{"version":3,"file":"LashScienceData.BC7888Ul.mjs","names":[],"sources":["https:/framerusercontent.com/modules/dNTioZFe165jgrS2dGp1/AmEfQH3jcStGM4DFCXhX/LashScienceData.js"],"sourcesContent":["// Lash science series: the shapes every chapter is written in, the list of chapters, and the first finished chapter\n// (the physics of a lash). Brief, decisions and source checks: outputs/beautiatelier/lash-science/README.md.\n// Every factual line carries the number of its source in that chapter's own list. Lines about the atelier's own practice\n// need Brynne's sign-off before the series is made public. No long dashes in copy.\nexport const SERIES={path:\"/lash-science\",name:\"Lash science\",hub:{crumb:\"Beautiatelier\",title:\"Lash science\",lead:\"Twelve chapters on the eyelash and on the craft built around it: what a lash is, why it is shaped the way it is, and what an extension asks of it. Every fact is tied to its source.\",note:\"Written at the atelier, checked against the published research. Where something is still a hypothesis, the text says so.\",metaTitle:\"Lash Science: 12 Chapters on Lashes | Beautiatelier\",metaDescription:\"Twelve sourced chapters on the eyelash and on extensions: anatomy, chemistry, physics, evolution, history, fibres, adhesive, method and design.\"},here:\"This chapter\",soon:\"In preparation\",read:\"Read\",next:\"Next chapter\",prev:\"Previous chapter\",all:\"All chapters\",volumes:[{name:\"The natural lash\",line:\"What a lash is, how it grows, what it does, and how to keep it.\",keys:[\"anatomy\",\"chemistry\",\"physics\",\"evolution\",\"psychology\",\"health\"]},{name:\"Extensions\",line:\"Where the craft came from, what it is made of, and how it is done well.\",keys:[\"history\",\"purpose\",\"fibres\",\"adhesive\",\"application\",\"art\"]}],list:{anatomy:{nav:\"Anatomy and the growth cycle\",line:\"The follicle, the glands beside it, and the months-long life of a single lash.\"},chemistry:{nav:\"Chemistry: keratin, bonds, pigment\",line:\"What a lash is made of, and what a lash lift does to it.\"},physics:{nav:\"Physics: length, curve, structure, load\",line:\"Why a lash is as long as it is, why it curves, and how much it can carry.\"},evolution:{nav:\"Evolution and function\",line:\"Which animals have lashes, and what they are for.\"},psychology:{nav:\"Psychology and the perception of beauty\",line:\"What lashes change in how a face is read, measured.\"},health:{nav:\"Health: keeping and improving natural lashes\",line:\"What the evidence says about care, loss, serums and recovery.\"},history:{nav:\"Origin and history\",line:\"From kohl to the first patents to the one-to-one extension.\"},purpose:{nav:\"Purpose and psychology\",line:\"Why people wear extensions, and what they report afterwards.\"},fibres:{nav:\"Fibres: materials and their physics\",line:\"What an extension is made of, and why diameter decides almost everything.\"},adhesive:{nav:\"Adhesive: the bond and the eye\",line:\"How lash glue cures, what it breaks down into, and what clinics and regulators have found.\"},application:{nav:\"Application: method, mechanics and retention\",line:\"Isolation, the gap from the lid, stuck lashes, and the arithmetic of a fill.\"},art:{nav:\"The art: mapping, styles and textures\",line:\"What a dark lash line does to an eye, measured, and the craft vocabulary, kept apart.\"}}};export const PHYSICS={key:\"physics\",crumb:\"Lash science \\xb7 The natural lash\",title:\"The physics of a lash\",lead:\"Every lash is a small piece of engineering. Its length manages the air in front of your eye, its curve throws off water, and its thickness decides how much it can carry. Those three facts set the rules for every set we apply.\",hero:{kind:\"lashrow\"},metaTitle:\"The Physics of an Eyelash | Beautiatelier\",metaDescription:\"How long a lash should be, why it curves and how much it can carry: the physics of the natural lash, with the studies behind each number.\",interlude:{after:\"length\",kind:\"air\",line:\"A pocket of still air, held in place by a row of hairs.\",sub:\"It is in front of your eye now.\"},secs:[{id:\"length\",cap:\"Length\",title:\"One third of the eye\",layout:\"top\",p:[{t:\"In 2015 a team at Georgia Tech measured the lashes of 22 species of mammals. On average, the lashes were about one third as long as the eye is wide.