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Intraoperative Invasive Blood Pressure Monitoring and the Potential Pitfalls

Intraoperative Invasive Blood Pressure Monitoring and the Potential Pitfalls

Descripción: Intraoperative Invasive Blood Pressure Monitoring and the Potential Pitfalls     Invasive intraarterial blood pressure measurement is currently the gold standard for intraoperative hemodynamic monitoring but accurate systolic blood pressure (SBP) measurement is difficult in everyday clinical practice, mostly because of problems with hyper-resonance or damping within the measurement system, which can lead to erroneous treatment decisions if these phenomena are not recognized. A hyper-resonant blood pressure trace significantly overestimates true systolic blood pressure while underestimating the diastolic pressure. Invasively measured systolic blood pressure is also significantly more affected than mean blood pressure by the site of measurement within the arterial system. Patients in the intraoperative period should be treated based on the invasively measured mean blood pressure rather than the systolic blood pressure. In this review, we discuss the pros/cons, mechanisms of Disposable IBP Transducers, and the interpretation of the invasively measured systolic blood pressure value.     Introduction & Background     Disposable IBP Transducer Kit-Single Channel is the gold standard of arterial pressure measurement in 10-20% of high-risk patients . In the remaining 80%-90% of surgical patients, the standard intermittent non-invasive blood pressure (BP) that is obtained using oscillometry with a brachial cuff has been shown to have only poor agreement with IBP in critically ill patients . These observed measurement differences are clinically significant because they would have triggered a change in treatment in as many as 20% of the critical care patients. Non-invasive oscillometric BP measurement with a brachial cuff tends to, on average, overestimate BP during hypotension and underestimate BP during hypertension, with a significant bias and considerable scatter. Invasive BP measurement with an arterial catheter, providing continuous BP measurements, detected nearly twice as many episodes of hypotension as intermittent oscillometric measurements with a brachial cuff . Continuous rather than intermittent hemodynamic monitoring is highly desirable in high-risk patients. Even when continuous BP monitoring was accomplished in medium-risk patients with non-invasive techniques, the number of episodes of intraoperative hypotension was still reduced by half when compared to intermittent monitoring with a brachial cuff . Although non-invasive continuous monitoring has fewer complications than arterial cannulation, it has not yet Disposable IBP Transducer Kit-Double Channel as the gold standard in high-risk patients, but rather serves as an alternative in low and medium-risk patients where IBP measurements are not warranted .     An adequate blood pressure level is a means to achieve the ultimate goal of the circulation, which is adequate end-organ perfusion and tissue oxygenation. Adequate organ perfusion is mostly regulated locally, in the organs, by changing the local vascular resistance, which, when seen over multiple organs and the entire circulation, works as a re-distribution of the total flow or cardiac output (CO) . In addition, the total flow or CO is also regulated centrally if this re-distribution is not enough. The local flow control via regulation of resistance of the arterioles only functions properly under the condition of adequate perfusion pressure, in which the mean systemic arterial pressure plays a central role. Continuous monitoring of local organ circulation, global flow, or CO and arterial pressure is, therefore, the key. Monitoring the microcirculation has been shown to be useful when determining the optimal BP range that is associated with adequate regulation of local blood flow and tissue oxygenation for an individual patient . Pulse contour analysis provides a means of assessing global flow or CO because it has long been recognized that an apparently adequate BP level may not necessarily be associated with an adequate total blood flow to all the tissues . Different organs have a different range of perfusion pressures that allow for adequate local control of organ flow. While the coronary circulation can increase flow fivefold as long as heart rate is maintained at 70 bpm, diastolic arterial pressure is maintained at adequate levels and coronary obstructive lesions are absent, the kidney is much more sensitive to decreases in perfusion pressure . The average lower limit of cerebral blood flow autoregulation in normotensive adult humans is around a mean arterial pressure (MAP) of 70 mmHg . Hence, the heart has a greater range of adequate perfusion pressures than both the brain and the kidneys. Blood pressure goals as adequate perfusion pressure ranges, therefore, need to be specifically determined and adjusted for every individual clinical situation by considering the patient’s specific comorbidities as well as the planned surgical procedure.     Blood pressure and surgical outcomes      Although the real target is adequate total blood flow and adequate local flow to individual organs, most outcome data are available for blood pressure. Hypotension has been associated with increased postoperative morbidity. Even short durations of intraoperative MAP less than 55 mmHg are associated with myocardial injury and acute kidney injury (AKI) . A perioperative quality initiative consensus statement also concluded that even brief durations of systolic arterial pressure

