Understand key issues relating to undertaking colour management procedures
1.1 - 1.2
Explain the principles of colour theory, colour mode and colour profiles
There are three basic categories of colour theory:
- The colour wheel
- The colour harmony
- The context of how colours are used
The colour wheel is a circle that is based of red, yellow and blue which are the primary colours. In traditional colour theory these colours are the 3 pigment colours that can not be mixed or formed by any other combination of colours. All other colours are obtained from these 3 hues. Secondary colours are green, orange and purple which are the colours that are formed when mixing the primary colours. Tertiary colours which are yellow-orange, red-orange, red-purple, blue-purple, blue-green and yellow-green. These are the colours that are formed when mixing a primary colour and a secondary colour.
The colour circle can be divided into warm and cool colours. Warm colours are vivid and cool colours create a calm and soothing feel.
White, grey and black are considered to be neutral. If a colour is made lighter by adding white it is called a tint. If black is added to make it darker it is called a shade and if grey is added it is called a tone.
Colour Harmony
From a visual point harmony is something that pleases the eye. It engages the viewer and creates a sense of order and balance. The human brain will reject under-stimulating information, if the image is chaotic then the viewer won't want to look at it. Colour harmony delivers visual interest and is a dynamic equilibrium.
There are many theories for harmonies but the ones described below are basic colour chords that are based on the colour wheel.
Complementary colour scheme
Colours that are opposite each other on the colour wheel. The high contrast of complementary colours creates a vibrant look, they can be tricky to use in large amounts but are really useful when you are wanting something to stand out.
Analogous colour scheme
Colours that are next to each other on the colour wheel. They match well and create comfortable designs. They are mostly found in nature and they are appealing to the eye. You have to have enough contrast when choosing an analogous colour scheme. One colour needs to dominate, the second support and the third distinct.
Tetradic colour scheme
The rectangle or tetradic colour scheme uses four colours into two complementary pairs of colours. This colour scheme is rich and offers many possibilities of variation. It works well if one colour is the most dominant.
Other colour schemes that are considered harmonic include:
- Triadic colour scheme - three colours evenly spaced around the colour wheel. Considered vibrant even when using pale or unsaturated hues. The colours need to be balanced with one colour dominant.
- Split-complementary colour scheme - Has strong visual contrast but has less tension.
- Square colour scheme - All four colours spaced evenly around the colour circle. Works best if you let one colour be dominant.
A colour model is a method to translate the light captured in an image into digital form that the computer and other devices can understand. Each colour models breaks the light into one or more channels and then it uses an intensity level of each channel for each pixel in the image.
The RGB colour mode refers to Red,Green and Blue is an additive colour model in which these colours are added together to produce a broad array of colours. A colour profile is a numerical model of a colour space. Operating systems and programmes need access to a profile that describes the meaning of the colour values to interpret the colour correctly. There are two types of colour profiles: Matrix-based profiles use mathematical formulas to describe the three-dimensional colour space. Table-based profiles uses a large table of sample points. These profiles are more customisable and more useful when translating colour information from one space to another.
Be able to manage and calibrate hardware to maintain colour accuracy
2.1-2.8
Each make of camera, printer or monitor generates colour differently. Printers and publications use CMYK which are the primary colours in ink. Mixing the 3 colours RGB, used by cameras and scanners, it produces white. With CMYK colour when the colours are mixed it creates black. Digital devices such as displays and printers have their own characteristics and will not produce colours in the same way. ICC profiles provide a way of overcoming differences in devices by standardising the colours produced by each device. Some cameras have a selection in their settings that allows you to use standard RGB but sometimes you have to calibrate cameras to get the same colours and tones.
If you work for a photography company they will sometimes want all of the employees to use the same cameras so that all the images are the same. This means that if the company wants reds to appear more then all the cameras will have the same effect and colours.
Monitor colour calibration makes sure that the colours your computer or laptop shows are accurate as possible. It allows you to get the best possible results from photographs. The first step is to view the screen in the correct light as this can make a difference to the colours shown on screen. You can then adjust your monitor and set the temperature to 6500k and set up your printer by clicking on the printer manages colour and then select the paper. It is easier if you use the same brand of printer and paper.