\",s:1},{t:\"They then put a model eye in a wind tunnel. At that length, lashes halved the evaporation of the tear film and the dust reaching the eye. Shorter lashes shelter less. Longer lashes do something worse: they act as a funnel and carry the air down onto the eye.\",s:1}],fig:{kind:\"flow\",cap:\"Air meeting the eye head-on, seen in cross-section. A drawing of the mechanism the study describes, not its data.\",slider:\"Lash length, as a share of the eye's width\",ticks:[\"No lashes\",\"One third\",\"Longer\"],chart:\"Evaporation and dust reaching the eye\",states:[\"Too short to shelter the eye. The air reaches the surface.\",\"Sheltered. A pocket of still air sits over the eye: about half the evaporation, about half the dust.\",\"Too long. The lashes funnel air down onto the eye.\"]},atelier:\"We measure the width of your eye before we choose a length. The longest fibres go where your eye can carry them, and the set as a whole stays close to its natural proportion. For more drama we change the curl, the density and the map before we add length.\",link:{label:\"Length, in the library\",href:\"/library/application#length\"}},{id:\"curve\",cap:\"Curve\",title:\"Built to throw off water\",tone:\"stone\",p:[{t:\"A lash repels water, and its surface is covered in scales that overlap like roof shingles, all pointing to the tip. Water travels easily from root to tip and hardly at all the other way.\",s:2},{t:\"The curve does the rest. In 2024 researchers at the Chinese Academy of Sciences found that a lash bends close to the brachistochrone, the curve down which a drop falls fastest.\",s:2},{t:\"In their tests, a curved, flexible, water-repellent row of lashes cut the time water stays in contact by about a fifth compared with straight, rigid slopes.\",s:2}],fig:[{kind:\"race\",cap:\"Two drops released together, one on the curve of a lash and one on a straight line between the same points.\",again:\"Run it again\",first:\"Arrives first\",later:\"Arrives later\",root:\"Root\",tip:\"Tip\"},{kind:\"scales\",cap:\"The surface of a lash, enlarged: scales overlap toward the tip, so water moves one way.\",root:\"Root\",tip:\"Tip\"}],atelier:\"An extension continues the lash's own line. We choose the curl from the angle your natural lash already grows at, so the base of the fibre lies flat along it and the bond holds.\",link:{label:\"Curl, in the library\",href:\"/library/application#curl\"}},{id:\"structure\",cap:\"Structure\",title:\"What a lash is made of\",layout:\"rev\",p:[{t:\"Under a microscope, a lash is three parts that fit inside one another.\",s:3}],fig:{kind:\"parts\",art:\"cross\",cap:\"A lash cut across. Choose a layer.\",label:\"A lash cut across: a core of loose cells, a thick middle that holds the pigment, and an outer layer of flat sealed cells\",parts:[{key:\"cuticle\",name:\"Cuticle\",line:\"Several layers of flat cells, sealed tight. It keeps water out and protects what is inside.\"},{key:\"cortex\",name:\"Cortex\",line:\"The thick middle. It gives the lash its strength, and it holds the melanin that gives it colour.\"},{key:\"medulla\",name:\"Medulla\",line:\"A core of loose cells at the centre.\"}]},facts:[[\"90 to 160\",\"lashes on the upper lid, in five or six rows\"],[\"75 to 80\",\"lashes on the lower lid, in three or four rows\"],[\"0.12 to 0.14 mm\",\"of growth a day\"],[\"4 to 10 weeks\",\"of growth, in a life of 4 to 11 months\"],[\"12 mm\",\"the length a lash rarely passes\"],[\"No muscle\",\"a lash cannot move itself, unlike the hair on your arm\"]],factsSource:3,after:[{t:\"Lashes also differ from person to person. In a study of 4,661 lashes, thickness, number and the angle of lift all varied between groups of women. Length and growth rate did not.\",s:4}],atelier:\"Every lash is on its own clock, so a set sheds a few fibres a day with the lashes that carry them. That is the reason for a fill every two to three weeks, and the reason we never bond two lashes together.\",link:{label:\"Retention and fills, in the library\",href:\"/library/application#retention\"}},{id:\"load\",cap:\"Load\",title:\"Thickness and length both set the load\",tone:\"stone\",p:[{t:\"A lash is a beam fixed at one end, and an extension is a weight added along it. Two rules from first-year mechanics decide the rest.