Digital Graphics
There are two main types of digital image formats raster graphic files and vector graphic files. Vector image formats are most effective when being used for defined lines, curves and shapes of charts, logos, web graphics, technical drawings, cartoons and fonts. Due to the increased quality with vector files i feel they re much better to use on blown up images with more pixels which allows the pictures to be used on a wide screen tv, poster or bill boards. This means no matter what size the image is the quality will remain the same which is a major advantage vector has over raster graphic files. Vector files are unique as they are written in there own language which is hard for the raster graphics file to understand thats why its difficult to convert a vector file into a raster file which is called vectorise. Converting a vector file into a raster file is much simpler as raster files are made up of pixels, this process is called rasterise. Which is a big disadvantage of the vector graphics file especially if you have a vector file image and you need to need to convert into into a raster file so you can edit it in a raster format program like photoshop. Vector images are made up of many different elements called vector objects, these can make curves, circles, rectangles or any other shape connected by paths and points. Vector objects are written in mathematical instructions and not pixels it enables the image to be scaleable or transformed without using any quality. The easiest way to best describe how these mathematical instructions are written so vector programmes can transform them into vector images is through basic maths such as plot a line from A to B or draw a circle with a diameter of X. Vector graphic images are used in everyday simple programmes in order to aid people with the most basic tasks such as in programmes like word and power point. Some of the basic functions vector's can perform are drawing lines, arrows and shapes, drawing fonts (which are scaleable) in programmes like word art and drawing simple charts and graphs like bar charts and tally charts in word. Vector files are also used for much more complicated tasks such as creating motion graphics, animations and illustrative drawings in programmes like adobe flash and illustrator. Most vector language is unreadable as they use there own proprietary files to produce the image however there is one file format vector type called scaleable vector graphics (SVG) which is readable as it is text based and written in a language humans and computers can understand. Here is an example of an SVG from the website JISC digital media.
<rect width="120" height="80" fill="rgb(255,51,0)"stroke="rgb(0,0,204)" stroke-width="4" />
Basically what the code is saying is the size of the shape which is a width of 120 pixels and a height of 80 pixels. and the colour of the shape on the rgb scale for the orange is 255 red 51 green and 0 blue which is to be outline by some blue with a width of 4 pixels which is 0 red 0 green and 203 blue on the rgb scale.
The other main file type are Raster Graphic files which are made up of a grid of pixels and dots also commonly called bitmap. This is why when you enlarge Raster files they lose quality as the pixels becomes stretched and out of proportion, which makes the image look all pixelated and of a poor quality. The most common raster file types are GIF and JPEG and they are most commonly used to compress large amounts of data so the pictures can be uploaded to the internet. In comparison Vector files are much better with bigger pictures then Raster files you can see this if you were to zoom into a vector image and raster file as the raster file looks all pixelated and blocky, where the vector file looks clear and the focus is sharp as if you haven't even zoomed into it, this is why Raster files are much better for small prints like, business cards, celebration cards or small prints on badges. With raster files they are made up of a grid of pixels and each pixel represents a individual colour on the picture. Rasters can still look clear as long as they are shown in the right picture ratio, but as soon as the picture ratio changes the picture becomes unclear. Raster files are best used on the internet when sending pictures to people your friends over facebook or in an email as the file size is small (but not smaller then vector) which means you can send multiple pictures at a time also they dont have to be of an amzing quality as they are only going to be for friends to view, plus they will still be of a good quality as people dont really tend to blow up pictures in facebook or in an email. When comparing raster and vector files, raster files are a bigger file size but tend to load quicker where vector files are smaller in file size but tend to load slower. Also raster files are difficult to convert to vector files where vector files convert easily to raster files, raster files also have a grid/matrix structure where vector files have a mathematical or textual description. raster files are used for photography and photo realistic imagery where vector files are used for drawings and diagrams that can be written mathematically. Raster files typically lose quality when they are scaled up where vector files do not lose quality no matter what the size of the picture is. Raster files are also common on the web where vector file types are not usually used on the web. After doing a side by side comparison of all the typical conventions of raster and vector files i have come to the conclusion that no file type is better overall, really it depends on what you want to do with the picture and how you want to change the picture e.g. if you want a picture to send to your friends or to post on the web that doesn't take up to much space and loads quickly which still maintains good quality on a small scale then you would want a raster file type. But if you want an image which could be an animated graphic for a logo on a poster or something but you want it blown up as big as possible so people can read the logo when they see the poster then you would chose to use a vector image file.
