Tutorials:RAW : Starting to process RAW files

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This page is a chapter in the book Post Processing Articles.
Starting out with RAW

So, you are shooting in JPG and might be interested in changing to shoot in RAW, this tutorial is written to give you a bit of an overview of RAW processing.

A few things about RAW

When you take a photo, the sensor transmits data to the camera about what each pixel-site “saw”. This data is the RAW information. A RAW file is the equivalent of a negative, in film terms.

RAW files need to be opened in software that can read the RAW data and present it on your monitor. There are numerous RAW programs, often called Raw Converters, available. Which you choose is entirely up to you, but they all allow you to do similar things.

RAW files are much bigger than JPG files, so you might find you will want larger memory cards, if you decide to shoot in RAW all the time.

Some of the advantages of RAW. Edits to a RAW file in your Conversion software are "non-destructive", they can be un-done, changed, redone without any degradation to your RAW file. White balance can be changed, Exposure can be changed, along with many other advantages. For a good description of RAW, see: http://en.wikipedia.org/wiki/RAW_image_format

Things you need to do

- To shoot in RAW, you will need to use your camera’s menu system and select RAW
- You will need to have some RAW converter software installed on your computer
- You will need to have uploaded the RAW files from your camera to your computer

This tutorial will use Adobe Camera Raw (ACR) although you can choose other RAW converter software and the basic instructions will be the same - you will just have to interpret them for your software.

There are several ways to open a RAW file into ACR, one of the easiest is to use photoshop and File > Open and locate your raw file on your hard disk and double-click it. Photoshop will automatically open ACR when it detects a RAW file.

On the above screen capture, there are a few things to look at.
- Above top left of the photo are several tools, these include a crop tool, a straighten tool and more. These are worthwhile experimenting with in your own time.
- Down the right side is a histogram, some more tools and sliders. (to understand how a histogram works, which is worthwhile to learn as you can use the histogram on your camera's LCD to check exposure etc at the time of shooting, read this)

We are going to look at some of those sliders.

White balance can be altered by clicking on the drop down menu and choosing another setting, or you can move the sliders for temperature and tint. You can also type a Kelvin temperature into the box next to the temperature slider.

Exposure, you can adjust the exposure of your RAW file. Note how on the histogram for this photo, there is a lot of bunching on the left hand side (the left hand side is the shadows of your photo, the right hand is the highlights). You can adjust the exposure slider to compensate and correct this photo and produce a better histogram.

Recovery, allows you to recover some of the highlight area, and reduce their brightness. Note that blown highlights are very difficult to recover effectively and its better to get that right in camera, rather than try to repair a blown out sky etc.

Fill light, works on the shadow areas, to bring more brightness to the darker areas of your photo. Over use of this can create noise in the photo.

Blacks, gives the shadow areas (blacks) a rich deep black. Use carefully.

Brightness and contrast, these sliders adjust, well the brightness and contrast, amazingly enough.

Clarity is sharpness, you can sharpen now, though convention says that sharpening should be one of the last things you do in your work flow, and Photoshop (other editing packages) give you more control over sharpening.

Vibrance and saturation, both adjust the intensity of colours in your photo.

So, these are the main controls you can use when processing a RAW file, feel free to have a play with the other settings, to see the results of using them. Remember to watch your histogram as you adjust the settings.

Below is the same RAW file, with the sliders changed to show you the results of adjusting them.

Once you are complete with your RAW processing you have a couple of choices, you can click Open Image, which will open your processed RAW file in Photoshop for further editing, or you can click Save Image, to save it in DNG (adobe RAW), TIF, JPG or PSD format, for editing in Photoshop at a later time.

This tutorial only breezes over the entire process, but following it you should get a basic understanding of how RAW conversion works.

Below is the same photo, processed with a change of white balance, and some further processing in Photoshop, to show you the scope of what can be achieved from shooting in RAW. It is worth comparing the photo below, to the first one in the tutorial above, to see what shooting in RAW allows you to do.

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