\",s:6},{t:\"The weight of a fibre grows with the square of its diameter. Double the diameter and it weighs four times as much. Add two millimetres to a ten millimetre fibre and it weighs a fifth more. Length costs twice: the fibre is heavier, and that weight sits farther from the root.\",s:6},{t:\"The stiffness of the natural lash grows with the fourth power of its diameter. A lash twice as thick is sixteen times harder to bend, which is why a fine lash and a strong lash cannot carry the same set.\",s:6}],fig:{kind:\"load\",pick:\"Choose a fibre diameter\",one:\"One classic fibre, 0.15 mm\",cap:\"Fibres of the same length and material. Real fibres taper to a point, so each weighs less than a plain cylinder, and the ratios stay close.\"},atelier:\"This is the arithmetic behind volume work. A hand-made fan of four 0.07 mm fibres is lighter than one 0.15 mm classic fibre, and it covers far more of the lash line. We choose the diameter from the lash that has to carry it.\",link:{label:\"Thickness and weight, in the library\",href:\"/library/application#thickness\"}},{id:\"beauty\",cap:\"Beauty\",title:\"Beauty follows the same number\",layout:\"rev\",p:[{t:\"In 2023 two psychologists showed people faces whose lashes ran from none at all to half the width of the eye, and asked how attractive each one was.\",s:5},{t:\"The answer rose and then fell. It peaked close to one third of the eye's width: about a quarter for some faces, up to two fifths for others.\",s:5},{t:\"The length people prefer and the length that shelters the eye best are in the same range. The authors suggest we read that proportion as a sign of health. That part is a hypothesis. The preference is the measurement.\",s:5}],fig:{kind:\"curve\",label:\"Attractiveness ratings rise with lash length, peak near one third of the eye's width and fall again\",series:[{pts:[[0,.03],[.1,.08],[.2,.2],[.3,.42],[.4,.68],[.5,.88],[.6,.99],[.66,1],[.74,.95],[.84,.8],[.92,.66],[1,.52]]}],x:[\"No lashes\",\"Half the eye's width\"],y:\"Rated more attractive\",band:{from:.5,to:.8,label:\"Most preferred\"},mark:{x:.667,label:\"Best sheltered: one third\"},cap:\"The shape of the result, redrawn. The faces were computer generated and rated online.\"}}],atelier:{title:\"Three measurements before any set\",rows:[[\"Length\",\"from the width of your eye\"],[\"Curl\",\"from the angle of your own lash\"],[\"Weight\",\"from the lash that has to carry it\"]],p:\"A free 30-minute consultation comes first. We look at your natural lashes under magnification and draw the map before a single fibre is placed.\"},sources:[{n:1,authors:\"Amador, Mao, DeMercurio, Montero, Clewis, Alexeev and Hu\",title:\"Eyelashes divert airflow to protect the eye\",where:\"Journal of the Royal Society Interface, 2015\",href:\"https://doi.org/10.1098/rsif.2014.1294\",grade:\"Measured: 22 species and a wind tunnel\"},{n:2,authors:\"Zhou, Chen, Cheng, Gao, He, Wang, Jiang, Dai and Dong\",title:\"Rapid water drainage on human eyelashes of a hydrophobic Brachistochrone fiber array\",where:\"Science Advances, 2024\",href:\"https://doi.org/10.1126/sciadv.adr2135\",grade:\"Measured in the laboratory\"},{n:3,authors:\"Aumond and Bitton\",title:\"The eyelash follicle features and anomalies: a review\",where:\"Journal of Optometry, 2018\",href:\"https://doi.org/10.1016/j.optom.2018.05.003\",grade:\"Review of the published research\"},{n:4,authors:\"Na, Kwon, Kim, Park, Oh, Kim, Cho and Eun\",title:\"Ethnic characteristics of eyelashes: a comparative analysis in Asian and Caucasian females\",where:\"British Journal of Dermatology, 2006\",href:\"https://doi.org/10.1111/j.1365-2133.2006.07495.x\",grade:\"Measured: 4,661 lashes on 30 women\"},{n:5,authors:\"Pazhoohi and Kingstone\",title:\"Eyelash length attractiveness across ethnicities\",where:\"Scientific Reports, 2023\",href:\"https://doi.org/10.1038/s41598-023-41739-5\",grade:\"One study: computer-generated faces, rated online\"},{n:6,authors:\"Textbook mechanics\",title:\"The weight of a round fibre, the stiffness of a round beam, and the curve of fastest descent\",where:\"Our own arithmetic, shown in the text\",grade:\"Standard physics, applied by us\"}]};\nexport const __FramerMetadata__ = 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