Category Science

HOW IS FILM DEVELOPED?

After an image has been recorded on light-sensitive film in a camera, the film is moved along, so that the next photograph will be taken on a fresh piece of film. No more light must hit the exposed film until it is developed, or the picture would be spoiled. When all the photographs on a roll of film have been taken, the film is wound into its case, which is lightproof. The development process then takes place in a darkroom, or in a specially made machine.

Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.

All processes based upon the gelatin-silver process are similar, regardless of the film or paper’s manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films. Kodachrome required Kodak’s proprietary K-14 process. Kodachrome film production ceased in 2009, and K-14 processing is no longer available as of December 30, 2010. llfochrome materials use the dye destruction process.

All photographic processing use a series of chemical baths. Processing, especially the development stages, requires very close control of temperature, agitation and time.

  1. The film may be soaked in water to swell the gelatin layer, facilitating the action of the subsequent chemical treatments.
  2. The developer converts the latent image to macroscopic particles of metallic silver.
  3. A stop bath, typically a dilute solution of acetic acid or citric acid, halts the action of the developer. A rinse with clean water may be substituted.
  4. The fixer makes the image permanent and light-resistant by dissolving remaining silver halide. A common fixer is hypo, specifically ammonium thiosulfate.
  5. Washing in clean water removes any remaining fixer. Residual fixer can corrode the silver image, leading to discolouration, staining and fading.

The washing time can be reduced and the fixer more completely removed if a hypo clearing agent is used after the fixer.

  1. Film may be rinsed in a dilute solution of a non-ionic wetting agent to assist uniform drying, which eliminates drying marks caused by hard water. (In very hard water areas, a pre-rinse in distilled water may be required – otherwise the final rinse wetting agent can cause residual ionic calcium on the film to drop out of solution, causing spotting on the negative.)
  2. Film is then dried in a dust-free environment, cut and placed into protective sleeves.

Once the film is processed, it is then referred to as a negative. The negative may now be printed; the negative is placed in an enlarger and projected onto a sheet of photographic paper. Many different techniques can be used during the enlargement process. Two examples of enlargement techniques are dodging and burning. Alternatively (or as well), the negative may be scanned for digital printing or web viewing after adjustment, retouching, and/or manipulation.

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HOW DOES A CAMERA WORK?

A camera is a lightproof box containing light-sensitive film. To take a picture, the photographer presses a button to open a shutter and let light pass through the aperture, a hole in the front of the camera. The camera’s lens focuses the light so that it forms a sharp image on the photographic film, just as the lenses in our eyes focus the light onto our retinas. Then the shutter closes again so that no more light reaches the film. The whole process usually takes just a fraction of a second.

A still film camera is made of three basic elements: an optical element (the lens), a chemical element (the film) and a mechanical element (the camera body itself). As we’ll see, the only trick to photography is calibrating and combining these elements in such a way that they record a crisp, recognizable image.

There are many different ways of bringing everything together. In this article, we’ll look at a manual single-lens-reflex (SLR) camera. This is a camera where the photographer sees exactly the same image that is exposed to the film and can adjust everything by turning dials and clicking buttons. Since it doesn’t need any electricity to take a picture, a manual SLR camera provides an excellent illustration of the fundamental processes of photography.

The optical component of the camera is the lens. At its simplest, a lens is just a curved piece of glass or plastic. Its job is to take the beams of light bouncing off of an object and redirect them so they come together to form a real image — an image that looks just like the scene in front of the lens.

But how can a piece of glass do this? The process is actually very simple. As light travels from one medium to another, it changes speed. Light travels more quickly through air than it does through glass, so a lens slows it down.

When light waves enter a piece of glass at an angle, one part of the wave will reach the glass before another and so will start slowing down first. This is something like pushing a shopping cart from pavement to grass, at an angle. The right wheel hits the grass first and so slows down while the left wheel is still on the pavement. Because the left wheel is briefly moving more quickly than the right wheel, the shopping cart turns to the right as it moves onto the grass.

The effect on light is the same — as it enters the glass at an angle, it bends in one direction. It bends again when it exits the glass because parts of the light wave enter the air and speed up before other parts of the wave. In a standard converging, or convex lens, one or both sides of the glass curves out. This means rays of light passing through will bend toward the center of the lens on entry. In a double convex lens, such as a magnifying glass, the light will bend when it exits as well as when it enters.

This effectively reverses the path of light from an object. A light source — say a candle — emits light in all directions. The rays of light all start at the same point — the candle’s flame — and then are constantly diverging. A converging lens takes those rays and redirects them so they are all converging back to one point. At the point where the rays converge, you get a real image of the candle. In the next couple of sections, we’ll look at some of the variables that determine how this real image is formed.

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HOW LONG DOES IT TAKE TO SHEAR A SHEEP?