Fecha de Publicación: 27-01-22

Understanding Laser Cutting

Understanding Laser Cutting

Descripción: Understanding Laser Cutting     Laser cutting is a fabrication process which employs a focused, high-powered laser beam to cut material into custom shapes and designs. This process is suitable for a wide range of materials, including metal, plastic, wood, gemstone, glass, and paper, and can produce precise, intricate, and complex parts without the need for custom-designed tooling.     There are several different types of laser cutting available, including fusion cutting, oxidation cutting, and scribing. Each laser cutting process can produce parts with precision, accuracy, and high-quality edge finishes, and with generally less material contamination, physical damage, and waste than with other conventional cutting processes, such as mechanical cutting and waterjet cutting. However, while laser cutting demonstrates certain advantages over more conventional cutting processes, some manufacturing applications can be problematic, such as cutting reflective material or material requiring secondary machining and finishing work. The requirements and specifications demanded by a particular cutting application—e.g., materials and their properties, energy and power consumption limits, secondary finishing, etc.—help determine the type of cutting process most suitable for use.     While each cutting process has its advantages and disadvantages, this article focuses on laser cutting, outlining the basics of the laser cutting process and the necessary components and mechanics of the CNC laser cutting machine. Additionally, the article explores various laser cutting methods and applications, the benefits and limitations of the process, and comparisons between laser cutting and other types of cutting processes.       The Laser Cutting Machine and Process     Laser cutting is a non-contact, thermal-based fabrication process suitable for metal and non-metal materials. For the laser cutting process to run smoothly and at optimum capacity, several factors should be taken into consideration, such as the flatbed CNC laser cutting machine’s configuration and settings, the material being cut and its properties, and the type of laser and assist gas employed.     Stimulated Emission: The photons that are produced by spontaneous emission travel within the medium, which is contained in a cavity of the laser resonator between two mirrors. One mirror is reflective to keep photons traveling within the medium, so they continue to propagate stimulated emissions, and the other mirror is partially transmissive to allow some photons to escape. Stimulated emission is the process in which a photon (i.e., the incident photon) stimulates an atom that is already at a higher energy level. This interaction forces the stimulated atom to drop to its ground state by emitting a second photon of the same fixed wavelength or coherent with the incident photon.     The process of one photon propagating the emission of another photon amplifies the strength and intensity of the light beam. Thus the stimulated emission of light photons (i.e., a type of electromagnetic radiation) causes the amplification of light; in other words, light amplification by stimulated emission of radiation. Improperly aligned photons within the resonator pass through the partially transmissive mirror without being reflected into the medium, generating the initial laser beam. Once generated, the beam enters the laser cutting head and is directed by mirrors into the focusing lens.     Beam Focusing     The focusing lens focuses the laser beam through the center of the nozzle at the end of the laser cutting head incident to the workpiece’s surface. By focusing the beam, the lens concentrates the beam’s energy into a smaller spot, which increases the beam’s intensity (I).      Where P represents the power of the initial laser beam, and πr2 represents the cross-sectional area of the beam. As the lens focuses the laser beam, the radius (r) of the beam decreases; this decrease in radius reduces the cross-sectional area of the beam, which in turn increases its intensity since its power is now distributed across a smaller area.     