Finding the brightness and R,G,B combination being used in a desktop monitor

I have two desktop computers. The first one is: Lenovo. Description: Ubuntu 16.04.7 LTS, Release: 16.04, codename: xenial. The second one is: Dell Inspiron. Description: Ubuntu 18.04.5 LTS, Release: 18.04, codename: bionic. The first desktop has a comfortable brightness level. It does not require any special applications. For the second desktop, I have to use an application called “Brightness Controller”. In this application, I have to adjust four items: Brightness, R, G and B. I tried many combinations of the four items. But could not get the exact screen appearance as the first desktop. Is there a way to find out the “combination of the four items” that is being used in the first computer? Then I will be able to make the second computer also appear the same. Thanks.