The oxidising flame is the flame produced with an excessive amount of oxygen. When the amount of oxygen increases, the flame shortens, its colour darkens. All of the carbon that gets used can be turned into CO, so there's actually no soot. This means that there is complete oxidation and due to increasing darkening, it doesn't produce much light and becomes non-luminous. Due to this reason, non-luminous flame is also called oxidising flame.
In luminous flame, there is partial oxidation due to lesser availability of oxygen. A luminous flame is a bright, light emitting, usually yellow due to unburnt carbon or hydrocarbons which reduce the oxygen contained in the materials processed with the flame. Due to this reason, luminous flame is also called as reducing flame.
