Introduction to Adobe Camera RAW
By Dan Moughamian

This is, I hope, the first of many articles by new contributor to the site, Dan Moughamian. It is a subject I feel strongly that everyone, who gets serious about photography, should know about. I have been using RAW files for a couple of years now. At first I found the whole thing was just too much extra work, but now I never use JPEGS any more, except for output to the web. Once you get to grips with RAW it's like having a new camera outfit, better in fact, the quantum leap in the quality of your pictures has to be seen to be believed. There is a lot of information here so, read it all carefully, then get out there and try it for yourself. - Geoff

Many of you may have heard about shooting “raw files” with your digital camera. What are raw files, exactly? The simplest way to understand raw images, is to remember that they are:

1. A proprietary picture format (in the same sense that a JPEG is a picture format), available in many point-and-shoot cameras, and all Digital SLR cameras on the market today. To benefit from RAW formats, your best option is to use a Photoshop and Photoshop Elements feature called Adobe Camera RAW (or ACR).
2. RAW picture files are the equivalent of a film negative from your old camera. They represent the unaltered light and colour data that your camera has captured. No alterations of any kind have been applied in the camera. This means you have more control over the final look of your photo (a good thing!). See your camera's instruction manual for details on how to shoot RAW files.

This tutorial covers the fundamental ACR features, which can combine to make your photos more vibrant in terms of colour and more balanced in terms of contrast.

ACR is regularly updated to support the latest cameras, and the latest version is freely downloadable from Adobe (Version 4.3, will only work with Photoshop CS3 and version 5 onwards of Elements, if you are using CS2 or earlier stick with what you have). It is launched directly from your copy of Photoshop when you select a RAW file from the File > Open dialog.

This is what the ACR window looks like when it first opens:

(Click on the picture above to open a larger version in a floating window then you can refer to it while reading the text. You may need to click 'allow popups' in your browser.)

There are many options for improving your raw photos with ACR. First notice the toolbar across the top of the window. From left to right we have:

1. Zoom Tool - click to zoom in on your image to see more detail; alt-option click to zoom out.
2. Hand Tool - click and drag the image to move it inside the window, if it is too large to fit.
3. White Balance Tool - click a specific colour point on your image that represents a pure white (or near-white) tone, to remove colour casts. When you use this tool, the White Balance pop-up menu (L) will change to “custom”, and the temperature slider (M) will move to a non-zero value.
4. Colour Sampler Tool - click to create a “marker” on a specific area of colour; mostly used by professionals who need to reproduce a specific colour value for a printer or press.
5. Crop Tool - click and drag across the image to remove the edges, what you see inside the box is what will remain.
6. Straighten Tool - click and drag along the horizon. This will automatically rotate your image to straighten the horizon.
7. Retouch Tool - Use this to remove specks, dust marks and other distractions that might’ve resulted from a dirty lens or just bad timing when taking the picture. (This will be covered in a future article.)
8. Red Eye Removal Tool - works similarly to other Adobe Red Eye Tools that you may have used already.
9. ACR Preferences - use to set up ACR settings. (This will be covered in a future article.)
10. & K. - Rotate Counter-clockwise and Rotate Right Clockwise. Changes your image from landscape to portrait or vice versa.

Non-image-altering controls:

Preview checkbox. Click this on and off to see what your raw image looks like with and without the changes you have applied.

Double-arrow button. Expands the ACR window to cover your entire screen. This can be useful if you have a distracting desktop wallpaper with garish colours.

Histogram (top right corner). This is a graphical representation of where the colour data in your image resides relative to its tonality. Every digital image is made of Red, Green and Blue (also called “RGB colour”), mixed together in millions of lighter and darker combinations to create an accurate representation of the scene you photographed. The ACR Histogram also shows Cyan, Magenta and Yellow (part of “CMYK colour”, used by printing presses).

To interpret your histogram, imagine it broken into equal quarters. Every colour shown in the left-most quarter are deep shadow tones, everything in the middle two quarters are “mid-tone” colours, and everything that falls in the right most quarter are the highlight colours. The higher the colour spike, the more of that colour is present in that part of the image. In this sunset image there is a great deal of colour distributed among the darker parts of the image, which is what we’d expect.