The other digital image format which i haven't mentioned yet is Metafiles, a metafile is basically a hybrid as it has a combination of both raster file formats and vector file formats hidden within its data. This gives it an advantage over vector and raster files as it means it doesn't have any trouble reading both file formats and it can be scaled up without loosing quality while still using pixels in the image. So in other words metafiles can store pictures in vector graphics and bitmap formats as well as text. So a metafile could be a vector image but it could contain an object which has a bitmap pattern applied as a fill. So within the image there is still a vector object used but the fill part is made up of bitmap data which is commonly used in a raster file. The most common meta files are WMF (windows metafile), EMF (enhanced metafile), and CGM (computer graphics metafile).
When compressing files there are two main ways it is done redundancy reduction and irrelevance reduction. Redundancy reduction is often used during lossless encoding, the way it works is it looks for patterns and repetitions that can be expressed more efficiently. For example if i had a file where there are 25 values all the same, it makes much more sense to record the information once and tell the program that the next 24 values are all the same, instead of recording each value separately. This particular example is known as run-length encoding (RLE). Irrelevancy reduction is the process of removing or altering information that makes almost no difference to the files content. This deleting of information usually happens prior to the encoding and involves an irreversible ‘lossy' transformation of the content. Some of the information that can be deleted or reduced is things like the video's colour information however this does not matter to much because it can be safely reduced where the human eye can't tell the difference. However the downside to this compression technique is that when large amounts of data is changed or deleted it can damage the quality of the image quite considerably. With irrelevancy compression it is based on human perception so the idea is it deletes the information that is more easily percieved which is the information where if some of it was missing or large amounts of it was the human eye or ear would not notice that some of the information was missing. With lossless compression's they mainly use redundancy reduction and they tend to focus on more effective and efficient ways of encoding data. The big advantage of lossless compression and the most important thing to remember is none of the information is ever lost forever or irretrievable in the compression process. One of the most common lossless compression file formats is the .zip, it can be used to compress multiple text documents when transporting them so when they are zipped up they will become a smaller file size using irrelevancy reduction but then when the file is unzipped the exact same text documents will be reconstructed. The other ways to compress files is through lossy compression which is done through irrelevancy reduction and some redundancy reduction. Lossy compressions transform and simplify the file information in a way that gives it a much larger reductions in file size than lossless compressions. On average a standard lossy compression can cut the file size but about 3/4 or 2/3, in some cases even 1/2 if it is efficient. In some cases lossy compressions can reduce file size down to even 1% of the original file size however anything less that 10% can severely damage the file's content. However the big disadvantage is lossy compression is irreversible and the data that is deemed irrelevant is lost forever. A JPEG is a good example of an everyday used file format that uses lossy compression.
<rect width="120" height="80" fill="rgb(255,51,0)"stroke="rgb(0,0,204)" stroke-width="4" />
Basically what the code is saying is the size of the shape which is a width of 120 pixels and a height of 80 pixels. and the colour of the shape on the rgb scale for the orange is 255 red 51 green and 0 blue which is to be outline by some blue with a width of 4 pixels which is 0 red 0 green and 203 blue on the rgb scale.
The other main file type are Raster Graphic files which are made up of a grid of pixels and dots also commonly called bitmap. This is why when you enlarge Raster files they lose quality as the pixels becomes stretched and out of proportion, which makes the image look all pixelated and of a poor quality. The most common raster file types are GIF and JPEG and they are most commonly used to compress large amounts of data so the pictures can be uploaded to the internet. In comparison Vector files are much better with bigger pictures then Raster files you can see this if you were to zoom into a vector image and raster file as the raster file looks all pixelated and blocky, where the vector file looks clear and the focus is sharp as if you haven't even zoomed into it, this is why Raster files are much better for small prints like, business cards, celebration cards or small prints on badges. With raster files they are made up of a grid of pixels and each pixel represents a individual colour on the picture. Rasters can still look clear as long as they are shown in the right picture ratio, but as soon as the picture ratio changes the picture becomes unclear. Raster files are best used on the internet when sending pictures to people your friends over facebook or in an email as the file size is small (but not smaller then vector) which means you can send multiple pictures at a time also they dont have to be of an amzing quality as they are only going to be for friends to view, plus they will still be of a good quality as people dont really tend to blow up pictures in facebook or in an email. When comparing raster and vector files, raster files are a bigger file size but tend to load quicker where vector files are smaller in file size but tend to load slower. Also raster files are difficult to convert to vector files where vector files convert easily to raster files, raster files also have a grid/matrix structure where vector files have a mathematical or textual description. raster files are used for photography and photo realistic imagery where vector files are used for drawings and diagrams that can be written mathematically. Raster files typically lose quality when they are scaled up where vector files do not lose quality no matter what the size of the picture is. Raster files are also common on the web where vector file types are not usually used on the web. After doing a side by side comparison of all the typical conventions of raster and vector files i have come to the conclusion that no file type is better overall, really it depends on what you want to do with the picture and how you want to change the picture e.g. if you want a picture to send to your friends or to post on the web that doesn't take up to much space and loads quickly which still maintains good quality on a small scale then you would want a raster file type. But if you want an image which could be an animated graphic for a logo on a poster or something but you want it blown up as big as possible so people can read the logo when they see the poster then you would chose to use a vector image file.
