Оцінка артефакту

Важливість сертифіката автентичності
May 1, 2017
  • Task Artifact Evaluation

Anyone who buys artifacts without knowing how to evaluate them is more apt to make a bad investment than a good one. There are more replicas on the market than one could even imagine and many of them are difficult to distinguish from originals. Collectors with years of experience protect themselves by an instinct and familiarity along with well-documented facts.

So, how can a beginner hope to get into a business where even experts get conned? The answer is a methodical approach to analysis. Several indicators allow objective evaluation and a apparent level of certainty.
Archaeological materials are, by their nature, non-renewable resources. Aimless collecting destroys contextual information about how the tool relates to the rest of the culture. A number of laws are either already on the books or are planned to discourage commercialization of ancient materials.
Five sets of indicators allow an exhaustive evaluation of an artifact:

AGE – the question of age is simply whether the work is modern or ancient. Of course the older the artifact, the more difficult it is to locate the best examples of the period.

  • Freshness – of flake scars is really an impression conveyed by a number of factors. Even a novice can recognize recent scars when nothing has been done to disguise them. Depending on the environment that the artifact ages in, it may undergo subtle or major changes in appearance. Inventive fakers can create environments that greatly accelerate normal processes. Acids, oils, tumbling, or sandblasting can all mask the distinctive, crisp appearance of new work.
  • Deposits – the most common means of mimicking the appearance of age is to coat the surface with a deposit of stain or soil. Artifacts with authentic deposits depend on special environments for their formation. Coatings that can be brushed or washed off are apt to be recent additions. It pays to be familiar with deposits common to where the artifact supposedly came from. Ancient deposits are usually mineral encrustation or dirt caught in protected depressions. You should be suspicious of uniform coatings, especially when the high spots show wear through the coating. Such selective wear is not consistent with normal erosion. One deposit that cannot be faked is lichen growth. It takes more years to grow than a dealer has time for.
  • Patination – is difficult, but not impossible, to duplicate. Acid can be used to etch the surface, resulting in a shallow, white shell. Oil or water darkens artificial etching, but not the naturally altered surface. Any damage after patination started will show as a difference in tone. Usually, it will be most pronounced on one face. Some stones, although perfectly solid and workable, may have zones that erode severely as pits and spongy looking areas. Don’t forget that to patinate, the artifact had to be exposed to other means of alteration, like abrasion. Obsidian patinates by taking on water at a rate and depth controlled by temperature and humidity. Sometimes you can see the layer by transmitted light, without having to break or saw the stone to prove age. Hung flakes tend to patinate more quickly than the rest of the surface.
  • Hung flakes – freshly flaked surfaces virtually always have remnants of flakes still adhering. Hung flakes on unweathered, unsoiled artifacts are easy to see because they catch light and appear lighter than the rest of the stone. Years of thermal expansions and contractions, plus water and abrasion will remove all but the most tightly attached flecks of stone. The bits that stay in place trap dirt, blood, and stains. Check an artifact by lightly picking at hung flakes to see if they are barely attached. Don’t get too critical, however, there will usually be some flakes remaining. Also examine the remaining dirt or stain to see how well affixed it is. Attempts to pick the flakes off mechanically often leaves metal stains or bulbs of pressure on the face where they shouldn’t occur.
  • Wear – few artifacts pass their existence in pristine storage conditions. Forces of erosion, use, and shifting in the earth eventually cause varying degrees of wear on prehistoric tools. If the tools were carried in a bag, they can have polish marks on high spots. Cached tools typically show bag wear. Artificial wear can often be spotted with a little common sense. Check to see if hafting areas are free of use-marks. Watch for modern work that has been tumbled or sanded, it has wear different from most real artifacts. Sand and water polish is distinctive and difficult to reproduce. Compare wear on edges to the wear on faces to see if it is in line with the advertised history of the artifact.
  • Use damage – artifacts were made to be used. Look at edges for signs of use: cutting, scraping, polish, impact, and so forth. Faces can show evidence of hafting. Damage from use is usually specific to portions of edges or faces. Since collection values decline with damage, you don’t see much deliberate damage on modern work. Plows leave distinctive gouges and rust stains on artifacts from cultivated fields. Other damage that occurs well after the artifact is lost may help you identify the degree of patination or weathering that has taken place.
  • Re-use – primitive people typically used tools for a continuing variety of tasks. The re-working and re-shaping necessary for adapting to different use leaves distinctive patterns of flake scars. Most modern reproductions represent artifacts that would have been lost without having been put into service. That is what makes them desirable to collectors and it also should raise the collectors suspicion. Repair of damage or conversion of use is often detected by changes in profile or contour. Edges, for example, may be retouched only away from the hafting, and retouch may extend only part way to the center, leaving a visible bevel.
  • Texture – either physical or chemical erosion can change the texture of an artifact over time. Sometimes the surface can become slick and sometimes it roughens. It helps if you can obtain samples of the stone that demonstrate both aged and pristine surface appearances. Some archaeologists are assembling good reference collections so you might not have to create your own.