Localized Heating and Melting, and Material Ejection      As the beam strikes the material’s surface, the material absorbs the radiation, increasing the internal energy and generating heat. The high intensity of the laser beam allows it to heat, melt, and partially or completely vaporize a localized area of the workpiece’s surface. The weakening and removal of the affected area of the material forms the desired cuts. Siphoned into the laser cutting head and flowing coaxially to the focused beam, the assist gas—also referred to as the cutting gas—is used to protect and cool the focusing lens, and may be used to expel melted material out of the kerf—the width of the material removed and of the cut produced—and support the cutting process. Laser cutting employs several different types of material cutting and removal mechanisms, including fusion cutting, chemical degradation cutting, evaporation cutting, scribing, and oxidation cutting.     Fusion Cutting: Also referred to as inert gas melt shearing or inert gas cutting, fusion cutting is employed by CO2 and Nd:YAG laser cutting machines. The laser beam produced by the cutting machine melts the workpiece, and melted material is expelled through the bottom of the kerf by a jet of the assist gas employed. The assist gas and the assist gas pressure employed are dependent on the type of material being cut, but the inert gas is always chosen based on its lack of chemical reactivity in regards to the material. This mechanism is suitable for laser cutting most metals and thermoplastics.     Chemical Degradation: Chemical degradation is employed by high end laser cutting machine and is suitable for laser cutting thermoset polymers and organic material, such as wood. As thermoset and organic materials do not melt when heat is applied, the laser beam burns the material instead, reducing it to carbon and smoke.     Evaporation Cutting: Evaporation cutting is employed by CO2 laser cutting machines and is suitable for materials such as laser cutting acrylic and polyacetal due to the closeness of their melting and boiling points. Since the laser evaporates material evaporates along the cut, the edge produced is generally glossy and polished.     Scribing: Scribing is employed by CO2 and Nd:YAG laser cutting machines to produce partial or fully penetrating grooves or perforations, usually on ceramics or silicon chips. These grooves and perforations allow for mechanical breaking along the weakened structural lines.     Oxidation Cutting: Also referred to as flame oxygen cutting, oxidation cutting is employed by CO2 and Nd:YAG laser cutting machines and is suitable for laser cutting of mild and carbon steel. Oxidation cutting is one example of the reactive gas melt shearing cutting mechanism, which specifically employs chemically reactive assist gases. As with inertness, the reactivity of an assist gas is relative to the material being cut. Oxidation cutting, as the name implies, employs oxygen as the assist gas, which exothermically reacts with the material. The heat generated accelerates the cutting process and produces an oxidized melted edge which can be easily removed by a gas jet to allow for a cleaner, laser-cut edge.     Beam Movement     Once the localized heating, melting, or vaporizing has started, the machine moves the area of material removal across the workpiece to produce the full cut. The machine achieves the movement either by adjusting the reflective mirrors, controlling the laser cutting head, or manipulating the workpiece. There are three different configurations for low power laser cutting machine, defined by the way in which the laser beam moves or is moved over the material: moving material, flying optics, and hybrid laser cutting systems.     Moving Material: Moving material laser cutting machines feature a stationary laser beam and a movable cutting surface to which the material is affixed. The workpiece is mechanically moved around the stationary beam to produce the necessary cuts. This configuration allows for a uniform and consistent standoff distance and requires fewer optical components.     Flying Optics: Flying optics laser cutting machines feature a movable laser cutter head and a stationary workpiece. The cutting head moves the beam across the stationary workpiece in the X- and Y-axes to produce the necessary cuts. The flexibility of flying optics machines is suitable for cutting materials with variable thickness and sizes, as well as allowing for faster processing times. However, since the beam is continually moving, the changing beam length has to be taken into consideration throughout the process. The changing beam length can be controlled by collimation (alignment of the optics), using a constant beam length axis, or employing an adaptive optics or capacitive height control system capable of making the necessary adjustments in real time.     Hybrid: Hybrid high power laser cutting machine offer a combination of the attributes found on moving material and flying optics machines. These machines feature a material handling table that moves on one axis (usually the X-axis) and a laser head that moves on another (usually the Y-axis). Hybrid systems allow for more consistent beam delivery, and reduced power loss and greater capacity per watt compared to flying optics systems.     