Diamond proportion is one of the most important factors behind how a diamond looks in real life. It refers to the relationship between a diamond’s measurements, angles, and facet arrangement, all of which influence how well the stone handles light. For many buyers, proportion is the hidden reason one diamond looks lively and bright while another looks dull or uneven, even when both have the same carat weight.
If you are shopping for an engagement ring or comparing lab grown diamonds, understanding what is diamond proportion can help you make a better buying decision. Proportion is not just a technical grading concept. It directly affects sparkle, brilliance, fire, and how large or small a diamond appears face up.
In simple terms, good proportions help a diamond return light to the eye efficiently. Poor proportions can create dark areas, leakage of light, or a stone that looks smaller than expected for its weight. That is why proportion matters so much when evaluating diamond cut quality, whether you are looking at natural diamonds or lab grown diamonds.
Quick Answer: What Is Diamond Proportion?
Diamond proportion is the relationship between a diamond’s dimensions and facet angles. It includes measurements such as table size, depth percentage, crown angle, pavilion angle, and girdle thickness. These numbers work together to determine how the diamond interacts with light.
For buyers, proportion matters because it affects what you actually see. A diamond with balanced proportions is more likely to look bright, sparkly, and well-shaped. A diamond with poor proportions may leak light, appear dull, or face up smaller than expected.
In practical terms, diamond proportion is one of the main reasons why two diamonds with the same carat weight can look very different. It is also one of the most important things to understand when comparing cut grades, especially if you want the best visual performance for your budget.
What Diamond Proportion Means in Simple Language
Think of proportion as the diamond’s internal and external balance. A diamond is not judged only by how big it is or how clear it looks. It is also judged by how all of its parts work together. Those parts include the top facet, the lower facets, the overall depth, and the angles that guide light in and out of the stone.
When the proportions are well balanced, light enters the diamond, bounces around inside it, and returns to the eye as brightness and sparkle. When the proportions are off, light may escape through the bottom or sides instead of reflecting back. That creates weak performance, even if the diamond looks clean and polished.
This is why buyers often hear that cut is the most important quality factor for appearance. Strictly speaking, proportion is a major part of cut. It helps explain why one diamond can look more brilliant than another, even when color and clarity are similar.
How Proportion Differs From Shape
Diamond shape refers to the outline of the stone, such as round, oval, cushion, princess, or pear. Proportion refers to how that shape is cut and balanced. Two round diamonds can both be round, but one may have better proportions and therefore much better sparkle.
This distinction is especially useful for shoppers comparing diamond shapes. A round brilliant diamond is often evaluated differently from a fancy shape, but in every case, proportions still influence the visual result. That means shape alone does not tell you whether a diamond will perform well.
How Proportion Differs From Carat Weight
Carat weight measures how much a diamond weighs. It does not tell you how large the diamond looks or how well it performs. A diamond with strong proportions may look bright and well spread for its weight, while a poorly proportioned diamond may hide weight in depth and appear smaller.
This is one reason why experienced buyers do not focus on carat alone. A well-proportioned 1.5-carat diamond can look more appealing than a heavier stone with weak cut quality. If you want a deeper understanding of size versus appearance, it can help to compare proportion with diamond carat and diamond cut together.
Why Diamond Proportion Matters
Diamond proportion matters because it affects the three things most buyers care about most: beauty, performance, and value. Even if a diamond has excellent color or clarity, poor proportions can reduce its visual appeal. The reverse is also true. A well-cut diamond with strong proportions can often outshine a larger stone with weaker cutting.
From a buyer’s perspective, proportion is important because it affects everyday viewing conditions. Most people do not inspect diamonds in a gem lab. They see them under store lighting, indoor lighting, natural daylight, and sometimes in motion. Good proportions help a diamond remain attractive across those situations.
Proportion also matters because it can influence how much you need to spend for a diamond that looks impressive. In some cases, paying for better proportions gives a more noticeable upgrade than paying for higher clarity or a slightly larger carat weight.
Appearance
The first reason proportion matters is simple: it affects appearance. A diamond with balanced proportions usually looks brighter and more symmetrical to the eye. The face-up pattern is often cleaner, and the diamond tends to have stronger light return.
When proportions are poor, the effect can be easy to notice. The stone may have dark zones, a washed-out center, or a window-like see-through area. These issues can be visible without magnification, especially in larger stones or in diamonds with noticeable proportion problems.
