Camera basics

The camera I use is a Cannon 7D its specifications are:

18MP APS-C CMOS sensor

8fps shooting

ISO range up to 12800

100% Viewfinder

19 cross-type AF points

iFCL metering system

Dual "DIGIC 4"

Full HD movie

Integrated Speedlite Transmitter

3” Clear View II LCD

Magnesium alloy body with environmental protection

My camera's basic functions are mapped to buttons on the rear and top of the camera.

The wheel to the right of the screen controls the aperture.

A aperture is a hole or opening through which light can flow. On a camera this can be changed to allow more light in (f/1.4) or less light in (f/32)

However the size of your aperture directly effects your depth of field.

Your depth of field is the distance or area of your photograph that is clear. If you have a large depth of field a large area of your photograph is sharp however, this requires a very small camera aperture.

But a small aperture will require a long shutter speed. So a balance will need to be found. Likewise a shallow depth of field uses a large aperture and requires a much shorter shutter speed.

The wheel on the top right controls the shutter speed.

CD Brief

Introduction
For this brief we were given 1 day to think of a song and then create a single CD cover for that song.

The song i chose was Coldplays - Viva La Vida

Research & image development
My first step was to watch and listen to the song and the video. The video is shot as if it is a moving painting so i decided that the cover should also reflect this. I also noticed that the colours were highly contrasting and that my image should reflect this.

Through listening to the song there was one specific line in it that stood out to me "And I discovered that my castles stand. Upon pillars of salt and pillars of sand". I decided that the main focus of my cover should be some form of imposing castle. I did a quick search on google and found Houghton tower about 10 miles away.

This is one of the pictures i took and felt this was best suited for my needs. I then cropped the image down to fit the size of a CD cover (1080px x 1080px).

Next I slightly upped the contrasts again before using a photoshop filter effect called "Fresco". This then gave the look of a painting.

I added even more texture to the painting by downloading a cracked paint brush from Devient Art. I added these from the edges to make sure it continued the effect of a painting. Finally to keep with the theme of a painting I downloaded a brush font from a free font resource called Da Font. I added the text an in the end came up with two final text fomats. One with a plain white text and one with coloured text. In the end i chose the coloured text as my final CD cover image.

Work Flow

This is a detailed mapping of how I work. From initial idea conception. Right through until print.

Initial ideas & conception

Once I have been given the outline of my brief I will then attempt to visualise the end result. However if i have no clear idea of the ending result I find using a flow chart. (Below)

I will then settle on a final idea from the sheet and plan it in more detail. (Below)

If however I was working a set brief with no room for my own interpretation then I would move straight onto the next section.

Studio set up & equipment set up

During this next stage I will decide what equipment I will be using as well as choosing which camera and lenses are best for this shoot. During the course of the shoot it may well require the use of a verity of lenses. So it is essential to have these at hand.

A Cannon 350D & 7D with a selection of lenses

Image Upload & saving

Next I will upload the RAW & JPG images up onto my Macbook.

My universal card read and 2 x 4GB Compact Flash cards

These images will then be uploaded into Adobe lightroom.

My lightroom catalog

This is the most efficient way to view and select my images. As well as it being the best way to save them as they are instantly added to my catalog. However Lightroom editing employs destructive save system. This means that when I start to edit my images, I am editing the original image. So getting back to the original if I dont like the results cant be quite difficult, but not impossible.

Contact sheet?

If i feel i need to make a printable contact sheet I can do this at this time by using Photoshop CS4 or Adobe Bridge. CS4 is the easiest method to use.

A contact sheet done in CS4

Saving RAW images

I will then save these raw unedited images onto one of my 2 x 500GB hard drives.

Left: 500GB wired HD - Right 500GB unwired

And then add them to my dropbox. A dropbox is a internet server of your images. It is a secure location controlled by a professional company, who keep 100's of servers in specially built cool rooms. It is my 3rd and final redundancy. This in case I lose my Macbook and my external hard drives. Either through flood, fire or theft.