Lasers are produced as either pulsed beams or continuous wave beams. The suitability of each depends on the properties of the material being cut and the requirements of the laser cutting applications. Pulsed beams are produced as short bursts of power output, while continuous wave beams are produced as continuous, high power output. The former is typically employed for scribing or evaporation cutting applications and is suitable for cutting delicate designs or piercing through thick materials, while the latter is suitable for high-efficiency and high-speed cutting applications.     Types of Assist Gases     Laser cutting employs a variety of assist gases to aid the cutting process. The cutting process employed and the material being cut determine the type of assist gas—either inert or active—that is most suitable for use.     Inert gas cutting (i.e., fusion cutting or inert gas melt shearing), as indicated by the name, employs chemically inert assist gases. The particular assist gas employed depends on the material’s reactive properties. For example, since molten thermoplastics do not react with nitrogen and oxygen, compressed air can be used as the assist gas when laser cutting such materials. On the other hand, since molten titanium does react with nitrogen and oxygen, argon—or another similarly chemically inert gas—must be used as the assist gas in laser cutting applications involving this material. When laser cutting stainless steel via the inert gas cutting process, nitrogen is typically used as the assist gas; this is because molten stainless steel chemically reacts with oxygen.     When laser cutting material via the reactive melt shearing process, an active (i.e., chemically reactive) assist gas—typically oxygen—is employed to accelerate the cutting process. While in inert gas cutting the material is heated, melted, and vaporized solely by the power of the laser, in reactive gas cutting the reaction between the assist gas and the material creates additional heat which aids the cutting process. Because of this exothermic reaction, reactive gas cutting typically requires lower laser power levels to cut through a material compared to the power level necessary when cutting the same material via the inert gas cutting process.     The cutting pressure of the assist gas employed is also determined by the cutting process employed and the properties and thickness of the material being cut. For example, polymers typically require gas jet pressures of 2–6 bar during the inert gas cutting process, while stainless steel requires gas jet pressures of 8–14 bar. Accordingly, thinner materials also generally require lower pressures, and thicker materials generally require greater pressures. In oxidation cutting, the opposite is true: the thicker the material, the lower the pressure required and the thinner the material, the higher the pressure required.     Types of Laser Cutting Machines     There are several types of laser cutting machines available which are categorized into gas, liquid, and solid state lasers. The types are differentiated based on the state of the active laser medium—i.e., whether the medium is a gas, liquid, or solid material—and what the active laser medium consists of (e.g., CO2, Nd:YAG, etc.). The main two types of lasers employed are CO2 and solid-state lasers.     One of the most commonly employed gas state lasers, a CO2 laser employs a carbon dioxide mixture as the active laser medium. CO2 lasers are typically used to cut non-metal materials since early models were not powerful enough to cut through metals. Laser technology has since evolved to enable CO2 lasers to cut through metals, but CO2 lasers are still better suited for cutting through non-metals and organic materials (such as rubber, leather, or wood) and simply engraving metals or other hard materials. Pure nitrogen lasers are another commonly used gas state laser. These lasers are used for applications that require the material not oxidize as it is cut.     There are several varieties of solid-state lasers available, including crystal and fiber lasers. Crystal lasers employ a variety of crystal mediums—e.g., neodymium-doped yttrium aluminum garnet (Nd:YAG) or neodymium-doped yttrium orthovanadate (Nd:YVO4)—which allow for high-powered metal and non-metal laser cutting. Although versatile in regards to their material cutting capabilities, crystal lasers are typically more expensive and have shorter lifespans than other types of lasers. Fiber lasers offer a cheaper and longer lasting alternative to crystal lasers. This type of laser first generates a beam through a series of laser diodes which is then transmitted through optical fibers, amplified, and focused on the workpiece to perform the necessary cuts.     Laser Cutting Machine Considerations     As described in the previous section, the type of laser suitable for a laser cutting application is largely determined by the material being cut. However, other considerations may be taken into account when choosing and setting up a laser cutting machine for a specific application, such as the machine configuration, laser power, wavelength, temporal mode, spatial mode, and focal spot size.

