We have explained the relative humidity and absolute humidity to 2-5 from 2-1.
Let’s check again here.
Quantity the water of which exists in the air with absolute humidity
Even if it heats air, since the weight of the water vapor is constant, absolute humidity does not change.
Quantity the water of which has actually melted with relative humidity to the amount of quantity = saturation water vapor of the water which can melt into the air.
Numerator: Vapor which actually exists (actual)
Denominator: Quantity of the water which able to melt into the air = the amount of saturation water vapor (possibility)
If air is heated, the thermal expansion of air and the numerator which constitutes air will be activated, and the amount of saturation water vapor will increase.
That is, the numerator is constant, but the denominator is increased, and the relative humidity decreases.
In the production process of the factory, since it returns to normal temperature at the shipping even if it carries out high-temperature processing, the process design and management by absolute humidity are required.
Related page:
2-5.Absolute humidity 
2-4.Relative humidity RH 
2-1.What is the humidity? 
2-3.Ask for saturation water vapor pressure 
2-10.The Psychrometric charts 
2-2.There is a limit to the water vapor contained in the air 
4-3.Drying speed and temperature of the hot air 
1-5.Equilibrium moisture content and Critical moisture content – Influence of temperature and relative humidity