What is painting coefficient?

Painting co-efficents are the guideline value used to calculate the material and labour when applied in an unlevelled surfaces.

For example its difficult to calculate the painting area of a 3'0 x7'0 door all along its surfaces including frames and shutters.instead it can be understood that that the co -efficient value to calculate the area is approximately 1.3 times per side.that means 3'0x7'0 = 21 sft x 1.3 =27.3 sft per side is the chargeable area and 54.6 sft for both sides while the carpentry area is 21 sft per side .the co efficeints vary from surface to surfaces like wood or steel or like 2.0 times for carved areas .