Fecha de Publicación: 27-01-22

The playing card factory

The playing card factory

Descripción: The playing card factory     Our long, rich history began when A. O. Russell, Robert J. Morgan, James M. Armstrong and John F. Robinson Jr. formed a partnership and purchased from the proprietors of The Cincinnati Enquirer what was then known as the Enquirer Job Printing Rooms. The spaces occupied the first and second stories of the building at 20 College Street in Cincinnati, Ohio. The firm commenced business as Russell, Morgan & Co., referring to the two printers in the partnership.     While on College Street, the firm printed theatrical and circus posters, placards and labels. By 1872, the business had increased so much, it was forced to seek larger quarters, and in November 1872, it moved into a new, four-story building on nearby Race Street in downtown Cincinnati.     Mr. Russell proposed to his partners that they embark upon the manufacture of playing cards, an industry monopolized by several East Coast companies. The partners agreed and arrangements were made to add two additional stories to their building, making it six stories high. Many new machines were designed and built expressly for Russell, Morgan & Co. The first deck of playing cards was completed on June 28, 1881. About 20 employees manufactured 1600 packs per day.     IN 1891     Russell, Morgan & Co. became The United States Printing Company. Only three years later (1894), the playing card business had grown to such proportions that it was separated from the Printing Company, becoming The United States Playing Card Company.     The United States Playing Card Company gained immediate advantages, for it acquired other notable companies: The Standard Playing Card Co (Chicago), Perfection Card Co (New York) and New York Consolidated Cards Company. New York Consolidated Card Company had antecedents dating back to 1833 when Lewis I. Cohen perfected his four-color press for printing playing cards. The famous "Bee"? Playing Cards still issued by The United States Playing Card Company, had originated at the New York Consolidated Card Company in 1892.     Congress? playing cards is one of the original brands from 1881 which is still in production today and the card of choice for sophisticated bridge players. Likewise, the world-renowned Bicycle? playing card brand has been in continuous production since 1885.     THE JOKER     The Joker is an American invention dating from about 1865 and has made different appearances in the Bicycle? card line. The first type represented a man on a high-wheeled bike. The bicycle later acquired two wheels of normal size. Then followed a series of playing card kings on bikes. These cyclists wheel past a milestone marked "808." Contrary to some opinions, this number has no mystical meaning. It is merely a reference number distinguishing this brand from others (such as "606") by the same company.     STATUE OF FREEDOM     The Ace of Spades carries another code, identifying the year in which the deck was printed. This Ace features, within the suit sign, a woman who rests her right hand on a sword and shield while she holds an olive branch in her left. The image was inspired by Thomas Crawford's sculpture, "Statue of Freedom." which, in 1865, had been placed atop the Capitol Building in Washington, DC.     BY 1900     The United States Playing Card Company expanded again, moving from downtown Cincinnati to a newly built factory in Norwood. Situated on over 30 acres, the facility would eventually accommodate over 600,000 square feet of manufacturing operations.     BELL TOWER     A Neo-Romanesque bell tower (4-stories high) was built in 1926 atop the company's 4-story main building entrance. This tower housed a fine set of 12 carillon bells, ranging in size from 1-1/2 to 5-1/2 feet. This was the first set of chimes built for radio broadcasting. The chimes were connected electronically to radio station WSAI, which was owned and operated by The United States Playing Card Company from 1922 until 1930 and located within The United States Playing Card Companycomplex. The main reason for the radio station was to promote the game of bridge by broadcasting bridge lessons. In those days, there was no limitation on the range of radio power and the WSAI transmission was so clear and strong that it could be picked up as far away as New Zealand. WSAI was eventually sold in the 1930's to the Crosley Radio Corporation.     During World War II, the company secretly worked with the U. S. government in fabricating special decks to send as gifts for American prisoners of war in German camps. When these cards were moistened, they peeled apart to reveal sections of a map indicating precise escape routes. Also during the war, The United States Playing Card Companyprovided "spotter" cards, which illustrated the characteristic shapes of tanks, ships and aircraft from the more powerful countries. The company further assisted by sewing parachutes for anti-personnel fragmentation bombs.     