TOOLS – workers of flint used tools dictated by the culture they were part of. Characteristic flake scars help to identify what tools were used to make a particular artifact. Modern tools, not available to early cultures, create an appearance different from original work. It may be helpful to consider whether artifacts indicate representative or unusual use of tools.

  • Metal marks – metal tools were rarely used in early times, and the marks would normally be gone by now. When you see metallic deposits on an artifact, it is probably a reproduction. Metal marks are most apt to be in notches, around hung flakes, and adjacent to bulbs. A skillful knapper will not leave metal marks and a determined faker can remove them anyway. Collectors need to know that Archaic Indians used some copper tools in the Mississippi Valley, as did makers of parallel-flaked knives in Denmark and Egypt.
  • Bulbing – tool hardness influences the way a bulb forms at the start of a flake. The harder the tool, the more distinct the bulb. If the tip of the tool is sharply pointed, a distinct bulb can be made in spite of how hard the tool is. Soft tools wear so quickly that most craftsmen won’t take the effort to keep them sharp. Combined with other clues, bulbous scars can indicate the use of metal tools.
  • Ripples – as a fracture progresses, ripples on the scar surface reveal the history of forces that promote the flake. Some of the effect is caused by varying cross-sections as the fracture passes below rises and dips in the surface that is being taken off. Collapse of the platform and the tool during impact also contribute to rippling. When ripples are distributed evenly along the flake, the force is uniform throughout the time of fracture. Changes in ripple distribution reflect changes in force. Ripples near the bulb reveal that initiating forces are most prominent, as in hard hammer percussion flaking. Pressure flaking and soft hammer techniques encourage ripples to be noticeably more pronounced near the end of their travel. Dips in trajectory occur when forces increase. When the load is released, the trajectory rises. Flakes on flat slabs tend to ripple heavily and have diving terminations.
  • Lipping – when the tool overlaps the edge of the preform, it can cause a “lip” to form at the leading edge of the flake. Lipping indicates the use of soft tools because they are most likely to distribute force in the way that causes this particular form of fracture. Hard tools can create the same effects, but not as readily. The frequency of occurrence has to be taken into consideration when evaluating lipping.
  • Tear lines – the magnitude of applied force can sometimes be seen in tear lines. Tear lines occur at the edge of a flake when critically stressed surfaces do not line up because fracture develops before the stress can distribute evenly. You can see the effect in any stone, but perhaps most strongly in tough stones. Tear lines are most important for the environment they create for deposits and patination.
  • Scar size – You can make some rough judgment as to what tools were used, based on the size of flake scars. Percussion flakes may be small, but they are usually larger than pressure flakes. Some methods of pressure can create scars that are quite difficult to distinguish from percussion. Additional clues of ripples and bulbs help in deciphering tool use.

STYLE – an artifact was built to serve a function, and that function guided its form. Standard typology uses geometry and dimension to take measure of form without recognizing the reason for the form. Some collectors’ value classic shapes while others look for the atypical. Relatively low availability of a particular style is called rarity.