Cutting or shaving the wool off of a sheep is called shearing. Shearing doesn’t usually hurt a sheep. It’s just like getting a haircut. However, shearing requires skill so that the sheep is shorn efficiently and quickly without causing cuts or injury to the sheep or shearer. Most sheep are sheared with electric shears or shearing machines. The fleece is removed in one piece.

Some sheep are sheared manually with scissors or hand blades. While some farmers shear their own sheep, many hire professional sheep shearers. In many countries, including the United States, there is a growing shortage of qualified sheep shearers. Many states hold annual sheep shearing schools.

A professional shearer can shear a sheep in less than 2 minutes. The world record is 37.9 seconds. The record was set in 2016 by Ivan Scott from Ireland. Scott set another record, shearing 867 lambs in just 9 hours. Matt Smith from New Zealand owns the record for shearing the most ewes, 731 ewes in 9 hours. The most Merino ewes sheared in 8 hours is 497, a record set by Lou Brown from New Zealand. The blade shearing record was set over 100 years ago when legendary shearer Jackie Howe sheared 321 sheep in 7 hours and 40 minutes.

In 1957, a New Zealander sheared a sheep in just 47 seconds!

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WHO WAS THE FIRST PHOTOGRAPHER?

The first person to take a photograph was a Frenchman, Joseph Nicephore Niepce, in 1822. However, as is often the case with new inventions, many other scientists had been experimenting with light, lenses and light-sensitive chemicals. Working with Niepce was a man called Louis Daguerre, who later improved on Niepce’s process. Some early photographs were called daguerreotypes.

Around 1717 Johann Heinrich Schulze captured cut-out letters on a bottle of light-sensitive slurry, but he apparently never thought of making the results durable. Around 1800 Thomas Wedgwood made the first reliably documented, although unsuccessful attempt at capturing camera images in permanent form. His experiments did produce detailed photograms, but Wedgwood and his associate Humphry Davy found no way to fix these images.

In the mid-1822s, Nicephore Niepce first managed to fix an image that was captured with a camera, but at least eight hours or even several days of exposure in the camera were required and the earliest results were very crude. Niépce’s associate Louis Daguerre went on to develop the daguerreotype process, the first publicly announced and commercially viable photographic process. The daguerreotype required only minutes of exposure in the camera, and produced clear, finely detailed results. The details were introduced to the world in 1839, a date generally accepted as the birth year of practical photography. The metal-based daguerreotype process soon had some competition from the paper-based calotype negative and salt print processes invented by William Henry Fox Talbot and demonstrated in 1839 soon after news about the daguerreotype reached Talbot. Subsequent innovations made photography easier and more versatile. New materials reduced the required camera exposure time from minutes to seconds, and eventually to a small fraction of a second; new photographic media were more economical, sensitive or convenient. Since the 1850s, the collodion process with its glass-based photographic plates combined the high quality known from the Daguerreotype with the multiple print options known from the calotype and was commonly used for decades. Roll films popularized casual use by amateurs. In the mid-20th century, developments made it possible for amateurs to take pictures in natural color as well as in black-and-white.

The commercial introduction of computer-based electronic digital cameras in the 1990s soon revolutionized photography. During the first decade of the 21st century, traditional film-based photochemical methods were increasingly marginalized as the practical advantages of the new technology became widely appreciated and the image quality of moderately priced digital cameras was continually improved. Especially since cameras became a standard feature on smartphones, taking pictures (and instantly publishing them online) has become a ubiquitous everyday practice around the world.

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WHAT IS SILK MADE FROM?

Natural silk is spun as a thread by silk-worms. They use it to form a cocoon. Unlike other natural threads, the silk-worm’s thread is very long — up to one kilometre (0.62 miles). Traditionally made in Asia, silk was such a sought-after textile that the route from Europe to the East became known as the Great Silk Road.

Silk is made from Silkworms (known as Bombyx mori) and Bombyx mori eats mulberry leaves. The silkworm is the larva or caterpillar of the domestic silk moth, Bombyx mori’. Fine silk and Bombyx mori is interconnected worm or moth.

When mulberry leaves put forth their leaves – this is the time that these silkworms are born- these helpless worms feed on the leaves. In the silk manufacturing process, they are kept in a tray filled with carefully selected tender and succulent mulberry leaves for about 25-28 days. It is said that a worm eats about 10,000 times its body weight of mulberry leaves and increase their weight to almost 5000 times in this short span.

Sericulture refers to Rearing of silkworm for the production of silk. When it is fully grown, it climbs onto a twig in the natural environment. In sericulture, it is placed on a special frame. If you are growing it at home you will have to give it a bamboo/plastic/metal frame, for the larvae to weave his cocoon around it.

The worm starts to spins a cocoon around itself. This cocoon is made with a sticky substance that comes out of an opening in its underlip. This is made by mixing a fibroin protein compounds that come out of its salivary glands and another substance called sericin (silk gum) in its mouth.

As it comes out, this sticky substance solidifies when in contact with air into the silk fiber. In three days it makes thousands of meters of this fiber. For about 10-15 days the silkworm will be a pupa inside this self-made home. Then it undergoes metamorphosis into a furry winged moth.

