The four sub-grades.

When PSA, BGS, CGC, SGC, or TAG looks at your card, they don't form a single holistic opinion. They break the card into four dimensions, score each one independently, then combine those scores into the overall grade on the label. This is the sub-grade system, and it's the bedrock of every grading service's methodology.

The four pillars are universal: centering, corners, edges, and surface. The differences between services come down to two things: how strictly they enforce each pillar's threshold, and how they weight the four together when calculating an overall grade. The pillars themselves don't change. A grader at PSA, BGS, CGC, SGC, and TAG are all looking at the same physical features of the card; they just have slightly different tolerances for what counts as “clean” on each one.

This guide walks through each pillar — what graders are physically measuring, what separates a 10 from a 9 to an 8, and the failure modes that tank otherwise clean cards. Understanding this is the single biggest skill jump you can make if you're submitting cards regularly; it's the difference between a 9 you saw coming and a 9 that ruined your day.

How the four combine.

Before we dig into each individual pillar, the most important rule in all of grading:the worst sub-grade caps the overall grade. If your card has perfect centering, perfect corners, perfect edges, and a single visible scratch on the surface, the overall grade is capped at whatever the surface sub-grade gets. Not the average. The minimum.

This is why “improving the average” on a card doesn't help. If you have a card with one weak pillar, that pillar is your ceiling regardless of how good the others are. Plan around the worst, not the average.

How each service weights the four when calculating the overall:

• PSA uses overall grade only on the label, but the internal scoring follows the same four-pillar logic. Their published guidance suggests centering and surface are weighted slightly more heavily than corners and edges in close-call situations.
• BGS prints all four sub-grades on the label. The overall is essentially the rounded-down floor of the four with minor weighting — a single 9 sub-grade can still allow a 9.5 overall if the other three sub-grades are 9.5 or 10.
• CGC uses overall-only labels, with the same four-pillar logic as PSA, slightly more generous on edges in practice.
• SGC uses overall-only labels, with vintage-specific tolerances that are more lenient on age-appropriate wear.
• TAG shows you the exact point contribution from each pillar to the 1000 total — the most transparent of the five.

For a detailed comparison of how each service handles these pillars and why a BGS 9.5 isn't the same as a PSA 9.5, see card grading scales decoded.

Centering.

Centering is how the printed image sits inside the card's outer borders. Specifically, graders measure the proportional border width on each side of the printed inner frame. A perfectly centered card has equal border widths on left and right, and equal border widths on top and bottom — expressed as 50/50.

The further from 50/50 the card sits, the lower the centering sub-grade. PSA publishes their tolerances for each grade band; the other services use similar (sometimes slightly different) thresholds, but the underlying measurement is identical across all five.

PSA centering thresholds, approximately

• PSA 10 (Gem Mint): 55/45 or better on both axes — a tight tolerance window where the inner frame can be at most 10% off-center.
• PSA 9 (Mint): 60/40 or better — a meaningful but not severe shift.
• PSA 8 (Near Mint-Mint): 65/35 or better — visibly off-center but still presentable.
• Below PSA 8: Worse than 65/35, with the grade dropping based on the severity of the shift and any qualifiers (like “OC” for off-center cases that miscut at the factory).

Why centering is the most common cap

Centering is unique among the four pillars because it's set in stone the moment the print sheet was cut at the factory. Every other pillar — corners, edges, surface — you can preserve or destroy through how carefully you handle the card. Centering you can't change. The card either has it or it doesn't, and you have to take it as you find it.

This makes centering the most common reason a clean modern card caps at a 9 instead of a 10. The corners are sharp, the edges are clean, the surface is pristine — and then the centering measures 58/42 and the card caps at 9 regardless. There is nothing you could have done differently. The factory's cut wheel made the call back when the card was printed.

The one pillar you can verify before submitting:centering is a pure measurement, not a judgment call. Gemmr's centering checkmeasures both axes in seconds. If a card fails centering, no amount of submission strategy is going to fix that. Don't send centering-doomed cards expecting a different outcome.

Corners.