Using a colorimeter is expensive to buy but it tunes the monitor and printer by checking the ambient light and the printed colour.
A colour checker rendition chart is also a colour calibration that consists of an arrangement of 24 squares of painted samples. Using one of these can get you a lot closer to the actual colours of the photograph.
A grey scale chart shows gradiations of neutral grey from pure black to pure white.
The features and benefits of colour separation and grey scale charts are to identify colour separation negatives and positives for colour reproduction process. You can also identify, measure and control captured and reproduced images to compensate for changing conditions.
Some screens use a built-in ambient light sensor which makes automatic brightness adjustments based on the current lighting conditions. You can calibrate them so that they don't effect misinterpretation from the human eye.
As shown in the video the screen calibration can be changed in the computer settings under Display Colour Calibration. It explains how to adjust gamma which is the relationship between red, green and blue. The colour values are sent to the display. Also shown in the video you can alter the visibility of the gamma dots in the circles. It also allows you to alter the darkness and lightness.
I have taken a few screenshots below which shows you how to get onto colour management from the desktop.
Window > System32 > Spool > Drivers > Color
3.1-4.3
A printer profile is a file that determines how colours are to be printed for a specific printer and paper. With printer profile aware image editing or printing software, it transforms the image from colour space to the printer and paper's colour space.
To get the right colour on the computer there has to be colour information. Profiles can be created and attached to files in a few different ways.
When a JPEG file is created in a digital camera a profile is usually attached to it. Cameras are Standard RGB and Adobe RGB.
When a RAW file is created it has no profile. The profile is applied to the file when it is opened by a raw converted into a rendered file type such as JPEG or TIFF.
The file formats were covered in Unit 41 in 1.3. The best format to use for a master copy is PNG as it is easy to be able to open. If the master copy was saved in RAW then you might not be able to open it in the future.
In Photoshop if you go to View > Proof Setup it allows you to check how your image will look on other colour spaces and devices that are different from the space of the currently used colour profile of the image.
Soft proofing is a useful tool as it allows you to see on screen how your photograph will look when it's printed. This allows you to spot any problems before you print.
You can select an ICC profile from the drop down list on Device to Simulate. As I haven't created any profiles Photoshop has a range of profiles that are already downloaded.
If your computer is connected it will also automatically download profiles.
I selected a few profiles at random just to see the difference between them.
I selected ColorMatch RGB. If you are going to be using the profile a lot it is useful to save it.
Gamut is a word applied to digital devices. The gamut of a digital device is the entire range of colours and tones it can display, capture and print. View > Gamut Warning shows any unreproducible colours by the device being simulated will turn to grey.
When selecting ColorMatch RGB there is a large area of grey so this wouldn't be the profile to chose. The grey areas show us the colours that the printer won't be able to print because some of the colours are too saturated.
When selecting Panavision Genesis Tungsten Log by Adobe there was no grey that appeared when selecting Gamut Warning so this would be a good profile to print in.
5.1-5.3
Health and safety procedures must be put in place whilst using computers and electrical equipment. Ensuring that there are no liquids near that could spill and damage the equipment, and making sure that all equipment is neatly put together to prevent incidents happening. It is important that you are aware and have reviewed the hazards, risks, fire evacuation routes and first aid facilities. In our work building the first aid facilities are in the main administration office and the fire evacuation routes are the main door, the back door and the side door which leads to the school playground. A risk assessment should be carried out pointing out the areas and hazards. Control measures should be put into place to prevent these hazards from happening. I carried out a risk assessment in unit 6.
Minimising risks are important in the workplace, taking regular breaks from computer screens and from electrical equipment is one way to reduce this. PAT testing is carried out every year on the electrical equipment and is also tested on new equipment. In my workplace everything has to be PAT tested so that it is safe to use. This could be considered as a way of minimising risks.
The software I use to undertake adjustment of photos is Photoshop. We don't have access to Photoshop due to school policies but where the old building was located the school purchased the adobe package.
There is procedures that I need follow at work. As I use a computer and electrical equipment every day I need to ensure that all cables are neatly tied and none are damaged. I also need to make sure that I take regular breaks from the computer screen. Other procedures that I need to know are where the first aid facilities and fire evacuation procedures.
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