Light and stuff.

January 24, 2018

 

 

Perhaps too many times we hear the words "I don't understand light."

 

Scarier still... 

 

"I'm a photographer but I can't light."

 

If a person who cannot play violin attempts to play that most exquisite sounding and difficult to play instrument; scratching the bow over some quite innocent strings, that person may produce sound, though it is questionable they will create music.

 

Perhaps even closer to the point is that, though a chef may cook many a delicious meal, they need not be a farmer or fisherman. They should though have a thorough understanding of the food ingredients they use and also a sound knowledge of things thermal. A good chef will get the temperature right and know well the boiling point of diverse substances and hopefully know when food ingredients burn. A point to remember also is that a chef may have the best pots, pans and other cooking utensils but a five star Michelin chef those tools do not make.

 

A camera is a tool that helps us manipulate light to and with the aid of a receptor, create a permanent image of an event or place. Humans are great story tellers and our ability to tell stories has, arguably I suppose, advanced us well beyond other species. Photographs are visual stories. Aunty Flo's photograph of herself atop the Eiffel Tower tells us a story. Though it's a very simple plot the photograph tells us that Aunty Flo has been to the Eiffel Tower. Who would have known?

 

Light is a camera's "fuel" and the photographers life blood.

 

You don't have to be a chemical engineer to understand which fuel to put in your cars fuel tank but you will need to know the difference between; four stroke petrol, two stroke petrol, diesel and kerosene. Put two stroke fuel in your your four stroke car engine and your car will blow a lot of smoke for a while and finally give up the ghost; your travel hopes dashed.

 

So one does not necessarily need to be a scientist to be a photographer. In some cases being "over scientific" crushes creativity but beyond doubt photography involves science. Don't fear light or be afraid to attempt to manipulate it.  Although ultra violet light and infra red light can heat or even burn our skin and, if the light is bright enough, burn our eyes, apart from those instances light is pretty harmless stuff.

 

Light is very cool shit.

 

And here are some hopefully easily understood reasons why. 

 

Light, or in this case white light, is made up of all colours of the rainbow and like paint those colours can be mixed achieving millions of different blends. 

 

Unlike sound, light can travel through a vacuum and except for the lights' source, light is invisible. Unless it lands on something.

 

Once Light starts to travel away, or radiate, from its source; a source which could be a candle or could be a star or any of many light creating reactions, it just keeps on going and going and going. Going on forever unless it bumps into something that won't let it pass through and reflects the light. Or that something, better known as matter, may only let a portion of the light through itself, as with sunglass lenses. Clear glass and sometimes clear plastics can be shaped to form a lens. As is the case with a magnifying glass, light can also be concentrated often causing heat. Lenses can distort lights path in many ways and that ability is well utilised in camera lenses. 

 

Some forms of matter or substances, like tracing paper, allow a proportion of light through them but confuse the direction of the light; scattering it about. This behaviour is known as translucent's and creates diffused light and creates soft to almost no shadowing. A spot light emits very "sharp" or "specular" light and a very sharp edged shadow is created. An X Ray viewing box is very diffused light and creates soft shadows. You will see your shadow very distinctly on a sunny day but if a cloud passes between you and the sun the general amount of light is reduced and your shadow will all but disappear.  

 

Once light sets off, on its eternal journey from whatever reaction caused it, it expands outward (propagates) in all directions. It also immediately and with no acceleration delay, achieves a speed of 299,792 kilometres per second. The speed of light. The fastest thing in the universe.

 

Given a great enough distance and a great enough mass of matter, gravity can can affect light and bend it. Steven J Hawking would be far better at explaining that oddity and besides it's not going to affect the average person with a camera or photographer.

 

As we know, some matter, or substances, love light and keep it all to themselves while others don't care for it and reflect it away. Even others like to play with it's behaviour on its long journey. Black surfaces adore light and keep all, or just about all of it, to themselves. White surfaces don't want anything to do with light and reflect it. Yet other substances prefer one or two or more colours that make of white light and reflect the others away. Tree leaves are green because the matter that makes up the leaves doesn't like green and reflects it. There are millions of variables of colour and the human eye can perceive between seven and ten million.

 

Now for the, hopefully not to scary, tale of a most formidable sounding thing; The electromagnetic spectrum.

 

Visible light lies within the Electromagnetic Spectrum, best described as "a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light."

 

Photons are not matter. They have no mass, but they sure as hell behave like they do. 

 

A portion of the Electromagnetic spectrum we know as light is visible to the eye. Some animals can discern more colours than others and some see in a different range or perhaps specific part of the electromagnetic spectrum. Some poor creatures apparently can't see colour at all and find it most difficult at traffic signals. Bee's have great ultra violet vision and flowers look completely different to a bee. 

 

There's lots of other radiation types in the Electromagnetic Spectrum like; Gamma Rays, Radio Waves, Microwaves and many more including X-Rays which are also used in medical photography. Infra Red which can be used for thermal imaging and night vision equipment. It's almost like Infra Red is so red we can't see it. Light in other words is visible radiation.