Sparkle and Beauty
Sparkle is the visual effect created when a diamond reflects light in bright flashes. Proportion influences how much sparkle you see and how evenly it is distributed across the diamond. A well-proportioned diamond usually produces more pleasing, balanced sparkle.
Beauty is subjective, but proportion strongly affects how most people respond to a diamond at first glance. Many shoppers notice that some stones look crisp and lively while others look flat. That difference is often caused by cut-related factors, including proportion.
Value
Proportion matters for value because the market often rewards diamonds that perform well visually. Buyers are usually willing to pay more for stones with stronger cut performance, especially in round diamonds. However, there is also a point where the premium becomes less about visible improvement and more about grading preference.
That is why it is important to know when a proportion-related upgrade is worth paying for and when it is not. The answer depends on how visible the improvement is, what shape you are buying, and how the stone compares to other options in the same budget.
Key Proportion Measurements Explained
Diamond proportion is not one single number. It is a group of measurements and angles that work together. The most common ones shoppers encounter are table size, depth percentage, crown angle, pavilion angle, and girdle thickness. Understanding these terms can make diamond reports much easier to read.
Table Percentage
The table is the largest flat facet on the top of the diamond. Table percentage compares the width of that facet to the overall width of the stone. It helps indicate how the diamond will return light and how much of the top view is open versus faceted.
Why it matters: table size affects the balance of brightness, fire, and overall pattern. A table that is too large or too small can affect the stone’s visual personality and may reduce ideal light performance in some cases.
What buyers see: a table that is too large can sometimes create a flatter look, while a smaller table can contribute to more fire in certain diamonds. The effect is usually subtle unless the proportions are far from ideal.
Depth Percentage
Depth percentage measures how deep a diamond is relative to its width. It tells you how much of the diamond’s weight is hidden below the face-up view. Depth is important because it affects spread, light return, and the diamond’s apparent size.
Why it matters: a diamond that is too deep may carry extra weight where you cannot see it, making it appear smaller for its carat weight. A diamond that is too shallow may leak light or look watery and less lively.
What buyers see: depth problems are often visible as size inefficiency or weakened brightness. This is one of the more practical proportion factors because it can affect both appearance and value.
Crown Angle and Crown Height
The crown is the upper part of the diamond above the girdle, and its angle affects how light is dispersed. Crown height and angle influence fire, which is the colorful flash you see when a diamond moves.
Why it matters: a well-balanced crown helps create a pleasing mix of brightness and fire. If the crown is too steep or too shallow, the diamond may lose optical balance.
What buyers see: most shoppers do not measure crown angle directly, but they can notice whether the stone has lively flashes of color or looks flat in motion. The difference is often subtle in the store, but it becomes important in side-by-side comparison.
Pavilion Angle and Pavilion Depth
The pavilion is the lower part of the diamond below the girdle. Its angle is one of the most important factors in light return. If the pavilion angle is not well balanced, light can escape through the bottom instead of reflecting back to the viewer.
Why it matters: pavilion angle has a major effect on brilliance and leakage. In round diamonds, even small changes can make a noticeable difference in performance.
What buyers see: a poorly balanced pavilion may create a dark center, weak brightness, or an overall dull look. A well-balanced pavilion helps the diamond appear lively and sharp.
Girdle Thickness
The girdle is the edge around the diamond’s widest part. Its thickness affects durability and how efficiently the diamond’s weight is distributed. Extremely thin girdles can be more vulnerable to chipping, while very thick girdles can hide weight and reduce spread.
Why it matters: girdle thickness is important for both wearability and value. Buyers want enough durability for daily wear, especially in engagement rings, but they also want the stone to look as large as possible for its weight.
What buyers see: girdle issues are not always obvious at first glance, but they can affect how the diamond looks from above and how safely it can be set in jewelry.
How Diamond Proportion Affects Light Performance
Light performance is a practical way of describing how well a diamond handles light. It is the reason a diamond looks bright, sparkly, and lively. Proportion is one of the main drivers of light performance because it determines the angles at which light enters, bounces, and exits the stone.
When proportions are well balanced, the diamond usually returns a strong amount of light to the eye. This creates brilliance, which is the overall white light reflection, and fire, which is the colored sparkle created when light splits into spectral colors. It also affects scintillation, the pattern of light and dark flashes you notice when the diamond moves.