  • Shape – are normally described through geometric terms. The presence or absence of symmetry is important to note. Arcs, proportions, and how elements relate to each other are all important. Usually, hafting elements are described separately from elements with another function.
  • Profile – is considered separately from a plan view, because it sometimes is the critical difference between work by different cultures. Taper is important to function, as is balance and uniformity. A thick, robust tool performs differently than a thin, delicate tool. The cross-section often reveals the standards of the maker.
  • Standards – a difficult but important question is “What was the worker trying to achieve?” Aboriginal standards are not well known, but the more samples that we can observe, the better we understand what deviation was acceptable. Sometimes artifacts were discarded because they could not be made to fit the standards of the craftsman. What archaeologists consider “classic” forms are not necessarily what a culture may have considered as the norm.
  • Dimension – measurements are important and there are a number of ways to apply them. Absolute dimension is a straightforward comparison to a scale. Relative measurements determine if one artifact is bigger or smaller than another. Maximum and minimum values as well as averages and means can describe sets of data. Modern knappers like to make things bigger than life, and collectors buy into the premise as well.
  • Hafting – since hafting is tied to function, it is important to attend to how far the hafting extends, what design was chosen? Is the hafting element symmetrical? Is the hafting refined with deep, thin, or curved notches? You will only be completely sensitive to hafting if you try to affix a stone tool to a haft. It is not as simple as it seems.
  • Retouch – the amount of retouch on a tool is partly a matter of cultural habit, but it is also a measure of tool use and rejuvenation. Pay attention to the extent of retouch. Is it careful or not? Is it bifacial or unifacial? How big are the retouch flakes? Are they kept in control?
  • Rejuvenation – tools are typically thought of as the only phase that the tool will exhibit. Primitive people rarely allowed a tool to go out of circulation without giving it some wear and subsequent alteration, sometimes many times over. Typologists have realized that what were once considered separate types are sometimes altered versions of the base form. Look for indications of previous stages, evidenced by changes in scar type or size. Often you can see a break in shape or profile caused by rejuvenation.
  • Edge grinding – edges were ground for many reasons. Sometimes grinding remains from the manufacturing stage. Hafting elements are often ground to protect bindings. The degree of grinding should be considered, along with extent and the manner of application.
  • Stone type – a collector should be familiar with the stone used by the culture in question. Some stone sources are customary; some are known as variations from the norm. Distance from the source of stone can reveal movement of peoples or trade patterns. Colors, patterns and inclusions help in categorizing stone types. Appearance of the stone can add considerable weight to aesthetic value.Modern knappers often use stone saws to get larger pieces of unusual stone than primitive people normally used. Outlandish artifacts are not automatically fakes, but they should be scrutinized especially thoroughly.

STRATEGY – is the mental part of knapping. It reflects the craftsman’s order of business. Some workers were very organized in their approach; others seemed to have no system.

  • Sequence – each culture and each knapper had a strong preference for how they selected the next flake to be removed. Some of the most highly valued artifacts have highly organized patterns of flake scars. They can be serial, skip at regular intervals, or be applied alternately edge-to-edge or face-to-face. Most generally, the flakes were selectively removed in no obvious pattern.
  • Flake spacing – whether flakes were closely spaced or wide apart depends on the knappers preference or the tools at his disposal. Look at the variation in spacing. Uniform spacing is deliberate and controlled. Rejuvenation can change flake spacing, particularly if another person does the next phase of work. Often, each stage of work has a characteristic spacing.
  • Edge preparation – a tool is only as good as its working edges. Edges that have haphazard treatment are suited to limited tasks. The more carefully the edge is treated, the more you can assume the task to be performed by the tool effects the knappers effort. Beveling and grinding or wear can tell a lot about how a tool was used.
  • Earlier stage – whatever remains of an earlier stage is an integral part of the “look” of a tool. More importantly, it is an indication of the craftsman’s’ progress. To recognize distinct stages, there must be a change in strategy or a change of tools. Complete obliteration of an earlier stage can also be significant. Ancient cultures were very consistent in moving from one stage to the next. When an artifact fails to fit the normal pattern, questions should be asked as to “why?”
  • Platforms – where the craftsman places a blow probably controls the outcome of a flake more than any other variable. Look for evidence of deliberate structure. Occasionally, the whole edge will be beveled as a continuous platform. Individual platforms are more common. The most careful work is on isolated platforms. When the right surface just happens to be there, however, it gets used. In spite of the importance of platforms, they are extremely difficult to examine because they seldom stay with the tool.
  • Flake orientation – you can tell much about how a knapper planned ahead by observing flake orientation. Consistent orientation indicates a very structured approach. Flake scars may all slant uniformly, intersect in a chevron, or be radial to the center. Each results from a deliberate design. Unorganized scars do not necessarily reflect any less skill, but each flake was planned for individual effect. Flake orientation has a great deal to do with aesthetic value.