 

For now lets leave the electromagnetic spectrum and all its many forms of radiation out of the discussion and concentrate on that part visible to the naked eye.

 

The part of the electromagnetic spectrum we call visible or visible light and the part we use to make photographs. 

 

Earths star, our Sun, the greatest source of light in our cosmic neighbourhood personally assisted with the creation of all life on Earth. Although a few species headed to the dim depths of the oceans and others to dark above ground caves, even they are children of the Sun. The offspring of light.

 

It should always be remembered that the Earth is solar powered and always has been.

 

And without light there is no photography.

 

The word photograph is derived from the Ancient Greek words "phos" meaning light and "graphe" drawing or writing.

 

A photograph is a light drawing. 

 

Photographs, in the physical sense, were originally created using chemicals called silver halides. These weird "salts" of silver, best described as a powder, have a habit of turning into metallic silver when exposed to light. How exactly, or even why, no one really knows but silver halides behave in such a way despite scientists best efforts to understand the process. There are three forms of silver halide used, for varying reasons used in chemical photography; Silver chloride, silver bromide and silver iodide. 

 

Humans learned to use the unusual properties of silver halides to create the original black and white photographs, otherwise known as monochromatic. Just smear the silver halides on some gelatine, paper or glass, and voila, you have film. Except for a couple of odd processors for rendering colour, black and white film was all humanity had for the best part of a century but, unquestionably, photography had a huge impact on humanity and the knowledge of ourselves.

 

Then came colour photography, but even chemical colour photography used/uses silver halides' odd properties to create photographs. Briefly explained three sandwiched layers of silver halides were most intriguingly and quite brilliantly fused together. Each of these very thin layers of silver halide was sensitised to either red, green or blue light. If the silver halides were exposed to their specific colour sensitivity the halides in that part would commence turning into metallic silver. 

 

Once the three black and white layers of silver halides have been "developed" in a quite routine black and white developer (or first developer) the film would then undergo colour development where tiny things called dye couples which were attached to the silver halide would rupture, but only if their corresponding halide had turned to silver. 

 

Technicolour, an early motion picture form of colour photography used a different system where three rolls of black and white film were exposed at the same time. A prism behind the lens would split the light into three parts, each part falling onto each of the three rolls of film. Each roll of film sensitised to either red green or blue. All three rolls of black and white film would then be processed, then further exposed onto a single roll of film, dyes were introduced to match the colour each of the rolls of film was sensitised to finally producing a colour "print". Of course it wasn't a paper print but another roll of film which could be projected.

 

A highly complex and delicate procedure Technicolour was extremely expensive. Hence low budget films of the past were usually black and white and colour saved for more expensive productions. Technicolour cameras were to say the least, enormous and cumbersome and a huge amount of light required to produce a "good" exposure. Gone with the Wind and The Wizard of Oz, produced in the late 1930's are examples of the first use of Technicolour. Later down the track "colour negative" film was invented and Technicolour went by the wayside. The invention of Colour negative films, such as "Ektacolor" meant that colour prints (on paper) could be made and colour film became available to the broader market.

 

 

 

 

Some dudes playing about with an early Technicolour motion picture camera. The camera is housed within a "blimp" which quietened  the amount of noise generated by the camera for sound recording purposes.

 

 

 

 

 

To think that the Technicolour process worked at all is amazing and I personally love the look of the stuff. The Kodak invented film "Kodachrome", was yet another form of colour film used in the early years of colour photography. It, like later forms of colour film such as "Ektachrome", were colour reversal films that had no true negative.

Then came digital photography.

 

Digital photography is exactly the same as photography ever was. It's my belief that this fact should be clearly understood. The only real difference between digital and chemical (analogue) photography is that by use of an electric current photons are turned into electrons rather then silver halides being turned into metallic silver. Miniaturisation of digital cameras and their components of course means cameras can be a lot smaller but again the photography remains the same.  

 

Light, which we know is made up of photons, passes through a lens as is the case with just about all cameras except maybe pinhole cameras where there is no lens; just a hole or "aperture". Once the photons travel through the lens and the lens has its way with them, bending the photons direction to its will,  the photons land on an array of electronic photodetectors, better known as a "sensor". It's here by means of some pretty whizz-band technology that your story is permanently recorded. 

 

Apart from the use of a digital sensor all the science of photography remains the same. Sure there's additional gizmos hanging off cameras, many assisting with correct focus and "accurate" exposure levels; measurement of our old friend light. There's also stuff that helps you operate a camera remotely, takes voice messages and tells you where you are on planet Earth. I'm looking forward to cameras that can tap-dance. But if you want to create "good photographs" understanding light and having the knowledge to; work with it, create it or even manipulate, is essential. 

 

Have no fear light.

 

Light is our friend.

 

There is little which is more important in nature than light.

 

Introduce yourself to it and you'll grow to love the stuff. 

 

 

 

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