You’ve gone out, camera in hand, and taken your pictures, but now where do they actually go? When you are taking a photograph, what is essentially happening is that the camera is capturing data, which creates a digital image. This image is what resides on the memory card of your camera, but the important questions that arise post the photography sessions are - What is the highest quality you can save the picture as? What file saves most memory or takes up the least amount of memory? What is the appropriate way to save images using image extensions? What is the file format - the three letter suffix appended to the end of the file name. When choosing a format for your image, you should be conscious of picture file types that is both the image’s quality and the file size.
Choosing the right file format is important, and can be critical for the level of quality, and also for the level of post-processing you intend to do on it. Digital images exist as files on a computer and there are a variety of different image file types or formats that are used for specific purposes and only a small number of them can be used on the web. Basically, the multiple image file formats that are made available to you differ in how much actual photographic information you wish to “store” within each image file, and how much is discarded. This is the basic nature of compression – the elimination of potentially extraneous information.
- Introduction to Picture File Types
- Understanding Raster Image Files and Vector Image Files
- Different Picture File Types
- RASTER IMAGES FILE TYPES
- VECTOR IMAGES FILE TYPES:
- Lossy vs. Lossless Image Format
- High Resolution vs Low Resolution
Introduction to Picture File Types
In this digital world where everything is shifting to the cloud, it is important and essential that shutterbugs understand the picture file types. It is actually a systematic way of storing all the digital photos that are clicked. And it is important that these image file format store the photos accurately such that the images are flawless and perfect to the eye. So let's dive into the various formats and which one to pick for your photo.
But before that check this:
What happens if you use the wrong type of picture file type format?
Many editing programs will allow you to save the image in various file types, however, if you choose the wrong type of format you could be looking at one or all of the following happening:
- Loss in the quality of the image in the form of blurring or pixilation.
- An unnecessarily large file which takes up unnecessary space.
- The file format might be supported, in which case the image will not display.
- In case of an overly sized file, the image will take too long to load.
So to understand these formats much better, let’s break it down and dive into the basics of each file type.
Most picture file type can be easily divided into two general categories—raster files and vector files—with each category having its own particular uses. A point to be noted though that this division isn’t fixated and most formats could contain elements of both types.
Understanding Raster Image Files and Vector Image Files
They are made up of a set grid of dots, which are known as pixels. Each pixel is assigned a colour. Raster images are resolution dependent, which means they exist at one size. In the process of transforming a raster image, the pixels themselves stretch out, which is what causes the ‘pixelated’ or a blurry image. Mostly, the resulting images aren’t all that great. Every picture that you see online and in print is a raster image file.
These kind of formats are customarily used for digital artwork, web graphics - such as social media content, email graphics, banner advertisements, and photographs.
All raster images can be saved in either of the of two primary colour models: CMYK and RGB.
CMYK is a four-colour printing process that stands for Cyan, Magenta, Yellow and Key (black). These are the four colours of inks that will be combined during the printing process.
RGB is a light-based colour model that stands for Red, Green and Blue, the three primary colours of light which will combine to produce other colours.
These are kind of like mathematical equations at a large scale, wherein each dot, line and shape is represented by its very own equation. Each ‘equation’ can be assigned with its own stroke, thickness and colour to convert the shape into art. Vector images are resolution independent. In the process of shrinking or enlarging a vector image, the shape will increase in size, however, there will not be a loss of detailing, or pixilation. Since the image will go through an identical render there will be no such thing as a Lossy or a lossless vector image type. This type of format is generally used for digital illustrations and typesetting, icons and logos.
Different Picture File Types
We will be discussing the different kind of file types categorized as per Raster Images and Vector Images.
RASTER IMAGES FILE TYPES
JPG (or JPEG) stands for Joint Photographic Experts Group. This format is a standard developed in the 1980s to handle colour digital images. It is a raster image that is most commonly used for photographs on the web, since it works on the fusing of colour. It belongs to the Lossy format category, wherein it reduces the size of the image by blending dispensable image pixels. Once compressed, the image will have blurriness around the edges of the objects in the photograph.
The best use of JPEG format- For rectangle or square photographs on your website. On the web, what you want is for your image files to be as small as possible to enable quick loading, but they should also be crisp and not pixilated. This kind of an image file cannot have a transparent background, and therefore, will always spot a rectangular or square shape with a solid background.
What you will notice with most cameras is that they show JPG image quality setting like low, fine and superfine. Low means high compression, fine means a moderate compression and superfine means low compression.