When proportions are off, the diamond may suffer from light leakage. That means some light escapes through the bottom or sides rather than reflecting back. The result is usually a duller, less lively appearance.
Brilliance
Brilliance is the diamond’s brightness. It is what makes a diamond look lively from a distance and under normal room light. Proportion is critical here because it determines how much light returns to your eyes.
What buyers notice: diamonds with strong brilliance often look crisp and bright even in moderate light. Diamonds with poor proportion can appear grayish, sleepy, or uneven.
Fire
Fire refers to flashes of color, usually seen as small rainbow-like bursts. Fire depends on the way light splits inside the diamond, and proportion influences how effectively that happens.
What buyers notice: fire is easier to see when the diamond is moving or under spot lighting. Some buyers love strong fire, while others prioritize a bright white look. Proportion influences the balance between those effects.
Scintillation
Scintillation is the pattern of bright and dark flashes you see as the diamond moves. It is one of the reasons diamonds appear lively instead of static. Good proportion creates appealing contrast and crisp flash patterns.
What buyers notice: well-proportioned diamonds often have a sharp, active sparkle pattern. Poorly proportioned stones may look splintery, too dark, or less dynamic.
Light Leakage
Light leakage happens when light passes through the diamond instead of reflecting back to the eye. It can occur because of incorrect pavilion angles, shallow depth, or other proportion issues. Leakage weakens the diamond’s visible brightness.
What buyers notice: leakage may appear as transparent areas, dark patches, or a lack of life in certain viewing angles. In some diamonds, it is only obvious when comparing stones side by side. In others, it is easy to spot immediately.
Diamond Proportion and Cut Grade
Cut grade is the formal assessment of a diamond’s overall cut quality, and proportion is a major part of that assessment. In round brilliant diamonds, the cut grade often reflects how well the proportions, symmetry, and polish work together. In fancy shapes, grading systems may be less standardized, so proportion becomes even more important to evaluate carefully.
Many shoppers assume that a high cut grade automatically guarantees the most beautiful stone. That is often a good starting point, but it is not the full story. Two diamonds with the same cut grade can still look different because proportion ranges, facet precision, and optical symmetry are not identical in every stone.
This is why buyers should use cut grade as a screening tool, not the only decision point. If you are comparing lab grown diamonds, the same advice applies. The grading report helps, but the actual visual performance should still be considered.
Excellent Cut Versus Very Good Cut
For many buyers, the most practical question is whether an Excellent cut diamond is visibly better than a Very Good cut diamond. The answer depends on the exact stone, but the difference is often noticeable in side-by-side comparison and less obvious when viewed separately.
An Excellent cut stone is more likely to have balanced proportion and stronger light return. A Very Good cut stone can still look attractive and may offer better pricing. If the proportions are strong, the difference may be subtle in everyday lighting. If the proportions are weaker, the difference can become easier to see.
Ideal, Excellent, and Premium Labels
Retail terms like Ideal, Excellent, and Premium are not always standardized across sellers. Some are tied to lab grading systems, while others are marketing labels. This is why buyers should always look beyond the name and review the actual proportion data when possible.
A diamond labeled Ideal by one seller may not be identical to another seller’s Ideal stone. The safer approach is to ask what proportions, optical results, or lab grades support the label.
How Diamond Proportion Affects Appearance in Real Life
The best way to understand proportion is to think about what you will actually see in normal use. Diamonds are worn in mixed lighting conditions, not controlled lab conditions. That means the real test is how the stone performs in stores, restaurants, offices, daylight, and home lighting.
Good proportion usually leads to a diamond that looks lively from more angles and in more environments. It tends to hold its brightness better when the stone moves, and it is less likely to appear dark or lifeless in the center. This is especially important in engagement rings, where the diamond will be seen frequently and closely.
Poor proportion can lead to several visible problems. The diamond may look too flat, too deep, or oddly proportioned from the top. It may also look smaller than expected, even if the carat weight is impressive.
Face-Up Size
Face-up size is how large the diamond looks when viewed from above. A well-proportioned diamond can appear larger than a heavier but deeper stone because more of its weight is distributed across the top. This is especially important when comparing diamonds with similar carat weights.
