Understanding the basics of photography and how digital images are stored is important if you want to be able to produce great images. Using tools such as Photoshop for editing can greatly enhance an image, but how it’s stored on your camera in the first place can make a big difference to what you can do to it later on.
Our Photoshop course not only tells you how to edit images, but gives you the technical understanding behind different types of image files, how colours are made up and how to understand image size and resolution. We also offer Advanced Photoshop training for those who want to take their technical knowledge further.
To get you started, here’s some information about Raw files, and when you might want to store images on your camera as Raw instead of as JPEGs.
What is a Raw File?
A Raw file is simply an exact recording of the data that is produced by the sensors of a camera. Like negatives, they need processing to be turned into an actual image file. You need specialist software like Photoshop to view them, and as soon as you make any changes to a Raw file, it becomes an image file and must be saved as a jpg, png, psd or similar. Images in the form of Raw files can’t have been manipulated, so they can be used as evidence in court.
Raw files are used to capture and store the basic information about a scene. Because of this, they are not subject to any limitations in terms of colour or light intensity. Raw files appear less sharp and more washed out because they are lower in contrast.
With most digital cameras, these Raw files are stored alongside a JPEG thumbnail, so they can be previewed on-device. Similarly, meta-data will be stored with Raw files, such as the data and time and settings used to take the photo.
What is a JPEG?
When you save an image as a JPEG on your camera, the image is compressed so it takes up less memory. With this compression, the levels are reduced significantly, which has an impact on your options for editing later on. JPEGs can be viewed pretty much universally, without the need for specialist software or processors, and you can print JPEG images straight from the camera.
When to use Raw
You can set cameras to store Raw images as default – many professional photographers choose to save Raw images because they then are not limited to specific brightness levels. One disadvantage of this is that, generally, each make of camera has a different way of encoding Raw files, which means the image comes out differently. The good news is that Photoshop has a built-in Raw converter that supports all widely used (and some not-so-widely used) digital cameras on the market.
The Raw image is the highest quality possible – it is exactly what was recorded by the camera and has not been altered in any way. This is great at both ends of the spectrum – purists know that the image is true, and those who want to manipulate the image manually can do so with complete control from scratch. For example, when colour filters are added via a computer, these can be done with more sophistication than would be possible on a camera. The main advantage of Raw images is that the photographer has a 16-bit image to work with in processing, as opposed to the 8-bit levels that JPEGs are limited to.
When to use JPEG
Many cameras can store images in both formats, which is great for those who want to keep their options open. You should definitely store pictures as just JPEG if you need to take a lot of snaps in a short time – cameras take longer to take and process Raw images. Similarly, if your camera’s memory is limited, use JPEG to store more photos.
The image quality from JPEGs is good enough for almost all kind of everyday photographs. They are still large enough to be printed, and the contrast, white balance and saturation applied as a result of storing as JPEG means you may not need to do any post-processing at all.
The main point to remember is that all images begin as a Raw file. The choice that photographers need to make is whether to convert to them to JPEG immediately, with the benefits and disadvantages as above, or whether to wait until the file is on a desktop computer where it can be converted by external software like Photoshop.
Main image thanks to Roland on Flickr.
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