This also means I have access to my images from anywhere in the world. As well as the ability to upload to my dropbox from any location in the world.

My dropbox file list

Photoshop? Or Lightroom editing?

Now I will decide if my pictures require photoshop or lightroom editing. If I want a quick controlled even look on a large number of images I will use lightroom. If my pictures require detailed editing I will use photoshop CS5, as I feel like i have a greater control over just how exactly my images are edited.

Photoshopping my image

Once my image is photoshopped i will save it/them into a folder on my Mac, named for ease of identification.

My file system on my Macbook Pro

Re-save all edits

I will now resave every edit I have done. Making sure it can easily be identified for quick acsess.

Utdshrt-fnl-crppd.jpg

This reads to me 'United Shit - Final image - Cropped

These will now be saved to my external hard drives. With the best images being saved to my drop box.

Save for delivery & Upload

My final images will now be saved onto a pen drive for delivery to whoever requires them. I will then upload my pictures to Flickr.com. Making sure to label them all up correctly.

My Flickr page

I will then upload the highest quality pictures to my website. www.ThomasEvansPhotography.co.uk for use in my portfolio.

My website portfolio

Images will then finally be watermarked and added to my facebook 'like' page. Which contains links to my website and Flickr account for none watermarked viewing.

My work flow chart

I will follow the steps on this chart to determine my next course of action. fsfsf

Face Flipping.

We set up the studio to take some portrait shots. I used a very basic light set up, with one light with a diffuser on and one reflector to light the opposite side of the face to avoid any shadows that would make the post processing difficult to handle and pull off.

This is one of the photos I took. The next stage was to clean up the image and any rough areas on the face.

The next stage was to select half the image with the select tool. The cmd + C to copy, then cmd + p to paste the copy as a new layer.

Next I flipped and aligned the image, using the spot-healing tool to remove any visible joining lines that could be seen.

I then repeated this process with the other side of the face taking care to align it all correctly so to avoid any harsh lines showing. I then pasted all 3 images (Left flip, original and right flip) into one image and posted it as my final picture onto Flickr.

Final image.

Web design and Promotion

Create your own website

A website in 2010 is perhaps the single most important tool you can have to sell yourself as a photographer. With over 500 billion documents and 2,024 webpages and 109.5 million websites the internet is a very big sea and you are a very, very small Plankton. However by following these small steps, you can help yourself get more noticed and eventually become Krill sized.

Where to start

Unless you have time to study PHP and other web design codes you are not going to be able to script your own website. However there are many tools out there, most of them are free. To help you create a good website.

www.webs.com - This is a great tool if you have no idea about web design or flash. It has plenty of great templates for you to use.

Now you will want to upgrade your website to it has its own domain, so people know its you. Any webs/youdomain names look tacky and unprofessional and wont bring any traffic to your site. Web hosting and domain names are not free, and the webs package comes with a free domain. The prices are very reasonable and are what you would expect to pay for web hosting of this level.

www.wix.com is the second website. This uses flash primarily and requires a very basic understanding of web design. You can have as little or as greater control over the design as you like.

Again pricing is around the same mark as before. However these packages come with a free domain as well as $75 of google advertiseing and $50 facebook advertising. These are very useful for bringing visitors to your website.

Facebook

Facebook is a social network service and website launched in February 2004 that is operated and privately owned by Facebook, Inc. As of July 2010 Facebook has more than 500 million active users. Users may create a personal profile, add other users as friends and exchange messages, including automatic notifications when they update their profile. Additionally, users may join common interest user groups, organized by workplace, school, or college, or other characteristics.

Facebook is a useful tool for advertising yourself as a photographer. With 500 million users worldwide you can almost force your content onto people. You are guaranteed to get visitors to your website.

Advanced Camera details

Exposure Controls

When you take a picture, you "expose" a film or sensor to light. The two parts which work together to control your exposure are the APERTURE and SHUTTER. Some "Point and Shoot" cameras select these automatically, but more expensive digital cameras enable you to set these manually, or to "program" them for certain shooting conditions.