Buyers often find this surprising. A diamond that is heavier on paper does not always look larger in a ring. Proportion strongly influences spread, so it can affect the sense of value.
Symmetry of Light and Dark Areas
When a diamond is viewed face up, it should ideally show an attractive balance of bright and dark areas. This contrast is part of what creates sparkle and life. Proportion helps shape this pattern.
If proportions are off, the pattern may look uneven. You might see a dark center, a watery effect, or irregular patches. These are not always dramatic flaws, but they can reduce the overall beauty of the stone.
Motion Performance
Diamonds are rarely still in daily wear. They move with the hand, and that motion is part of what creates sparkle. Proportion affects whether that movement produces sharp flashes or a duller appearance.
What buyers often notice in person is that some diamonds “wake up” when they move, while others stay visually quiet. That difference is usually connected to how well the proportions support light performance.
Practical Examples Buyers Can Relate To
Well-Cut 1.5-Carat Diamond Versus Poorly Cut 2-Carat Diamond
This is one of the most useful comparisons for buyers. A 2-carat diamond sounds more impressive on paper, but if the proportions are poor, the stone may look dull, deep, or smaller than expected. A well-cut 1.5-carat diamond can often look brighter and more attractive because it reflects light better.
In everyday viewing, many people would prefer the livelier stone, even if it is smaller by weight. This is a common example of how proportion can outweigh carat in real-world appearance.
Excellent Cut Versus Very Good Cut in Normal Lighting
In a jewelry store, the difference between Excellent and Very Good cut may be subtle if both stones are strong performers. Under everyday lighting, both can look appealing. However, when compared side by side, the Excellent cut stone often shows a cleaner pattern, better brightness, or more balanced sparkle.
For buyers on a budget, a carefully chosen Very Good cut diamond may still be a smart purchase. The key is to inspect the actual proportions and ensure the diamond does not suffer from visible performance issues.
Higher Clarity With Poor Proportion Versus Lower Clarity With Excellent Proportion
Some buyers focus heavily on clarity because they want a flawless-looking diamond. But if the cut is weak, the diamond may not look beautiful even with high clarity. In contrast, a lower-clarity stone with excellent proportion can often appear more attractive because light performance masks minor inclusions and creates more visual impact.
This is why experienced buyers often prioritize cut first. Clarity matters, but it is usually less visible than proportion-related sparkle and brightness unless the inclusions are obvious.
How Proportion Varies by Diamond Shape
Proportion matters in every shape, but the rules are not identical. Round brilliant diamonds have the most widely standardized cut evaluation, while fancy shapes such as oval, pear, cushion, and emerald require more visual judgment. That makes shape an important part of the buying process.
Round Brilliant
Round brilliant diamonds are generally the most forgiving and the most studied for cut performance. Proportion has a major impact on brilliance, fire, and symmetry. Buyers can often rely on cut grade, proportion ranges, and optical tools more confidently with round stones.
This is why round diamonds are often the benchmark for cut quality discussions. If you are comparing round stones, proportion should be near the top of your checklist.
Oval, Pear, and Marquise
Elongated shapes can be beautiful and face up larger for their weight, but they also make proportion evaluation more complex. Bow-tie effects, uneven brightness, and shape-specific light leakage are common concerns. Proportion still matters, but the ideal measurements are less standardized.
What buyers should watch for is visual balance. The diamond should look bright and even across its length, without obvious dark zones or unattractive windowing.
Cushion and Princess
Cushion and princess cuts can have different facet styles that influence how they handle light. Some cushion diamonds have softer, more romantic sparkle, while princess cuts often show a sharper flash pattern. In both cases, proportion helps determine whether the stone looks lively or overly dark.
Because these shapes vary more in design, buyers should rely less on a single number and more on actual visual inspection or trusted grading information.
Emerald Cut
Emerald cut diamonds are known for their step-cut look, which emphasizes clarity and transparency more than sparkle. Proportion matters differently here. Instead of intense brilliance, buyers should look for attractive window placement, balanced depth, and a clean hall-of-mirrors effect.
In an emerald cut, a “good” proportion may be one that creates a sleek, elegant appearance rather than maximum sparkle. This is a good reminder that proportion supports different visual goals depending on the shape.