ACE OF SPADES     The Ace of Spades served a famous purpose in the war in Vietnam. In February, 1966, two lieutenants of Company "C," Second Battalion, 35th Regiment, 25th Infantry Division, wrote The United States Playing Card Company and requested decks containing nothing but the Bicycle? Ace of Spades. The cards were useful in psychological warfare. The Viet Cong were very superstitious and highly frightened by this Ace. The French previously had occupied Indo-China, and in French fortunetelling with cards, the Spades predicted death and suffering. The Viet Cong even regarded lady liberty as a goddess of death. USPC shipped thousands of the requested decks gratis to our troops in Vietnam. These decks were housed in plain white tuck cases, inscribed "Bicycle? Secret Weapon." The cards were deliberately scattered in the jungle and in hostile villages during raids. The very sight of the Bicycle? Ace card was said to cause many Viet Cong to flee.     The company acquired Heraclio Fournier, S.A., the poker playing cards manufacturer in Europe. In 1987, The United States Playing Card Company acquired Arrco Playing Card Company, the third largest playing card manufacturer in the country. International Playing Card Company, a Canadian subsidiary of The United States Playing Card Company since 1914, maintained its own manufacturing operation from 1928 to 1991. Currently, International Playing Card Company is a sales and marketing organization located in Ontario. The United States Playing Card Company was acquired by a series of new owners: Diamond International in 1969, Jessup & Lamont in 1982, Frontenac in 1989.     Playing cards were invented in Ancient China. They were found in China as early as the 9th Century during the Tang Dynasty (618–907). The first reference to the card game in world history dates no later than the 9th Century, when the Collection of Miscellanea at Duyang, written by Tang Dynasty writer Su E, described Princess Tongchang (daughter of Emperor Yizong of Tang) playing the “leaf game” in 868 with members of the Wei clan (the family of the princess’ husband). The Song Dynasty (960–1279) scholar Ouyang Xiu (1007–1072) asserted that playing cards and card games existed at least since the mid-Tang Dynasty and associated their invention with the simultaneous development of using sheets or pages instead of paper rolls as a writing medium. The first known book on cards called Yezi Gexi was allegedly written by a Tang-era woman, and was commented on by Chinese writers of subsequent dynasties.     During the Ming Dynasty (1368-1644), characters from popular novels such as the Water Margin were widely featured on the faces of playing cards. By the 11th century playing cards could be found throughout the Asian continent.     Ancient Chinese “money cards” have four “suits”: coins (or cash), strings of coins (which may have been misinterpreted as sticks from crude drawings), myriads (of coins or of strings), and tens of myriads (where a myriad is 10,000). These were represented by ideograms, with numerals of 2–9 in the first three suits and numerals 1–9 in the “tens of myriads”. Wilkinson suggests that the first cards may have been actual paper currency which were both the tools of gaming and the stakes being played for, as in trading card games. The designs on modern Mahjong tiles likely evolved from those earliest playing cards. However, it may be that the first deck of cards ever printed was a Chinese domino deck, in whose cards we can see all the 21 combinations of a pair of dice. In Kuei-t’ien-lu, a Chinese text redacted in the 11th Century, we find that dominoes cards were printed during the Tang Dynasty, contemporary to the first printed books. The Chinese word pái (牌) is used to describe both paper cards and gaming tiles.     Introduction into Europe     Playing cards first entered Europe in the late 14th Century, probably from Mamluk Egypt, with suits very similar to the tarot suits of Swords, Staves, Cups and Coins (also known as Disks, and Pentacles) and those still used in traditional Italian, Spanish and Portuguese decks. The first documentary evidence is a ban on their use in 1367, Bern, Switzerland. Wide use of foil playing cards in Europe can, with some certainty, be traced from 1377 onwards.     The Mameluke deck contained 52 cards comprising four “suits”: polo sticks, coins, swords, and cups. Each suit contained ten “spot” cards (cards identified by the number of suit symbols or “pips” they show) and three “court” cards named malik (King), nā’ib malik (Viceroy or Deputy King), and thānī nā’ib (Second or Under-Deputy). The Mameluke court cards showed abstract designs not depicting persons (at least not in any surviving specimens) though they did bear the names of military officers.     