Image types: RAW files in a nutshell

If you read last week’s blog post, you’ll know that I’m writing a series of posts to give an overview of several major file types, and the benefits and drawbacks of each. Last week I did an overview of JPG files, this week I’ll discuss RAW files.

Overview of RAW files

RAW (.CR2, .NEF, etc.)

Many high-end consumer digital cameras and most professional SLR’s (single lens reflex – attachable lenses & camera body) offer an image file format known as camera RAW. The file extension is brand specific – .CR2 for Canon, .NEF for Nikon and many others.

Unlike JPG files, camera RAW files are not compressed when they’re saved, so every bit of data associated with an image is preserved when you make changes.

One of the benefits of processing with RAW files is that settings can be adjusted separately from the image data. When you use automatic shooting modes or the camera’s custom settings, the effects of these settings are saved onto the device’s memory card. With camera RAW, these settings are not permanent, and can be adjusted later.

Consider the white-balance setting of your camera. If you set it for incandescent lighting indoors and walk outside without changing it, what will happen? The outdoor shots will be intensely blue. If you are shooting in JPEG mode, what you shot is what you get. If you are shooting in RAW, you can adjust those settings after the fact.

Cameras that allow RAW shooting come with RAW editing software suites to install on your computer, or you can use professional image editing software like Photoshop. Software with RAW editing capabilities gives you many of the same controls featured on your camera, plus many more. When you open an image in a RAW editor and start making adjustments, they are saved as a “recipe”. You cannot save over a RAW file. If you adjust the sharpness, crop the image, increase contrast and alter the exposure, these adjustments are saved in the recipe file, but the RAW file remains intact and unchanged. This same recipe file can be applied to other RAW files for very quick editing of large amounts of photos.

It’s important to understand that a recipe file and a RAW file are two different kinds of files.   A recipe file is simply a list of instructions associated with a particular RAW file. Once you’ve created a recipe file, it can only be read by the image editing software that created it. Remember, you cannot save over a RAW file. For this reason, RAW files are considered digital negatives.

The last thing to note after a long afternoon of editing your RAW images is that you won’t be able to just hand them over as finished products on a disk. You would be giving your client a set of RAW files and recipes they’re unable to open or use. Instead, you’ll want to process the recipes and RAW files into JEPGs or TIFFs before handing them off.