TECHNIQUE – the mechanics of flintknapping are techniques. Primitive lifestyles had little room for alternate ways of using tools. You were expected to perform as your ancestors had—it was a matter of survival. Another aspect of technique is the degree of control that could be achieved. Modern work faces the test of whether it is representative (image), or if it is a replication (follows original rules).

  • Fracture trajectory – a knapper’s skill in making a fracture occur just where it is wanted can be accurately evaluated by looking at the trajectory of a flake. Is it arced or flat? More importantly, how consistent is it? You don’t need to be a knapper to recognize good work.
  • Scar geometry – the balance of forces acting to remove a flake is revealed in the scar geometry. Strong outward forces tend to expand flakes, while parallel sides often reflect good balance. As usual, pay attention to how consistent the knapper was. Also take into account the way one flake overlaps another. When scars are all precisely alike, you must decide if you are dealing with extremely high skill or if the preform was ground to shape before the final series of flakes were made.
  • Terminations – of all the parts of a flake scar, terminations are most apt to survive because they are usually at the center of the tool. An ideal balance of forces is revealed by smooth, feathered terminations. When forces are not in good control, you may see wavy terminations. Diving terminations are a sign of bending or highly compressive force. As was noted earlier, flaking on sawn stone slabs tends to cause diving terminations. Loss of compressive force often causes a flake to hinge to the surface. Be a careful observer to determine which scar overlaps another.
  • Heat treatment – modern improvements in flaking quality by heat-treating tend to be too severe. Highly glassy alteration allows perfect control over flakes, but it also makes the stone tool vulnerable to damage. Ancient heat-treating was designed to make the stone workable, without harming its function. Severe treating equates to fragility. Don’t assume that high gloss must mean you are looking at a replica. Just be sure to correlate all the evidence before you judge.
  • Ripples – point out the direction of forces that caused a fracture. For one thing, they arc away from the point of impact. For another, they rise and fall as forces act toward and away from the surface. Characteristic amplitude and frequency of ripples is usual for unique combinations of tools and techniques. Compare what you see on a stone tool with other pieces to determine if it seems to be appropriate.
  • Grinding – is expected on hafting portions of paleo-period projectile points, but can be out of place on other styles. Learn what is normal. Remnants of platform grinding may help to confirm the technology used. Remnants of ground or sawn faces, however, are a tip-off of modern shortcuts.
  • Reproduction – when a knapper is concerned with results but not with means, the result is a reproduction. The product will be similar to the original pattern in image, but will differ in many important ways. Noticeable discrepancies range from thickness and profile to flake scar patterns. Reproductions often use eye-catching materials.
  • Replication – if the original process is re-created, the product is a replica. The accuracy of the process determines how well the original pattern is matched. It is possible to make tools that are extremely accurate representations of a culture. Many knappers inscribe their initials, but many do not. Replications of distinctive, attractive point styles are most common.
  • Teleolithics – some modern knappers are interested in using modern tools and techniques to extend beyond where ancient knappers left off. Teleolithics is a term coined to describe this extrapolation of lithic technology to its highest level. Very beautiful effects can be created by heat treating the finest stone and using every technical advantage. Usually, there is only a superficial design tie to prehistoric predecessors. The best of teleolithics is high art.

RESTORATION – many broken, authentic artifacts are so intriguing that a collector restores the missing parts, so the original condition can be enjoyed. If the restoration is done correctly, the result is educational. If someone buys a restored point without being aware of its real condition, it can be considered fraud.