Directly under the Histogram, you can see this RAW photo’s exposure settings; the aperture was f/8 with a shutter speed of 1/100 second, shot at the 28mm setting on my lens. Because this image is relatively level and because I intended to create a darker image with a warm glow, I only need to make a few adjustments.
To make these adjustments we can use the slider controls that are organised in a column along the right edge of the ACR window. From top to bottom we have:

12. White Balance - this menu mimics the options you see in your camera white balance menu, but in this case says “Custom” (see next item)
13. Temperature - the White Balance menu says “Custom” is because I dragged the Temperature slider to the left, in order to re-balance the image’s overall colour scheme. In this case, it was too warm. Even the then-blue sky was orange-ish, so I moved the slider to a value of 3850 degrees Kelvin. Moving the Temperature slider in the other direction, beyond 5000 Kelvin, will make and image more “warm”. How far you move it is up to you and is mostly subjective.
14. Tint - this slider is used to further tweak the overall colour balance of your image, pushing all colours either towards a slightly more green, or more magenta cast. I say slightly because nudging this slider more than a few value points in either direction can result in a very unrealistic looking image. In this case I chose a value of +4 to help boost the warmth of the image slightly and bring out the colours I was seeing in the water at that time.
15. Exposure - this slider controls the overall brightness or darkness of the image. It affects all tones equally, just as the exposure settings in your camera would. Since this shot was a bit under-exposed, even for my intentions, I have increased the default raw exposure 1/3 of a stop to +.35.
16. Recovery - this slider is used to recover very bright highlights in an image, that have turned pure white, often as a result of pushing the exposure value. No such highlights are present here so the setting remains unchanged. One common use for this is bringing texture back into white clouds.
17. Fill Light - simulates a fill-flash on your camera. Here I want the plants in the foreground to have just a bit of visible detail. Since they were a dark mass to start, I pushed the slider value to 32. As you experiment with your own images you will get a feel for the “safe range” of each ACR slider. Some can be pushed quite a lot, others only a few points before they have a harsh impact.
18. Blacks - this slider is used to correct over-exposed shadow detail areas, by darkening them a bit to enhance contrast and the realism of the image. This is not a problem here so it remains unchanged.
19. Brightness - this slider, defaulted to 50, affects the highlight portion of your image with minimal effect on the mid-tones or shadows. This setting needs no change here because we want to keep the darker mood.
20. Contrast - default value is 25, this slider affects how flat or contrasty an image is. Since we had a very contrasty image to start with, I am going to decrease this a small amount to 22. In my experience, if you have a reasonably good exposure, and subsequently tweak the Exposure, Fill, Recovery and Black sliders correctly, little to no Contrast adjustments will be needed.
21. Clarity - this slider gives the appearance of enhanced sharpness for well defined edge details, by increasing the mid-tone contrast in the image. Because my image has a softer appearance due to many dark, rounded shapes, this setting will only have a marginal effect here, but I have bumped the slider to a value of 21, to see more definition in the plants.
22. Vibrance - this slider will increase the saturation only for colours that are muted, while leaving the more intense colours unaltered. Since few muted colours exist here, I left the slider at zero, however I use this setting often in more brightly lit images. One great use for this slider is to enhance the saturation of people’s clothes or surroundings, while maintaining much of their natural skin tone.
23. Saturation - this slider will increase the saturation for all colours equally. Since I already have a very colourful image I am only going to nudge this setting to a value of +2. Be warned: over-use of the saturation slider can -and often does- ruin the realism of images. Best used in small measures! :-)

    Below is the original uncorrected image and under it the final adjusted image.

     

    If you have questions about ACR, or would like to suggest specific ACR features you’d like to see covered next time, please post your feedback in our forum. I will be happy to answer your questions as often as I am able. Note: more Photoshop editing and ACR editing techniques are coming in April!

    Dan Moughamian, Owner of Colortrails.com