Shutter Speed

In still cameras, the term shutter speed represents the time that the shutter remains open when taking a photograph. Along with the aperture of the lens (also called f-number), it determines the amount of light that reaches the film or sensor. Conventionally, the exposure is measured in units of exposure value (EV), sometimes called stops, representing a halving or doubling of the exposure.

Multiple combinations of shutter speed and aperture can give the same exposure: halving the shutter speed doubles the exposure (1 EV more), while doubling the aperture (halving the number) increases the exposure by a factor of 4 (2 EV). For this reason, standard apertures differ by √2, or about 1.4. Thus an exposure with a shutter speed of 1/250 s and f/8 is the same as with 1/500 s and f/5.6, or 1/125 s and f/11.

In addition to its effect on exposure, the shutter speed changes the way movement appears in the picture. Very short shutter speeds can be used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for artistic effect. Short exposure times are sometimes called "fast", and long exposure times "slow".

Adjustment to the aperture controls the depth of field, the distance range over which objects are acceptably sharp; such adjustments need to be compensated by changes in the shutter speed.

Standard Shutter speeds:

1/1000 s

1/500 s

1/250 s

1/125 s

1/60 s

1/30 s

1/15 s

1/8 s

1/4 s

1/2 s

1 s

Aperture

In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are, which is of great importance for the appearance at the image plane. If an aperture is narrow, then highly collimated rays are admitted, resulting in a sharp focus at the image plane. If an aperture is wide, then uncollimated rays are admitted, resulting in a sharp focus only for rays with a certain focal length. This means that a wide aperture results in an image that is sharp around what the lens is focusing on and blurred otherwise. The aperture also determines how many of the incoming rays are actually admitted and thus how much light reaches the image plane (the narrower the aperture, the darker the image for a given exposure time).
An optical system typically has many openings, or structures that limit the ray bundles (ray bundles are also known as pencilsof light). These structures may be the edge of a lens or mirror, or a ring or other fixture that holds an optical element in place, or may be a special element such as a diaphragm placed in the optical path to limit the light admitted by the system. In general, these structures are called stops, and the aperture stop is the stop that determines the ray cone angle, or equivalently the brightness, at an image point.
In some contexts, especially in photography and astronomy, aperture refers to the diameter of the aperture stop rather than the physical stop or the opening itself. For example, in a telescope the aperture stop is typically the edges of the objective lens or mirror (or of the mount that holds it). One then speaks of a telescope as having, for example, a 100 centimeter aperture. Note that the aperture stop is not necessarily the smallest stop in the system. Magnification and demagnification by lenses and other elements can cause a relatively large stop to be the aperture stop for the system.
Sometimes stops and diaphragms are called apertures, even when they are not the aperture stop of the system.
The word aperture is also used in other contexts to indicate a system which blocks off light outside a certain region. In astronomy for example, a photometric aperture around a star usually corresponds to a circular window around the image of a star within which the light intensity is summed.

The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film's or image sensor's degree of exposure to light. Typically, a fast shutter speed will require a larger aperture to ensure sufficient light exposure, and a slow shutter speed will require a smaller aperture to avoid excessive exposure.

A device called a diaphragm usually serves as the aperture stop, and controls the aperture. The diaphragm functions much like the pupil of the eye – it controls the effective diameter of the lens opening. Reducing the aperture size increases the depth of field, which describes the extent to which subject matter lying closer than or farther from the actual plane of focus appears to be in focus. In general, the smaller the aperture (the larger the number), the greater the distance from the plane of focus the subject matter may be while still appearing in focus.

The lens aperture is usually specified as an f-number, the ratio of focal length to effective aperture diameter. A lens typically has a set of marked "f-stops" that the f-number can be set to. A lower f-number denotes a greater aperture opening which allows more light to reach the film or image sensor. The photography term "one f-stop" refers to a factor of √2 (approx. 1.41) change in f-number, which in turn corresponds to a factor of 2 change in light intensity.