The moth will eventually worm itself out of the cocoon – but this is not allowed to happen unless the moth is required to breed eggs. This will damage the silk fibers in the cocoon or cut it short, so these worms are killed by putting them in boiling water /oven. When the worms are put in boiling water the sticky sericin coating of the silkworm also dissolves.

Sometimes two silkworms will nest together forming a single cocoon producing fibers that are thick and thin – the fabric made from these fibers are called Dupioni silk Cocoons are sorted according to their color and texture. The single cocoon in carefully unraveled and the fiber is wound /reeled on a spool. Usually, about 6 filaments are reeled together to create a thread. The single strands of the thread may be doubled and twisted for strength.

This long thin fiber is silk with many impurities. The fibers are taken out and washed thoroughly to remove any residue/gum etc. The yarns are boiled in a soap solution to remove the natural silk gum or sericin. It has to undergo many washes and treatments before it is usable for weaving. Thus you get your silk filaments ready to be weaved into fabric.

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HOW ARE FABRICS PATTERNED?

There are two main ways of patterning fabrics. By using coloured threads in the knitting or weaving, patterns can be made in the fabric itself. This is a very easy way to create stripes and checks, and it is quite cheap to use lots of colours, so the resulting fabric can be very bright. Another method of patterning fabric is to print it, using special dyes. This may be done by big rollers or by squeezing dye through patterned screens. Since only one colour can be printed at a time, each additional colour adds to the cost.

Fabric patterns come in all kinds of colors, shapes, sizes, repeats, and schemes. That’s why picking the right fabric patterns—and mixing prints—can be tricky. So we called on a handful of our favorite designers to help us break down the basics behind some of the most popular fabric patterns out there. From chevron to polka dots and beyond, here’s everything you need to know about themost common fabric patterns. Once you know the names of these patterns and what defines each of them.

Basketweave

Designed to resemble the crisscross weave of a basket, basketweave patterns are either woven or printed onto a fabric to create a symmetrical effect. “As a traditional woven, a basketweave fabric can introduce warmth to a room to balance out more neutral and subdued tones,” says Ella Hall, founder of Stitchroom. “When used correctly, the handmade texture is a great contrast to a muted palette and can also complement a minimalist style.”

Brocade

“A typically shuttle-woven fabric most commonly made with silver or gold thread, brocade has a raised appearance similar to embroidery,” No surprise then that you’re most likely to find brocades in more traditionally designed space. “The ornamental features of this fabric pattern bring a rich and elegant touch to accentuate classic furniture pieces,” she adds.

Checkered

One of the most popular and instantly recognizable patterns on the market, checked, or checkered, fabrics feature a simple checkerboard-style design with alternating colored squares. “Checked fabric has traditionally worked well in farmhouse modern and country design, and while it might originate there, a more contemporary twist has recently brought the countryside to more urbanized spaces.” “This fabric trend is perfect for banquettes with high traffic trying to make a statement through its upholstery fabrication.”

Chevron

Marked by a pattern of zigzagging stripes, chevron fabrics have long been a favorite of designers looking to infuse contemporary flair into a subdued space. “Modern interpretations of the chevron motif have brought new life to the classic that can sometimes feel overwhelming.” “Try selecting a chevron with subtle tonal differences or a textured chevron to contribute to your sofa’s pillowscape.”

Damask

“Martha Stewart is a big fan of damask, and this rich-looking fabric has been used everywhere from English castles to Park Avenue apartments,” Okin says. “A reversible, print-heavy look, damask is typically filled with swirling patterns and looks beautiful in jewel tones. This look works well when executed in silks and taffetas in dramatic, grand rooms.”

Chinoiserie

Drawing from traditional Chinese motifs, chinoiserie style fabrics often feature elaborate scenes of florals, animals, pagodas, and children. “Chinoiserie is a romanticized print that adds a level of sophistication to upholstery,” Hall says. “Whether with curtains, chair upholstery, or throw pillows, chinoiserie fabrics always make a decorative statement.”

Flame Stitch

“Also known as bargello or a Florentine stitch, flame stitch needlework combines long, vertical stitches and bold colors into zigzagging peaks and valleys,” Okin says. “This look was very popular in the 1960s and has a psychedelic element to it, so it’s perfect for funky spaces with a retro vibe.”

Greek Key

“The Greek Key pattern is as old as time really, and it’s more traditional than anything I tend to use,” Roth says. “The pattern is made from a continuous line that repeatedly bends back on itself to create squared spirals. I think of it as a border pattern more than anything else and work well on curtains or bed linens.”

Houndstooth

“The name houndstooth comes from whoever invented the pattern, thinking the checks that make it up look like dog’s teeth, but I think they look more like little bugs,” Roth says. “In my opinion, the pattern is quite handsome and masculine, and it’s a strong accent in a room. I’d use it on a pillow or throw blanket in a study.”

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