Each of the four corners is graded individually. A card with three perfect corners and one worn corner is held to the standard of its worst corner — the same weakest-link principle that governs the overall grade.

When graders look at corners, they're inspecting three things: sharpness (does the corner come to a clean point?), whitening (has the layered cardstock separated to expose the white inner ply?), and fraying or chipping. A perfect corner has all three attributes in their best state.

The four corner states

• Clean. Sharp point, no whitening, no fraying. The 10 standard. Looking at the corner under direct light from any angle reveals no defect.
• Soft. Minor rounding visible under direct light. No whitening yet. Caps the corner sub-grade at 9 in most services; the overall grade then depends on the other pillars.
• Whitening. White paper visible at the corner tip where the printed surface has separated from the inner ply. Caps at 8 or lower depending on the size of the whitened area.
• Damaged. Bent, chipped, frayed, or significantly worn. 6 or below depending on severity.

Why black-bordered cards are brutal on corners

Black-bordered cards — Pokémon V, VMAX, full-art trainers, many Magic editions, most modern sports parallels — are uniquely unforgiving when it comes to corners. The contrast between the black border and the white inner ply makes even microscopic whitening immediately visible. A modern Pokémon V with one whitened corner almost always caps at 9 even when everything else on the card is perfect, because the white shows up against the black border like a beacon.

White-bordered or light-bordered cards mask whitening much more effectively. The same level of corner wear that would cap a black-bordered card at 9 might pass on a white-bordered card and allow a 10. This is part of why grade rates differ so much across set design choices — the physical card construction interacts with the grading criteria.

What ruins corners after the pack

Corner damage is post-pack damage. The vast majority of corner wear happens between the moment a card leaves the pack and the moment it reaches the grader. The most common culprits:

• Sliding cards in and out of binder pages, particularly cheap binder pages with rougher edge tolerance.
• Penny sleeves that are slightly too tight — the sleeve corners catch the card corners and abrade them every time the card moves.
• Top loaders without a penny sleeve underneath — the card rattles inside the rigid plastic and abrades against the plastic corners.
• Carrying cards in a deck box where they shuffle against each other during transport.
• Storing cards in stacks without sleeves between them, where the corners of one card press into the surface of the next.

The minute-zero rule for preserving corner condition: penny sleeve every card you care about, then top-load anything you might grade. If a card spends more than a few seconds unprotected after leaving the pack, you've introduced corner risk that can't be undone.

Edges.

Edges are the four sides of the card, distinct from the corners. Graders look at edges separately because the failure modes are physically different from corners — you can have perfect corners and ruined edges, or clean edges and ruined corners. The two are not the same pillar.

What graders measure on edges: cleanliness (no nicks, chipping, or fraying along the cut), whitening (same separation issue as corners but along the length of the edge), roller marks (pressure marks from print rollers that appear as faint lines crossing into the edge), and factory cut quality (a poor factory cut leaves the edge slightly rough or irregular, which caps the grade even with no handling damage).

Common edge defects that surprise people

• Whitening along the length of an edge, not just at corner tips. Often visible as a thin white line running parallel to the edge for a few millimeters. Most common on black-bordered cards.
• Tiny nicks from being shuffled out of a deck. Cards played in actual gameplay accumulate small edge nicks that aren't visible until you hold the card flat at eye level.
• Roller marks crossing the edge. Faint indentations from the print roller that look like ghost lines on the card surface. Cap the edge sub-grade even when the rest of the edge is clean.
• Bad factory cuts. Some cards leave the factory with a slightly rough or asymmetric cut along one edge. This is unfixable and caps the edge sub-grade regardless of how carefully you've handled the card.

Corners vs edges — the common confusion

A common mistake is treating “corners and edges” as one thing. They're not. A card can have:

• Perfect corners and a chipped bottom edge — drops to a 7 or 8 because of the edge, not the corners.
• Clean top edge and a single whitened corner — drops to an 8 or 9 because of the corner.
• Both pillars in different states of wear — the worse of the two caps the grade.