However, do not confuse this with the image sizes of small, medium and large which actually point towards the pixel dimensions of an image. While using photo editing programs, the compression is denoted in percentages where 0% means maximum compression and 100% would mean no compression. You will be able to notice visual distortions once you reach 50%. Once an image is compressed in JPG format there is no way to ‘un-compress’ it, that is return it to its original quality, which is why, it’s advisable that your original photograph be taken with the least compression as possible.
What does JPG quality losses mean? When using a JPG file as your editing original, each ‘save as’ will cause a degradation even if the JPG compression is set to the highest quality. However, note that you can copy a JPG file with the computer’s copy option multiple times without losing out on quality, it’s only the re-saving of JPG file from a photo editing program after editing or cropping which will cause the degrade of the quality. Clear your confusion on which to pick JPG or RAW and get the perfect photos
- Small image size
- Creates a very good photographic reproduction
- The best format for posting to the web
- Compatible with every image editor and viewer
- Lossy format
- Once compressed it is difficult to recover information
- Photo degradation after editing on save even when at highest quality setting
- JPEG/JPG is considered as the best quality image format despite all the cons taken into consideration and is one of the most popularly used image type format.
PNG stands for Portable Network Graphics and is another type of raster image. For a common universal understanding, the main difference to comprehend between a PNG and a JPG is that a PNG can have a transparent background and is generally larger and higher quality, which is what makes a PNG perfect for logo files for websites, since they can be easily placed over a coloured background.
The size of a PNG image file is bigger than JPEG's but is smaller than BMP's. PNG's compression is among the best available among lossless image formats.
The best use of PNG format –
- Web graphics which require transparency
- Logos, Icons and other images where a transparent background is preferred
- Colour heavy and complex photographs and graphics
- Images that require re-editing and re-exporting
- Pretty good compression ratio, even though not as good a JPEG
- Supports transparency and semi transparency
- The resulted files are not the smallest possible.
- Simplistic program may not support this format.
A GIF is a Lossless raster format image type, which stands for Graphics Interchange Format. This image file extension is created from up to 256 colours from the RBG colour-space. The size of the file will be smaller, if the colours and shades contained in an image are fewer, which is why this type of image file is ideal in the case of images which use only few solid colours and don’t have any gradients or natural shades. A GIF format should not be used for a photograph.
Why? Well, typically GIF files formats supports transparent backgrounds is limited to 256 colors available from the colour palette and there is no way to mix these colours to form new colours. While the number might seem on the higher side of options to choose from, what you must remember is that complex images contain multiple tones, and the colour range tends to get lost during the GIF conversion process. While this can be a limitation for images with wide colour variations, this acts as a benefit in keeping the size of the file small, which then makes it ideal even for the slowest of internet speeds.
While it was replaced by PNG owing to the fear of patent issues, this format is widely used in animation as it’s the only format that supports animation which is widely supported by browsers.
The best use of GIF format -
- Small icons
- Simple animations
- Graphics with low pixel-to-pixel variation, with lots of flat colours such as logos and flags
A TIF (or TIFF) is another lossless raster file, which stands for Tagged Image File Format. This picture file type does not bear the brunt of loss in quality (as long as you don't use JPEG compression within the TIF), and hence is primarily used for in photography and desktop publishing. This type of image file is results in very large image sizes. It also has the option of being compressed, using either a LZW or ZIP, which will shrink it with no loss of data. Even compressed though, a TIF file will be much larger in computer file size than a JPG equivalent.
Since it was an early standard on the mac, TIF is quite a favourite when it comes to graphic designers, considering it’s a lossless format and contains more photo information than a JPEG image type. On the web, because of load time, you generally want to use smaller images such as JPG or PNG.
The best use of TIF format - Images and photographs for high quality print.
- A lossless format, hence all image information is retained
- It is a large file size even post compressing
- It has multiple ‘standards’ which means not all programs can read all TIF files
- Not web browser compatible.
This is a lossless image format which is offered by some digital cameras. The JPEG image which is produced by a camera is an image processed by the camera’s software wherein variables like white balance, saturation, contrast and sharpness are registered to the digital image based on the camera’s settings. RAW, on the other hand, is the direct unprocessed image as seen by the camera’s sensor. This image will allow the post-image processing using any of the camera parameters.
This type of image format is naturally a preference of professional photographers for their image “negatives” or originals as it allows the most amounts of flexibility in the post-processing stage.
The downside to this format is that the format is currently proprietary to the particular camera manufacturer which doesn’t make it ideal for good long term archival standard. What you should do is convert your RAWs to TIFs for archival storage. While there is development being done to try and standardize the RAW format, this is an unlikely shot since newer features constantly being added to digital cameras end up being part of their RAW data, and it’s obvious to note that this keeps changing as new innovations are constantly introduced.