The other digital image format which i haven't mentioned yet is Metafiles, a metafile is basically a hybrid as it has a combination of both raster file formats and vector file formats hidden within its data. This gives it an advantage over vector and raster files as it means it doesn't have any trouble reading both file formats and it can be scaled up without loosing quality while still using pixels in the image. So in other words metafiles can store pictures in vector graphics and bitmap formats as well as text. So a metafile could be a vector image but it could contain an object which has a bitmap pattern applied as a fill. So within the image there is still a vector object used but the fill part is made up of bitmap data which is commonly used in a raster file. The most common meta files are WMF (windows metafile), EMF (enhanced metafile), and CGM (computer graphics metafile).
When compressing files there are two main ways it is done redundancy reduction and irrelevance reduction. Redundancy reduction is often used during lossless encoding, the way it works is it looks for patterns and repetitions that can be expressed more efficiently. For example if i had a file where there are 25 values all the same, it makes much more sense to record the information once and tell the program that the next 24 values are all the same, instead of recording each value separately. This particular example is known as run-length encoding (RLE). Irrelevancy reduction is the process of removing or altering information that makes almost no difference to the files content. This deleting of information usually happens prior to the encoding and involves an irreversible ‘lossy' transformation of the content. Some of the information that can be deleted or reduced is things like the video's colour information however this does not matter to much because it can be safely reduced where the human eye can't tell the difference. However the downside to this compression technique is that when large amounts of data is changed or deleted it can damage the quality of the image quite considerably. With irrelevancy compression it is based on human perception so the idea is it deletes the information that is more easily percieved which is the information where if some of it was missing or large amounts of it was the human eye or ear would not notice that some of the information was missing. With lossless compression's they mainly use redundancy reduction and they tend to focus on more effective and efficient ways of encoding data. The big advantage of lossless compression and the most important thing to remember is none of the information is ever lost forever or irretrievable in the compression process. One of the most common lossless compression file formats is the .zip, it can be used to compress multiple text documents when transporting them so when they are zipped up they will become a smaller file size using irrelevancy reduction but then when the file is unzipped the exact same text documents will be reconstructed. The other ways to compress files is through lossy compression which is done through irrelevancy reduction and some redundancy reduction. Lossy compressions transform and simplify the file information in a way that gives it a much larger reductions in file size than lossless compressions. On average a standard lossy compression can cut the file size but about 3/4 or 2/3, in some cases even 1/2 if it is efficient. In some cases lossy compressions can reduce file size down to even 1% of the original file size however anything less that 10% can severely damage the file's content. However the big disadvantage is lossy compression is irreversible and the data that is deemed irrelevant is lost forever. A JPEG is a good example of an everyday used file format that uses lossy compression.
Photoshop First Edited Photo
When editing this photo i used a range of photoshop tools to demonstrate a range of skills that can be used in the raster based programme. When editing this photo the main tools i used was the magic wand to select the areas to edit and the text tool to add text to the image. Once i had selected the area i wanted to edit the main option i chose to use was image and then adjustments, from there i went onto pick a range of options to complete the edit. To make the picture more interesting i chose to edit different sections of each letter so one letter had like 4 or even 5 different effects on it, which made the letter multiple different colours by the time i finished the final edit. I first started off by changing the hue and saturation of the image which i did for the head, then with the body i changed the hue and saturation but I also added in some highlights and shadow to create the green outline. With the first 2 letters i edited the hue and saturation but then i decided to get more experimental so on some of the other letters i edited as well as changing the hue and saturation i changed the brightness and contrast which is how i got this red and orangey colour. With some of the much brighter colours e.g. the white pinkey colour and the bright yellow i edited that by changing the colour with a bit of hue and satiation but then i dramatically upped the exposure until some of the colours were really over exposed. I added the text to give the picture my own personal touch as this picture has a specific relevance to me.