When you're self-assessing, walk through corners and edges separately. Look at each corner individually, then look at each edge individually. Don't conflate the two, and don't assume that a clean corner implies a clean edge. They're physically adjacent but graded apart.

Surface.

Surface is everything happening on the front and back face of the card — scratches, print lines, indents, stains, holo wear, focus issues. This is the hardest pillar to self-assess because the defects only show up under specific lighting conditions, and most collectors never inspect their cards under those conditions before submitting.

Graders use a strong overhead light specifically designed to catch surface defects. They tilt the card under that light and look for everything ambient light hides. The same card that looks flawless on your desk under normal room lighting can show three faint scratches and a print line under a grader's lamp.

The five surface defects to know

• Scratches. Any visible scratch caps the surface sub-grade. A single faint scratch caps at 9; multiple scratches drop the grade further. Scratches on holo foil are particularly damaging because they're often invisible at one angle and obvious at another.
• Print lines. Faint parallel lines from the print rollers, often visible only on holos at specific tilt angles. Common on modern Pokémon (especially the V and VMAX product) and on modern sports parallels. Often unfixable because they're factory-introduced.
• Indents and dents. Small impressions in the cardstock, often from a fingernail, stylus, or pressure point. Hard to spot under direct light because the impression is shallow; obvious when the card is tilted because the indent catches light differently than the surrounding surface.
• Stains and discoloration. Yellowing from age, water marks, set-in fingerprints, ink transfer from adjacent cards in storage. Often catastrophic for the grade because stains can't be cleaned without damaging the card further.
• Holo wear. On holographic cards, scuffing of the foil layer creates dull patches where the holographic effect has been worn away. Essentially impossible to recover. Common on cards that have been handled with bare fingers or stored without proper protection.

Why surface is so hard to predict

Lighting is the entire game on surface assessment. Most collectors look at their card under ambient light — overhead room lighting, daylight from a window, the diffuse light on a desk. Ambient light is forgiving. It washes out faint defects and makes cards look uniformly clean.

Graders use raking light — a strong directional light at a low angle — specifically because it's unforgiving. Defects that hide at 90 degrees pop at 30 degrees. The same card that looks like a 10 to you might be a clear 9 to the grader because of three scratches you never saw under ambient lighting.

For a faithful self-assessment, tilt the card 30-60 degrees under a single bright light source — a desk lamp works fine. Look across the face of the card from a low angle. Whatever you see at that angle is roughly what the grader sees. If you find scratches, print lines, dents, or holo wear that weren't visible at normal lighting, you've just discovered why your card grade comes back lower than expected.

How to self-assess.

A quick four-step procedure for honestly assessing a card before submission. Following this catches roughly 90% of surprise grade outcomes — not because the procedure replaces a real grader, but because it forces you to look at every pillar separately and find the weakest one.

Step 1 — centering. Measure the borders with the edge of a credit card, a ruler, or a centering caliper. Compare left-to-right and top-to-bottom widths. Anything worse than 55/45 caps at a 9. Worse than 60/40 caps at 8. Worse than 65/35 caps at 7 or lower.

Step 2 — corners.Hold the card under a bright direct light. Look at each corner individually. On black-bordered cards, any white showing at the corner tip is whitening — cap at 8. On white-bordered cards, look for rounding or fraying of the corner point — cap at 9. A clean point with no rounding is the 10 standard.

Step 3 — edges. Hold the card flat at eye level and look along each edge in silhouette against a contrasting background. Chipping, fraying, or nicks will show as silhouette irregularities. Whitening on the edge shows as a thin white line running parallel to the cut. Clean silhouette and no whitening is the 10 standard.

Step 4 — surface. Tilt the card 30-60 degrees under a single bright light. Look across the face from the low angle. Scan for scratches, print lines, dents, and holo wear. A single faint scratch caps at 9. Multiple scratches or any of the other defects cap lower.

The most common self-assessment error is grading from above (the card flat under ambient light) instead of from the side (tilted under direct light). Side-angle inspection finds everything that overhead inspection misses. Get in the habit of running every card through the side-angle test before submission.

Quick FAQ.