Condition grading can sometimes be very confusing as it is a subjective evaluation and even veteran experts may disagree on some points. The overall quality must be taken into consideration before a grade can be determined. Many points must be examined in detail, both front and back, before a conclusion can be made. A close study of the centering, the perforations, the cancellation and the paper must be made in order to determine the presence of any hidden flaws. A very fine appearing stamp may under close examination be downgraded to fine or even to defect. This knowledge is necessary and very important as the grading of a stamp will dramatically influence the price of a stamp.