Aperture priority is a semi-automatic shooting mode used in cameras. It allows the photographer to choose an aperture setting and allow the camera to decide the shutter speed and sometimes ISO sensitivity for the correct exposure. This is sometimes referred to as Aperture Priority Auto Exposure, A mode, Av mode, or semi-auto mode.

Typical ranges of apertures used in photography are about f/2.8–f/22 or f/2–f/16, covering 6 stops, which may be divided into wide, middle, and narrow of 2 stops each, roughly (using round numbers) f/2–f/4, f/4–f/8, and f/8–f/16 or (for a slower lens) f/2.8–f/5.6, f/5.6–f/11, and f/11–f/22. These are not sharp divisions, and ranges for specific lenses vary.

ISO Speed

ISO is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system.

Relatively insensitive film, with a correspondingly lower speed index requires more exposure to light to produce the same image density as a more sensitive film, and is thus commonly termed a slow film. Highly sensitive films are correspondingly termed fast films. A closely related ISO system is used to measure the sensitivity of digital imaging systems. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality (via coarser film grain or higher image noise of other types). In short, the higher the film speed, the grainier the image will be.

Metering

We talked in some detail about exposure in three earlier sections so by now you'll understand how shutter speeds, apertures and ISO all combine to affect the brightness of an image. Naturally, different conditions will lead to differing amounts of light being available and therefore a decision must be made regarding which shutter speed and aperture combination to use - for this an exposure meter is used. This device, be it a dedicated device or one built into your camera, simply measures the amount of light available which is then converted into aperture and shutter speed.

Different Types of Light Meter

Light meters may be in-camera light meters or handheld light meters. All modern cameras have built in light meters but there can be advantages to using handheld light meters on occasion. We'll cover in-camera light meters and their various options in a moment but first we'll touch upon the different types of handheld light meters. Handheld light meters typically fulfil one or more of the following functions:

reflected light metering
incident light metering
flash metering

Reflected Light Metering

The meter that is performing a reflected light reading is measuring the light reflected off your subject. You point the light meter at your subject and it tells you what the exposure would need to be in order to render that subject at a mid grey (typically referred to as 18% grey). This type of meter will give you different exposure results for a black subject or a white subject as it only tries to make an exposure to make things grey. It has no way of knowing if your subject is black, white or somewhere in between so it just measures the light coming off the subject and assumes the elements of the image will average out to be grey.

At its most basic level this is how an in-camera meter operates.

A special type of reflective light metering device is called a spot meter. This measures the light reflecting off a very small area of your subject, a small 'spot' if you will. To use a spot meter you aim it at a part of your subject that you wish to appear to be mid-grey and set your exposure as it tells you. Alternatively you can point it at a darker or lighter portion of your scene and adjust the exposure accordingly (more on this later).

Incident Light Metering

With an incident light meter you measure the strength of the light source. To do this you would hold the meter in front of your subject and point the meter at the source of light to take a measurement. This type of metering avoids the complication caused by your subject being of a reflective nature other than mid-grey as it is measuring the light totally independent of the shade or colour your subject is.

Flash Metering

A flash meter is a special type of incident light meter. A flash meter works in just the same way as described above except that it will automatically trigger your studio flash, take a reading while the flash is illuminated and tell you what aperture is needed for your currently selected ISO (shutter speed does not matter as it will be described in the 'Flash Photography' section of this book).

In-Camera Light Metering

Number 16 is the cameras built in EV meter.

As mentioned, an in-camera light meter is taking reflective light readings through the lens from the scene the camera is pointed at. If your camera is in an automatic mode the light meter will enable your camera to automatically select the exposure based on the scene it is measuring. If it is in manual mode the light meter will tell you if it thinks the picture will be under-exposed or over-exposed. Modern cameras come with at least one of the following metering modes (not to be confused with exposure modes - metering modes usually reside somewhere in the menu system):

centre weighted average metering
intelligent metering (somtimes called evaluative, matrix or multi metering)
partial metering
spot metering

Your camera may come with all of these modes. This is what they do.