A complete pack of Mameluke playing cards was discovered by Leo Mayer in the Topkap? Palace, Istanbul in 1939. This particular complete pack was not made before 1400, but the complete deck allowed matching to a private fragment dated to the 12th or 13th Century. In effect it is not a complete deck, but there are cards of three packs of the same style.     Various Ganjifa cards from Dashavatara set, with ten suits depicting the ten Avatars of the god Vishnu.     It is not known whether these cards influenced the design of the Indian cards used for the game of Ganjifa, or whether the Indian cards may have influenced these. Regardless, the Indian cards have many distinctive features: they are round, generally hand painted with intricate designs, and comprise more than four suits (often as many as thirty two, like a deck in the Deutsches Spielkarten-Museum, painted in the Mewar, a city in Rajasthan, between the 18th and 19th Century. Decks used to play have from eight up to twenty suits).     Spread across Europe and early design changes     Italian playing cards, Sancai-type bowl, Northern Italy, mid-15th Century.     In the late 14th Century, the use of playing cards spread rapidly throughout Europe. Documents mentioning cards date from 1371 in Spain, 1377 in Switzerland, and 1380 in many locations including Florence and Paris. A 1369 Paris ordinance does not mention cards, but its 1377 update does. In the account books of Johanna, Duchess of Brabant and Wenceslaus I, Duke of Luxemburg, an entry dated May 14, 1379, reads: “Given to Monsieur and Madame four peters, two forms, value eight and a half moutons, wherewith to buy a pack of cards”. In his book of accounts for 1392 or 1393, Charles or Charbot Poupart, treasurer of the household of Charles VI of France, records payment for the painting of three sets of cards.     The earliest cards were made by hand, like those designed for Charles VI; this was expensive. Printed woodcut decks appeared in the 15th Century. The technique of printing woodcuts to decorate fabric was transferred to printing on paper around 1400 in Christian Europe, very shortly after the first recorded manufacture of paper there, while in Islamic Spain it was much older. The earliest dated European woodcut is 1418. No examples of printed cards from before 1423 survive. But from about 1418 to 1450 professional card makers in Ulm, Nuremberg, and Augsburg created printed decks. Playing cards even competed with devotional images as the most common uses for woodcut in this period.     Most early woodcuts of all types were coloured after printing, either by hand or, from about 1450 onwards, stencils. These 15th Century playing cards were probably painted.     The Master of the barcode playing cards worked in Germany from the 1430s with the newly invented printmaking technique of engraving. Several other important engravers also made cards, including Master ES and Martin Schongauer. Engraving was much more expensive than woodcut, and engraved cards must have been relatively unusual.     In the 15th Century in Europe, the suits of advertising playing cards varied; typically a deck had four suits, although five suits were common and other structures are also known. In Germany, hearts (Herz/Rot), bells (Schellen), leaves (Grün), and acorns (Eichel) became the standard suits and are still used in Eastern and Southeastern German decks today for Skat, Schafkopf, Doppelkopf, and other games. Italian and Spanish cards of the 15th century used swords, batons (or wands), cups, and coins (or rings). The Tarot, which included extra trump cards, was invented in Italy in the 15th century.     The four suits now used in most of the world — Spades, Hearts, Diamonds, and Clubs — originated in France in approximately 1480. The trèfle (club) was probably copied from the acorn and the pique (spade) from the leaf of the German suits. The names “pique” and “spade”, however, may have derived from the sword of the Italian suits. In England, the French suits were eventually used, although the earliest decks had the Italian suits.     Also in the 15th Century, Europeans changed the court cards to represent European royalty and attendants, originally “king”, “chevalier” (knight), and “knave”. The original meaning of knave was male child, so in this context the character could represent the “prince”, son to the King and Queen; the meaning servant developed later. In a German pack from the 1440s, Queens replace Kings in two of the suits as the highest card. Fifty-six-card decks containing a King, Queen, Knight, and Valet (from the French tarot court) were common.     Court cards designed in the 16th Century in the manufacturing centre of Rouen became the standard design in England, while a Parisian design became standard in France. Both the Parisian and Rouennais court cards were named after historical and mythological heroes and heroines. The Parisian names have become more common in modern use, even with cards of Rouennais design.

Fecha de Publicación: 27-01-22

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