Wednesday, March 16, 2016

Discovering Glass: Hollow Glass Beads

Long metallic hollow beads and
pastel color hollow glass pearls.
In center a salesman sample card
with hollow pearls and dyed
hollow beads imitating coral, jade,
jet or onyx and turquoise.
Hollow glass beads are beads that are blown from glass tube and formed into shape by hand or a mold. Smaller beads are blown from a hot glass tube that is in a mold. Hot glass takes the shape of the mold and a rows of beads are created. After inserting a color or silver into the tube, the beads are separated by cutting. These are usually dyed from inside but sometimes are colored on the surface. Dye on the surface is very likely to be worn off. Surface of the glass can also be given a matte treatment that gives the beads a frosted look. Transparent topaz, opaque black, satin/atlas glass and other kind of glass was also used when making hollow glass beads.

Most of the hollow glass beads are the ones that have shiny silver lining. These metallic hollow glass beads are sometimes called mercury beads because there was mercury used in the beginning of the production. It was soon replaced and the receipt of the formula has changed over the time. Also real gold was used in the early days. Metallic hollow glass beads are still in production and are widely used for example making decorations for Christmas.

Metallic hollow glass beads dyed in pink.
Bigger flat beads have frosted finish.
Small beads measure 2-2,5mm.
Earlier glass pearls were also made of hollow glass tubes and dyed with essence d'orient (a liquid formula with fish scale powder). Hollow glass pearls were mostly formed by hand one at the time. Handmade pearls have different sized holes (the bigger one was where glass blower inserted the air) and of course the size and shape vary. Small pearls were made in a row and these have similar shaped holes that have a "neck" with cut edge (like the metallic hollow glass beads are made today). Hollow glass pearls in jewelry were replaced by solid glass beads covered with pearl-coating as chemical industry made its progress. And while hollow pearls were still in use in garment embroidery up to 1940s the revolution of plastic superseded with its lower price, durability and bigger array of colors.

When there was a search of cheaper alternatives for natural materials such as coral, turquoise, jade,  jet etc. the demand for dyed hollow glass beads boosted. Hollow glass beads were created the same way but dyed in different colors to resemble natural products. When business with colorful glass canes became more active then there was no need to dye colorless glass anymore. To get bright coral red the bead makers used white opaque glass as the core and added thin layer of transparent red to the surface.
Tiara with hollow red coral glass beads.
Photo from Creative Museum

Õõnsad klaashelmed on helmed, mida valmistatakse klaastuubist puhumise teel ning millele antakse helme kuju kas käsitsi või vormiga. Väiksemate helmeste puhul puhutakse klaastuub vormi sees nii, et puhudes kuum klaas võtab vormi kuju. Valminud helmeste rida värvitakse seest poolt ning lõigatakse lahti. Tavaliselt värvitakse need seest poolt, kuid on ka helmeid, millel värvikiht on väljas pool. Helme peal olev värvikiht aga kulub kergelt. Klaasipinda võib olla ka töödeldud matiks, mis annab helmestele jäätunud ilme. Läbipaistev topaas, läbipaistmatu must, "satin" klaas ja ka teisi klaase on samuti kasutatud õõnsate helmeste valmistamisel.

Metallic hollow glass beads in
various shapes and colors.
Enamik õõnsaid helmeid on seest hõbetatud. Metallivärvi õõnsad klaashelmed kannavad vahest ka nime "mercury beads", sest alguses kasutati metalses kihis elavhõbedat. See muidugi asendati kiirelt ning aegade jooksul on metalse värvi retsepti muudetud mitmeid kordi. Samuti oli alguses kasutusel ka päris kuld, millega kullati klaashelmeid seest või väljast. Metallivärvi õõnsaid klaashelmeid tootetakse ka tänapäeval ja kasutatakse (nt. jõulu-) dekoratsioonide valmistamisel.

Antique hollow glass pearls in various shapes and sizes.
Many of them have flat side so they stay in place when embroidered.
Varasemad imitatsioonpärlid olid samuti valmistatud õõnsast klaasist. Õõnsad klaaspärlid valmistati samuti klaastuubist ning värviti seestpoolt kalasoomustest valmistatud vedelikuga, mida nimetati "essence d'orient". Õnnsad klaaspärlid valmistati enamasti ükshaaval ja käsitsi. Käsitsi valmistatud klaaspärlitel on helme augud erineva suurusega (suuremasse puhus klaasimeister õhku) ning loomulikult olid pärlite suurus ja kuju varieeruvad (kuigi kasutati erinevaid tange vormimisel). Väikseid pärleid valmistati samuti ühe pika reana, mis pärast seest värvimist üksteise küljast lahti lõigati (nagu metalseid helmeid tänapäevalgi). Nendel pärlitel on mõlemad augud enamvähem samasugused ning augul on nn "kael", kus helmes teise küljest lahti lõigati. Ehete valmistamises asendati õõnsad klaaspärlid (täis)klaasist pärlitega (klaashelmes, mille peal on pärlmutrise värvikiht) siis, kui keemiatööstuse arenedes suudeti luua piisavalt kulumiskindel pärlmutrine värv. Ja kuigi õõnsaid klaapärleid on näha rõivastel kuni 1940ndateni, siis plastmassi-revolutsiooniga asendati need odavama, vastupidavama ja värviküllasema plastiku valikuga.

Lace gown (1915) with orange
coral colored
hollow beads
in round and tube shape.
Photo from smugmug.com
Kui otsiti odavamaid alternatiive ka teistele looduslikele materjalidele nagu türkiis, korall, jadeiit, jet jms. siis tekkis nõudlus värvitud õõnsate klaashelmeste järele. Värvitud õõnsad klaashelmed valmistati samamoodi kui õõnsad klaaspärlid, lihtsalt seest värviti need vastavalt seda värvi, millist materjali taheti imiteerida. Kaubanduse edenedes said paljud helmeste valmistajad enda valdusse suurema valiku värvilist klaasi ning läbipaistva klaasi seespidine värvimine polnud enam vajalik. Et saada korallpunast, tegi helme valmistaja läbipaistmatust valgest klaasist helme südamiku ning kandis selle peale õhukese kihi punast läbipaistvat klaasi.