Centre weighted average metering measures the light across the whole scene but pays more attention to the brightness of the scene in the centre. This was the most common type of metering on film SLR cameras and many people continue to use it as it is easy to understand and predict when it may be fooled into providing an incorrect meter reading.Intelligent metering is called something different by different manufacturers. Canon call it evaluative, Nikon call it matrix. It works by evaluating the whole scene and using an algorithm to try to identify what the scene is and therefore what the exposure should be. Whilst this mode is generally quite successful, some users choose to avoid it as the manufacturers don't publish how it makes its decisions and therefore it can be a little harder to predict.

With Canon's implementation they bias the exposure reading to the currently selected focus point as they assume that the focus point will be placed over the main subject of the scene.Partial metering measures a smaller part of the scene than the previous two but a greater part of the scene than spot metering. Partial metering takes its reading from a circle covering approx the centre 9% of the frame.

Partial metering can be useful where there is a wide dynamic range in your scene and you want to ensure a certain part is exposed correctly, for example a spot lit actor on a dark stage.Spot Metering measures a small part of the scene typically 1% to 5% and is useful for being precise about where exactly in the scene you want your light meter reading to come from. This is always taken from the centre of the frame except on some professional level cameras when there may be an option to have it taken from the selected focus point.

How to read your in-camera light meter.

Whilst most of the following discussion will apply to evaluative/matrix type metering there may be times where that type of metering may behave differently than other metering modes. As mentioned above, this is because this type of light metering uses unpublished and probably fairly complex algorithms to decide on a correct exposure. For the most part the following information will be fine for that type of metering mode but if your camera meters in a way that isn't explained here while in that type of mode it's simply because it is trying to be clever!

Most, if not all, of the time you will be using your camera's in-built light meter. As we have mentioned this type of light meter is carrying out reflected light metering and is trying to render the scene so that it averages out to a mid-grey tone. It is surprising how often this works out just fine but this can mean scenes containing very bright or very dark elements can fool a camera meter into under or over exposing.

If the scene you are photographing contains very bright elements it may cause your camera to think it needs less exposure than it really needs for example:

a snow scene
a sunny day on a beach
a bride in a white wedding dress
a back-lit subject (i.e. where the light is behind the subject)

In these examples the camera will be trying to render your subject grey whereas they really need to be white or close to white. This will cause your meter to suggest the wrong exposure and if you listen to it you will end up with an underexposed picture. To rectify this you will need to tell your camera to overexpose by one or two stops. In manual mode to simply select an exposure where your camera meter is telling you it will be overexposed by one or two stops (depending on how much whiter than mid-grey your subject is), in an automatic mode you will need to use exposure compensation (see exposure part 4).

If the scene contains very dark elements your camera may over expose as it thinks there is less light than there is. Remember, it is trying to make your subject grey. If your subject is darker than that it will turn out too bright in your photograph as the camera tries to compensate. For example:

a close-up of a person wearing dark clothes
a person against a dark background such as a person lit by spotlights on stage.

In these circumstances you can adjust for your light meter's misreading of the situation in the same way as above. The only difference is this time you need to tell the camera to underexpose.

Grey Cards

Because light meters can be fooled by dark or light subjects, photographers sometimes use grey cards. These are, like the name suggests, cards that are grey. To be more specific they are cards that are designed to be the shade of grey that your light meter is looking for. Therefore if you take a light meter reading by pointing your camera at the grey card you should get the correct exposure. To make this work, the grey card needs to be in the same lighting conditions as the subject so you may ask your model (if you are taking a portrait) to hold the grey card close to his or her face while you take a spot meter reading from it to set your exposure.