Lab Grown Diamonds and Proportion
Lab grown diamonds follow the same optical principles as natural diamonds. That means proportion matters just as much, and sometimes more, because many lab grown buyers are shopping for maximum visual performance at a lower price point than comparable natural diamonds.
One practical advantage of lab grown diamonds is that buyers may have more budget flexibility to prioritize cut quality. Since lab grown diamonds typically cost less than natural diamonds of similar appearance, some shoppers choose to put more of their budget toward a superior cut proportion and a stronger overall visual result.
That said, the same trade-offs still apply. Not every lab grown diamond is well cut, and not every attractive-looking stone has perfect proportion data. Buyers should still evaluate cut, symmetry, and light performance carefully.
Why Proportion Still Matters in Lab Grown Stones
Some buyers assume that because lab grown diamonds are modern and precise, cut quality is always excellent. That is not true. Lab growth creates the crystal, but the cutting process still determines the final proportions and optical behavior.
A lab grown diamond with weak proportions can look less impressive than a carefully cut natural diamond. So if you are comparing lab grown diamonds, it is still important to review cut grade, proportions, and overall visual performance.
Value Considerations for Lab Grown Diamonds
Because lab grown diamonds often have lower upfront prices, some buyers expect to compromise less on cut. In many cases, that expectation is reasonable. However, price alone does not guarantee quality.
For long-term satisfaction, it often makes sense to compare a few lab grown stones with different proportions rather than choosing the biggest option. A smaller but better-proportioned diamond may look more refined and more brilliant in the finished ring.
Advantages of Good Diamond Proportion
- Better brightness and light return.
- More attractive sparkle and scintillation.
- Better face-up appearance for the carat weight.
- Less risk of visible dullness or light leakage.
- Often stronger overall value from a visual standpoint.
- More consistent performance in everyday lighting.
These advantages are especially noticeable when comparing diamonds in person. Even buyers who do not understand the technical details often respond more positively to a stone with balanced proportions because it simply looks more alive.
Disadvantages and Trade-Offs
- Better proportion can come with a higher price.
- Cut quality is not always obvious from a report alone.
- Ideal-looking proportions may still vary by shape and style.
- Some stones with excellent proportions may look smaller than deep stones of the same carat weight, depending on design.
- Fancy shapes can be harder to evaluate consistently.
It is also worth noting that “best” proportions are not always the same for every buyer. Some people prefer a diamond with more fire, while others want a brighter, whiter look. Others may prioritize size or budget and accept a slightly lower cut performance.
Buying Considerations: How to Evaluate Diamond Proportion Wisely
If you are buying a diamond, the best approach is to treat proportion as one part of the full picture. Start with the shape, carat range, budget, and setting style, then examine cut-related data carefully. For many shoppers, the easiest path is to narrow choices using certification and then compare the actual visual appearance.
Start With the Certificate
A reliable grading report can give you the proportions and cut-related details you need to compare stones. For round diamonds, this may include cut grade, table percentage, depth percentage, symmetry, and polish. For lab grown diamonds, the report is equally useful because the stone still needs to be evaluated on the same optical principles.
Certificates do not replace your eyes, but they help filter out weak performers. Learning how to read diamond certifications can save time and reduce the chance of overpaying for a stone that looks less impressive than it should.
Compare More Than One Diamond
One of the best ways to understand proportion is to compare stones side by side. Differences that seem small on paper can become obvious in person. A diamond with strong proportions may look noticeably brighter and more balanced than another stone with a similar size and price.
If possible, compare diamonds under different lighting conditions. Store lighting can emphasize sparkle, while softer lighting reveals whether the stone maintains brightness and contrast.
Do Not Rely on Carat Alone
Carat weight is easy to understand, which is why many buyers focus on it first. But proportion often has a bigger impact on daily appearance. A slightly smaller diamond with better spread and stronger light return may look more impressive than a heavier diamond with poor performance.
This is one of the most common and expensive mistakes in diamond buying. The number on the scale is not the same as visual beauty.
Balance Proportion With Color and Clarity
Once cut quality is strong, you can make smarter decisions about color and clarity. Many buyers can choose a slightly lower clarity grade or a slightly warmer color if the diamond has excellent proportions and looks lively. That trade-off often improves overall value.
This is especially true with lab grown diamonds, where the budget advantage may allow you to choose a high-performing stone without sacrificing too much elsewhere.