- Lossless format allows for full post processing of all in-camera variables
- Due to the proprietary camera manufacturer format of multiple standards, not all softwares are compatible to view RAW files
- The image type files are large in size
- Not web browser compatible
Bitmap Image is a lossless file format, which was invented by Microsoft, as an initial use for the Windows platform but is now recognized by programs on Macs as well. BMP image types are large file sizes as the colour data is saved in each individual pixel in the image without any compression. Because of this, a high quality digital file is created which is great to use in print, but is not ideal for web usage.
Can be used for printing as images are saved in high quality format
Due to the large file size, a lot of storage is required
VECTOR IMAGES FILE TYPES:
An EPS image format is a vector file which stands for Encapsulated Post Script. This type of format can be of a graphic, text or illustration. Typically, an EPS file includes a single design element that can be used in a larger design. Since it is vector it can easily be resized to any size it needs to be. The good thing about EPS file is that you can easily reopen and work on it. While primarily a vector format, an EPS file can include both vector and raster image data.
Best use of the EPS format - Graphics logo files and print designs.
- Scalable to any size
- Lossless type format
- Compatibility for vector graphics
- Ideal for printing/output
- May lose control of advanced vector editing features
An AI file is a proprietary vector image format that stands for Adobe Illustrator. As understood by the name, this type can be created with Adobe Illustrator. Though AI files are primarily of a vector-based format, they can also include embedded or linked raster images. These types of files can be exported to both PDF and EPS files to create ease of reviewing and printing, and to also JPEG, PNG, GIF, TIFF and PSD in case of web usage and further editing.
Best use of AI format - Creating logos, graphics, illustrations, and print layouts
PDF stands for Portable Document Format and is an image format which is used to display documents and graphics correctly, devoid of the effect of the kind of device, application, operating system or web browser.
While at its core, PDF files have a incredible vector graphics, but it can also display everything from raster graphics to spreadsheets. Since it’s a near ubiquitous standard, you will notice that PDF files are often the file format that are most requested by printers in order to send a final design into production.
- Lossless type format
- Protects intellectual property
- Maintains printed format
- Longer browser loading times
- Non-editable content
- Not great for complex graphics printing
- Not really useful as a graphic image
Lossy vs. Lossless Image Format
The compression of a file can be attained in basically two ways: Lossless and Lossy.
A lossless image format will capture all of the data of the original file, hence being self-explanatory of the term ‘Lossless’. While the image has undergone compression, it will still be able to reconstruct the image to its original state. Every Raster image file either be a Lossless or a Lossy, depending on how the format handles your image data.
A lossy image format will take an approximate of what the original image looks like. For instance, a Lossy image file will reduce the amount of colours in the image or analyse the image for any unnecessary data. These kinds of clever technical stratagem will automatically reduce the file size, although causing a possible reduction in the quality of the image.
Normally, Lossy image files are much smaller in size than Lossless image files, which makes them ideal to be used online where the file size and download speed are vital elements.
High Resolution vs Low Resolution
In order to determine if your images are a suitable resolution for a particular purpose, what you need to check is their pixel density. There are two units of measurement, which are DPI -Dots per Inch or PDI - Pixels per Inch which refers to the number of pixels in one inch of the image.
These measurements become of utmost importance when you attempt to use raster images in specific places, such as on the web or in print publications.
The web, for example, displays 72dpi (72 dots or pixels per inch) which is of a relatively low pixel density. Therefore, images which have a low DPI like 72dpi look sharp and crisp on the web. However, this same low DPI image will not be suitable say in the case of printing on a brochure or packaging, since in order to correctly print an image, it should at least be of a 300dpi, a comparatively much higher pixel density than the web display requires.
If you resize a low DPI image which you have pulled from the web, so as to fit the dimensions of your print project, the image simply won’t do because of the number of finite pixels available will only get bigger and begin to distort.
So instead of just asking yourself: Which picture file types to pick, try and base your decision upon your photographic wants and needs.
It’s way more than just considering file size; it’s also about anticipating how much post processing work that you might have to do get the best image possible. While JPEG is one of the most widely used file formats, which allows you to save an image not only as a small file and but also in high quality, TIFF and RAW formats maintain exceptionally good picture quality but with a larger size, preferred by most of the professional photographers out there. Using the right type of format for the right job means your image will be picture perfect and just how you intended.
The simple mistake of using the wrong format could mean a bad print or a poor web image, a giant download or a missing graphic in an email. Hopefully we have been able to shed light and provide you with a better sense of what common digital photo file types actually are.