Colour Modes
The first part of this unit is about colour theory, colour mode and colour management. The most widely used colour model is RGB (which stands for Red Green Blue), this is used by combining the primary colours red, green and blue light together in various ways to create an almost endless amount of colour. The RGB model is for sensing, representation and display of images in electronic systems, such as TV and computers, though it has been used in photography also. Before RGB was used in electronic systems, there was already a solid theory behind the whole model as it was originated in how humans see colours. RGB is a colour model that is "device dependant" which means different electronic devices detect different values of RGB as their responses to the individual levels of Red Green and Blue are all different depending on manufacturer (also the device can detect more or less values over time with the age of the device). So RGB does not define a specific level and value of colour in every device without colour management.
The most well known devices that use RGB as input for colour are colour TV's, video cameras, image scanners and digital cameras. Devices most well known for output of RGB are LCD and Plasma TV's, computers, mobile phone display screens, video projectors, LED displays. Despite what you may think though, colour printers do not use the RGB mode, they tend to use the CMYK colour model which is most commonly used within the printing process, which i will explain next.
The CMYK colour model uses the RGB model which is typically in computer screens for example and combines the three primary colours to create its own, as RGB can only be created using natural or produced light (like in computer screens) so there had to be a different colour model to replace RGB for the printers. The CMYK stands for Cyan (green and blue creates it), Magenta (red and blue creates it), and Yellow (red and green creates it) as you can see CMYK is basically all of the RGB colours mixed to make slightly different colours that are not the primary colours created from natural/produced light (Cyan, Magenta and Yellow are all subtractive primaries). Black is the K in CMYK which stands for 'Key' as black cannot be made by RGB as it just created a dark brown, which is not required.When CMYK is used in the printing process, the four colours are combined on paper using small dots which combine the different colours together until the final image is created.
Graphic designers have a problem with this process with the colour models RGB and CMYK as they see their work on the computer screen in RGB, and once their final image is used and is printed, they will see the image on the paper in CMYK colour which gives the image an almost total different look. Programs such as Adobe Photoshop can convert files into RGB/CMYK however you see fit. To give your clients and yourself a good idea of what your images will look like in different colour modes, you should make good practice in creating different swatches to provide yourself and your clients with a good idea of what everything looks like. Printers also give you the choice of creating a proof print, which is an example of a printed piece before the print is actually done which will be in the CMYK colour mode.
Image Resolution
Image resolution is basically the total amount of pixels in an image or the width and height of an image as well as the amount of pixels in the image. Every computer screen has a set resolution that it can use, usually depending on the size of the screen generally. If you have a 17" monitor, you are most likely to have the monitor set to 800x600 pixels etc. Resolutions can be changed but normally these are the optimum settings for the screen size. If a monitor is set to 1024x768 and you open up an image that is 640x480, it will not fill up your screen, but if you open up a image that is 2048x1536 you will either find that you will have to scroll to the right and also down, or the image will be decreased in size to at least fit your screen. A computer monitor has a limited amount of ppi (pixels per inch) so if you are going to display an image just on a monitor you should drop the quality to 72 ppi to save file space. If you are going to put an image on a webpage or email, then you should first adjust the image to the correct size so the image is just the right size for what you want, and if needed compress the image to save space.
Image quality can be manipulated and compressed. certain file types such as BMP or TIF files don't compress the image, so they keep their quality. File types such as JPG reduce the file size, but also reducing the quality depending on the amount of compression you want before saving the image. JPG compression analyses images in blocks of 8x8 pixels in size and reduces the detail within each block. At higher compression rations the pattern becomes more visible and there may be a large loss of detail, this also happens when you try to make the JPG image larger than its default size, you start to see lots of blocks as the compression of the image has decreased the quality depending on how much detail is in the image, for example if there is just a picture of a blue to white gradient, the image will have to be compressed a considerable amount more than, say, a picture of a car which will lose detail in very low amount of compression and start to look increasingly pixelated.
Metadata
Metadata is data providing information about one or more aspects of data such as:
- Means of data
- Purpose of data
- Time and date of creation
- Creator of data
- Location of data (on a network)
- Standards
- Titles of files such as music
metadata contains data for the size, colour depth, resolution, date of images along with other data also. A text documents metadata contains information about how long the document is, the author, date of document, and a short summary of the document. Metadata is used in photographs for digital photo files to identify who owns it and also the copyright information and contact information, what camera created the file and also the exposure information and descriptive information such as keywords about the photo, making the file searchable on the computer and/or the internet. Metadata can also be used in videos for information about contents like transcripts of conversations and descriptions of scenes. Web pages also use metadata but a different form of data called meta tags. these tags are descriptions of the pages content. most search engines use this data when adding pages to their search index. To create metadata you can manually create it or it can be automatically be done for you.
Copyright
Copyright is a legal concept which is used all around the world to give the creators of their own work the exclusive rights to claim all credit for their work so that no one can legally recreate their work legally without the original creator's permission. To fully secure your work, you should register whatever you want copyrighted so that you have solid legal evidence on whoever has allegedly stole some of your copyrighted work. Copyright also applies to photography. Generally, whoever has took a picture has the copyrighting rights, but if the photographer works for a company that has specifically wanted the employee to take those pictures, the company owns all rights to that picture. This applies to anything else that is done under a companies name, as they have told the employee to take that picture.
If you have a image that you have copyrighted, you should mark it with copyright to tell them that they cannot use the image without permission by you, and you should also insert your e-mail, or any contact details and who you are, as there are many problems with people who have found a copyrighted image, but cannot get hold of the owner to see if they can get permission to use the image.
If you want to use someone elses work that you have seen and like, you should contact the owner if there is any way of contacting them, such as a mark on the image that has their contact details on it, if you cannot find any contact details, you cannot use the image as if you do, you will be breaking the law. If you do get through to the owner you must be prepared to pay a fee as there are very few people who would want to let their work go for free and you must also remember that the owner is not legally obliged to let you use their work so you should also be prepared for them to tell you that you cannot use it.
If you have a image that you have copyrighted, you should mark it with copyright to tell them that they cannot use the image without permission by you, and you should also insert your e-mail, or any contact details and who you are, as there are many problems with people who have found a copyrighted image, but cannot get hold of the owner to see if they can get permission to use the image.
If you want to use someone elses work that you have seen and like, you should contact the owner if there is any way of contacting them, such as a mark on the image that has their contact details on it, if you cannot find any contact details, you cannot use the image as if you do, you will be breaking the law. If you do get through to the owner you must be prepared to pay a fee as there are very few people who would want to let their work go for free and you must also remember that the owner is not legally obliged to let you use their work so you should also be prepared for them to tell you that you cannot use it.
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