Pay Attention to the Setting
The ring setting can influence how proportions appear in the finished piece. A setting with an open gallery may show more of the diamond’s profile, while a bezel can change the visual perception of size and brightness. The setting does not fix poor proportions, but it can affect how the diamond looks once mounted.
If you are shopping for engagement rings, it is worth considering the diamond and setting together rather than separately.
Common Buyer Mistakes
Prioritizing Carat Over Cut
Many buyers assume a larger stone is automatically the better choice. In reality, size without good proportion can leave you with a diamond that looks less lively than a smaller alternative. This mistake is common because carat weight is easy to compare, while proportion requires more attention.
Overpaying for Clarity
Clarity becomes less important when a diamond has strong brilliance and sparkle. Many inclusions are hard to see without magnification, especially in well-cut stones. Buyers often spend more on clarity than necessary and then overlook proportion, which has a bigger visual effect.
Ignoring Light Performance
Some shoppers focus only on numerical specs and forget to look at how the diamond behaves in light. This can lead to disappointment. A stone with acceptable measurements on paper may still look flat or dark if the proportions are not well balanced.
Assuming All Diamonds Sparkle Equally
Not all diamonds have the same optical performance. Sparkle depends on how the diamond is cut, not just on whether it is a real diamond. A well-proportioned diamond can look dramatically more appealing than one with weak cut quality.
Not Checking Fancy Shapes Carefully
Fancy shapes can look beautiful, but they vary more in proportion and light return. Buyers who assume the same rules apply to every shape may miss bow-tie effects, windows, or uneven brightness. Shape-specific evaluation is especially important for oval, pear, and emerald cut diamonds.
Frequently Asked Questions
Is diamond proportion the same as cut?
Not exactly. Cut is the broader category, and proportion is one of the main parts of cut. Cut also includes symmetry, polish, and overall light performance. Proportion tells you how the diamond is shaped and angled, which strongly affects how it looks.
Can a diamond with good proportion still have weak sparkle?
Yes, although it is less common. Other factors such as symmetry, polish, facet precision, and shape-specific design can also affect sparkle. In fancy shapes, visual performance can vary even when proportion data looks acceptable.
Do buyers actually notice proportion differences without training?
Often yes, especially when comparing diamonds side by side. People may not know the technical reason, but they can usually tell when one stone looks brighter, more balanced, or more lively than another. The difference becomes easier to notice when proportions are clearly better or worse.
Is there one perfect proportion for all diamonds?
No. The best proportions depend on the shape, cutting style, and desired appearance. Round brilliant diamonds have the most standardized expectations, but fancy shapes are more variable. That is why proportion should be evaluated in context rather than by one universal number.
Should I pay more for a diamond with better proportion?
Often yes, if the visual improvement is meaningful and fits your budget. Paying more for proportion can make sense because it improves the diamond’s beauty in everyday wear. However, the premium should be justified by a noticeable difference in appearance, not just a better label.
How can I tell if a diamond has bad proportion?
Look for signs such as dullness, a dark center, transparent areas, or a smaller-than-expected face-up appearance. A grading report may also show unusual table, depth, or angle measurements. If possible, compare the stone directly with a better-performing diamond.
Does proportion matter more in natural or lab grown diamonds?
It matters equally in both. The physics of light do not change based on how the diamond was formed. Lab grown diamonds may offer more budget room for better cut quality, but the importance of proportion is the same.
Can a diamond be too perfectly proportioned and still not suit me?
Yes, because personal preference matters. Some buyers prefer more fire, some want a bright white look, and some care most about size. A technically strong diamond is usually a good starting point, but the best choice still depends on your taste and priorities.
Practical Takeaways for Buyers
If you are trying to understand what is diamond proportion, the simplest answer is that it is the balance of a diamond’s measurements and angles, and that balance has a direct effect on how the stone looks. It influences brightness, sparkle, fire, and how large the diamond appears for its weight.
For most buyers, proportion is one of the smartest places to focus attention because it has a bigger visual impact than many other grading factors. A well-proportioned diamond often looks more beautiful, more lively, and more valuable in everyday use than a larger stone with weaker cut performance.
The best buying approach is to use the certificate as a guide, then judge the actual visual result. If you compare stones carefully and prioritize proportion along with cut quality, you are more likely to choose a diamond that looks impressive in real life, not just on paper.