If you don't want to carry your grey card around with you, you can use your hand. Take a reading off your grey card outside your home then take a reading of your hand. Your hand and grey card are likely to give different exposure results but as long as you know this then you can compensate in the field. For example, a white person may find that their hand and their grey card give a one stop different exposure with the hand apparently requiring one stop less exposure. This means that in the field someone like this can take a meter reading off their hand and adjust the exposure so the camera appears to overexpose by one stop.

What if none of these systems are working?

Natural light, as well as many scenes with artificial lighting, is predictable, so that exposure often can be determined with reasonable accuracy from tabulated values.

Exposure values (ISO 100 speed) for various lighting conditions

Advanced Techniques - The Zoning System

The Zone System is a photographic technique for determining optimal film exposure and development, formulated by Ansel Adams and Fred Archer in 1939–1940.

The Zone System provides photographers with a systematic method of precisely defining the relationship between the way they visualize the photographic subject and the final results. Although it originated with black and white sheet film, the Zone System is also applicable to roll film, both black and white and color, negative and reversal, and to digital photography.

Sources

http://www.azuswebworks.com/photography/camerabasics.html

http://en.wikipedia.org/wiki/Shutter_speed

http://en.wikipedia.org/wiki/Aperture

http://www.creativephotobook.co.uk/pg04007.html

http://en.wikipedia.org/wiki/Zone_System

http://en.wikipedia.org/wiki/Exposure_value#CITEREFANSI_PH2.7-1973

Colour Management

Color photography, especially color printing has always been a challenge. Photographers as renown as Ansel Adams have felt intimidated trying to produce worthy color prints of their work. Many sought refuge and remained in the safe world of B&W through out their career. The digital darkroom has given every photographer who so desires the power to print accurate, easily reproducible color prints of their images — assuming of course that they possess an understanding of human color vision.

The Nature of Light

Light is the basis of all photography. Without light, we are all left in the dark. But what is light? Light it turns out is a form of electromagnetic radiation (EMR), fluctuations of electric and magnetic fields which move through space as waves move over the surface of a pond. The electromagnetic spectrum includes radio waves , infrared, visible light, ultraviolet, x-rays and gamma rays.

Scientists classify EMR by its wavelength, the distance between two consecutive crests of a wave. Human eyes it turns out are only sensitive to the range that is between wavelength 780 nanometers and 380 nanometers in length. A nanometer is one billionth of a meter. These are very tiny waves! This very special area is called the visible spectrum or visible light. Most color photography deals only with the visible spectrum.

Wavelength of colors in the visible spectrum

In order to see a color print or anything for that matter, we must place it under a source of illumination. There are several common effects that are used to produce this illumination.

Incandescence

Solids or liquids heated to 1000 degrees K in temperature or greater emit light. K is short for Kelvin, the absolute version of Centigrade scale. Water boils at 373 K, so 1000 K is very hot! The tungsten filament light bulb is the commonest man-made source of light on earth, it glows at about 2854 K. The sun, is a natural incandescent source whose surface is at about 5800 K.

Phosphorescence

Phosphors are substances that absorb energy and re-emit light. The phosphor coating of a common florescent tube emits visible light when excited by energy released within the tube. An electric arc between the tubes electrodes creates ultraviolet light which excites the phosphor causing it to glow.

The problem for color photographers is that not all light sources are created equal! The spectral energy of these light sources varies greatly. The color content of the light source is usually described in terms of the temperature of an incandescent emitter which produces a color spectrum closest in color to that source. The higher the temperature the bluer the light. The lower the temperature the redder the light. Tungsten light bulb illumination is very orange compared to daylight. The color characteristics of the light source are referred to as its spectral power distribution.

The Nature of the Object

The color we perceive an object to be is determined by which wavelengths of light are absorbed or reflected by the object. Only the reflected wavelengths reach our eye and are seen as color. The leaves of most common plants absorb red, orange, blue & violet . At the same time they reflect all the green wavelengths and are therefore seen to be green in color. These characteristics of the object are referred to as its spectral reflectance.

