A non-luminous flame is colourless and is much hotter. A non-luminous flame undergoes complete combustion as it draws much more oxygen and gets much hotter. There are several "zones" within a non-luminous flame, and each zone has a different temperature.
The outermost zone of the flame is blue in colour and it is the hottest part. This is due to complete combustion.
The middle zone is moderately hot and is yellow in colour. This is because of partial combustion.
The innermost zone is the least hot and black in colour. This is due to the presence of unburned wax vapours.