboot which it did not do prior to the etc/default/grub change. I reverted my grub file back to previous settings.
I've installed Indicator-Brightness but this app does not dim my desktop any further than my function keys do and there are no menus to configure it to do so.
I actively pursued other related questions to find a solution and reporting results of that action here. Its a process that takes time. To those that have provided input, Thank you for being patient.
There are many aspects to graphics, screen brightness, contrasts, color temp, gamma.
xbacklight -set 50 xbacklight -dec 10 and 03 etc.
This never increased or decreased beyond the usual 0-8 steps the PC provides i.e. no difference than current function key levels.
Interestingly a comment below my question by Serg Kolo (thanks :) led me to info on
xrandr via the linked sources at the bottom of the information he provided concerning his script:
xrandr -q | grep " connected" xrandr --output LVDS1 --brightness 0.5
I had no idea this was available and already installed - apparently. With the second command in terminal my screen went darker than it ever has. I then tested:
xrandr --output LVDS1 --brightness 0.9
Which got me back to the usual lowest level. This appears to be changing contrast levels not brightness, which is exactly what I was asking about. A simple command in terminal is as good as an App.
I have since studied xrandr so that I can get an idea of how that command works.
Perhaps someone could explain xrandr in easy terms but until then please explore the information from the link above.
Edit Sept 16
In good faith and collaboration I decided to try the script from Serg's answer below. Following his directions I was able to make this script work for me. I wish I knew how the script determines what the name of my screen is for the use of
xrandr command but the good news is it works.
Thank you Serg and all for your input