The Nature of the Human Eye

The human eye is the last link in the chain of color vision. The human eye has a simple two element lens. The cornea is the front or outer element and the lens is the back or inner element. The amount of light entering the eye is controlled by the iris which lies in between the two. The light passes through a clear gel called the vitreous humor and creates an inverted image on the retina at the back of the eyeball .

The retina is the light sensitive part of the eye. Its surface is coated with millions of photoreceptors. These photoreceptors sense the light and pass electrical signals indicating its presence through the optic nerve to stimulate the brain. There are two types of photoreceptors, rods and cones.

The rods are sensitive to very low levels of light but are monochromatic and cannot see color. That's why at very low light levels, humans see things in B&W.

The retina contains three types of cones. Different light sensitive pigments within each of these three types responds to different wavelengths of light. Red cones are most stimulated by light in the red-yellow spectrum. Green cones are most stimulated by light in the yellow-green spectrum. Blue cones are most stimulated by light in the blue violet spectrum. This phenomena describes the spectral sensitivity of the eye.

Spectral sensitivities of the red, green and blue cones.

To make the eye "see" any color of the spectrum it is only necessary to stimulate the three types of cones in a manner similar to the way the actual color would.

It is not necessary to actually produce the color of light! This is exactly how a CRT monitor works on a computer or TV. If you look closely at the face of your TV with a 4x loop you can see the individual RGB color phosphor stripes glowing. A color TV or computer monitor is really not a color device at all, its a RGB source of illumination. When you back off to a normal distance the eye combines the red, green and light and is fooled into seeing the whole color spectrum. Most color file formats used on computers, store the individual color data in exactly this way. For each point of light or pixel in an image a 24 bit binary number is stored describing the exact amount of red, green and blue making up the pixel.

Additive Color

This representation of color is called the additive color system. It explains how we see objects that emit there own light. This system states that all perceivable color hues can be created by mixing different amounts of red, green and blue light. Equal amounts of red, green and blue give the sensation of white. The absence of red green and blue gives the sensation of black.

Subtractive Color

Objects which are seen because they reflect light from another illuminant source are explained by the subtractive color system. Color prints fall in this category. The color perceived by the eye while looking at a color print depends on all three factors discussed above — the spectral power distribution of the light source, the spectral reflectance of the object and the spectral sensitivity of the eye.

In a color print, you control the spectral sensitivity of the paper at a given point when you adjust the color balance while looking at the image in Photoshop. The light source the print is viewed under is often out of your control and can be a problem. Certain pigment based inks appear to be identical under light sources of one type, say 2800K tungsten filament sources. The same inks viewed under a different light source, say 6500K daylight appear very different. This phenomena is called metamerism and is a problem for Epson 2000P owners.

When taking a photo, the spectral power distribution of the illuminant is even a bigger problem. Standard color films are either balanced for daylight or a tungsten light source. Anything in between, will require color adjustment in the digital darkroom for accurate color.

It is quite possible the artistic effects created by color shifts are highly desirable. Not many of us would want to trade the warm hues of sunset or sunrise for an accurate set of whites! Once we understand the nature of color, it is possible to control it. There are many color tools in Photoshop that allow you to do this, but that is the topic of yet another tutorial.

http://www.luminous-landscape.com/tutorials/color_and_vision.shtml

Colour Management

Introduction to Colour Management

Profiling Your Monitor

Monitors need to be profiled to give a universal look to any image, so that your image looks the same on any monitor anywhere in the world.

When you purchase a monitor, a good tip is to always search reviews for information on calibration tests that have had good results.

Recommended monitors:

* Apple Cinema Display

* LaCie 321

* Eizo ColourEdge - these are top of the range and expensive but included to give you some idea.

Laptops in general do not calibrate well. A Macbook is thought to calibrate well but even this is not as good as a desktop monitor due to being a laptop with a variable viewing angle between the user and the monitor.

Use a solid calibration device such as a puck or a spyder. Basically they read colour swatches off the monitor and create a custom monitor profile.