  • Re-joining broken artifacts – careful collectors can frequently find conjoining pieces of an artifact. When they are glued back together, the value is only slightly reduced from the intact version. Ancient breaks usually were caused by use and you can expect predictable patterns of breakage. Stems snap in a certain way because of how they were hafted. Minor tip and ear damage is rarely recovered and may indicate recent damage—a careless viewer? Does the history of the artifact support what you see?
  • Epoxy build-ups – the very best restorations use epoxy resin that is stained to match color and texture of the original artifact precisely. Usually, only small nicks, missing tips, or ears are replaced. Occasionally, the bulk of the “artifact” can be new. Black light can be used to reveal this kind of modification.
  • Add-ons – it is possible to find stone that matches the artifact, and knap a replacement part. When it is done carefully, the join can be nearly impossible to see. In this case, even if you see the join, it appears to be a legitimate repair. The only way to recognize this kind of alteration may be to unglue the added piece and check for grinding or other signs of mis-match.

YOUR INSURANCE POLICY – don’t collect in a vacuum. The most successful collectors network effectively to protect themselves from unscrupulous behavior. With the advent of the Internet, you have access to a wide array of advice on an instant’s notice. Just be prepared for conflicting opinions. Think of it as having a board of directors and you, as the Chairman, have to make the final decision – and live with it.

  • Context – the better you know where, when, and how the artifact was collected, the better you can answer other questions about it. All other factors being equal, highest values go to artifacts with a known history. Best of all is a scientifically controlled and documented dig. Since you are not buying that kind of artifact, you must rely on other forms of documentation. Is the artifact pictured in an old publication? Can you find people that swear they saw the artifact where it was found, or can at least vouch for it being from a particular area? Watch out for biased parties. It is of little assurance that the seller’s best friend swears by the artifact. Avoid collecting something that has an illegal past. You don’t want to have your collection busted by the Feds.
  • Familiarity – comfort comes with familiarity. Familiarity comes with time and experience. Since you probably don’t want to wait for years, you need to find another way to get up to speed. One approach is to visit museums and old collections, read books, and buy casts of proven artifacts. Another method is to rely on advice from folks who have handled artifacts from the region in question for years. When artifacts are out of place with collections from the area they are reputed to come from, it should set your nerves a-tingle.
  • Technical knowledge – knappers know the most about how stone artifacts were constructed. I know some of you consider them the enemy, but that is an irrational excuse for not learning something about the process of flaking stone. Knap-ins abound in every region of the country. You don’t have to buddy up to knappers to learn from them, and you may be pleasantly surprised at what you learn.
  • Authentication – second opinions come in many flavors. Anyone can write an authentication, but only a few have the experience and reputation to go virtually unchallenged. Don’t consider an authentication from the seller as being worth anything. Reputable sellers shouldn’t mind giving you time to run an artifact by a second, or even a third expert appraisal (at your expense, of course) before money changes hands. Learn from the experts. They want to know the presumed history of an artifact before they pass judgment on it.
  • Price – keep in mind the old advise about things that are too good to be true, since they usually are. But be just as wary of the highest price. Even the most moneyed collectors can relate some bitter experiences. The come-on, that the seller is too naive to recognize the true value of a good-looking artifact, can lower your defenses—watch out for avarice. If you think this is a good way to invest, you are probably mistaken. Make your judgments of monetary value on your personal sense of what an artifact is worth. Above all, look for a money-back offer. If it really is a good deal, neither the buyer nor the seller has anything to lose.

HOW DOES IT ALL ADD UP?

By assigning a numerical value to each indicator, you can create a score to rate any flaked artifact in comparison to another. Since individual collectors have individual motivations, they should set their own ranking. The purist who rates modern work is free to set a value of zero for no age, but will find that other indicators reveal comparative merit. Regardless of how individuals set values, they should be consistent in their own rating.

Monetary value of a collectable item is determined by supply, demand, and perhaps most importantly, intensity of interest. No system can completely protect the person who collects as an investment. Whatever drives a collector, the system provides an intelligent means of setting priorities of value.

When you prepare for an evaluation, do your best to obtain accurate provenance. Exactly where did the artifact come from? When was it collected and by whom? Do any records back up the oral history? Look for information that may help explain what environments the artifact has been subjected to. If you collect modern pieces, you want to know who made it and even when it was made. Craftsmen who sign and date their work provide valuable information.

Keep your wits! The excitement of a rare find makes it difficult to be objective. Look at all your facts before you arrive at a decision. No system is foolproof, but you are much better off having a system. When you make an error in judgment, use the information to strengthen your abilities for the next time. It gets easier with practice.