The PSE Standardized Philatelic Grading Scale enables a consensus expert opinions about single stamps and pairs to be expressed accurately and consistently using well-established philatelic terminology and an overall numeric grade. The following is a brief description of the overall guidelines.
Centering - First, PSE experts consider a stamps centering, and indicate their opinion as follows:
Gum Condition - Next, the stamps gum is examined, and the opinion indicated as follows:
GEM - Perfectly-balanced margins Post Office Fresh (POF)
Superb - Perfectly-balanced normal sized margins, POF
XF/S - Not quite perfectly-centered, POF
XF - Extremely well-centered margins, POF
VF/XF - Almost extremely well-centered, POF
VF - Very well-centered, POF
F/VF - Margins reasonably clear on all sides
F - Margins just clear on one or more sides
VG/F - Perfs touch or cut stamp design slightly
VG - Perfs cut into stamp design
OG - Original gum
NH - Never hinged
PH - Previously hinged
H - Hinged
DOG - Original gum, disturbed
POG - Part original gum
NG - Mint No gum
NGAI - Unused, no gum as issued (special printing)
USED - Used / canceled
Condition - Next, the stamps condition or soundness is considered. An example of potential faults is listed below. This list is not meant to be all inclusive, but rather an example of potential faults.
Faultless - Free of faults / Sound
VMF - Very Minor Fault (Minor gum fault on NH stamps, gum creases, gum wrinkles, tiny crease, corner crease, etc.)
MF - Minor fault (Tiny thin ~1 mm, toning, tiny tears ~.5 mm, tiny natural inclusions, short perf, etc)
F - Fault (Light crease, Natural straight edge (one side), small thin 1-4 mm, small tear ~1mm, etc.)
MAF - Major fault (Heavy or multiple creases, large or multiple tears, repairs e.g. filled thins or added perfs, large stains, etc.)
Altered - Reperforated, removed cancel, added cancel, etc. An altered stamp does not change the Scott Number
Fake - A genuine item that has been altered to appear as another Scott Number. e.g. Changing types, adding or removing perforations.
Counterfeit - Complete fabrication, not a genuine stamp.
Overall Numeric Grade - Finally, PSE's experts consider the appearance and soundness of the stamp and assign an overall numeric grade. The scale ranges from 10 to 100, 100 representing a stamp in flawless Gem condition. Twenty-five points are deducted straightaway for minor defects and 50 points for significant defects. Jumbo qualifiers (J) can be added after the numerical grade by PSE's experts in the event that the stamp falls into the proper category based on centering and condition, but has exceedingly large margins in comparison to the average of that stamp.
The basis for the PSE Standardized Philatelic Grading Scale is a follows.
GEM - 100
Superb - 98
XF/S - 95
XF - 90
VF/XF - 85
VF - 80
F/VF - 75
F - 70
VG/F - 60
VG - 50
G - 30
F/G - 20
F - 10
P - 5
Examples of PSE Standardized Grading Scale
A fully color illustrated, in depth look into how PSE authenticates and grades stamps can be found below.