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Adobe Camera Raw

Introduction:

The Adobe Camera Raw (ACR) converter is used to open digital Raw files. There are a whole number of settings that can be applied to the image before it is opened in Photoshop. There are essentially the same changes that the camera would apply if you were to shoot jpeg. The greatest advantage of Raw is the ability to apply these changes at a later date and the vary amount of correction that can be applied.

Camera Raw:

Once you open a Raw image using Photoshop you get a dialog like this.

In the upper left you have a set of standard editing tools. I usually leave these changes until the image is in Photoshop. On the bottom left you have a zoom level displayed in a percent and the Same Image button. This lets you save the image with the changes you made as a different file. In the bottom middle you have the setting for color space, bit depth, and resolution. By clicking on this line you can choose to open the image in a different color space, bit depth, or resolution. (I prefer to use ProPhoto RGB since most digital sensors can capture colors outside the Adobe RGB range. Once the image is opened in Photoshop I immediately convert it to Adobe RGB. The ProPhoto RGB color space is too huge to make any changes, even in 16-bit mode and not have them result in posterization.) On the bottom right you have three buttons. The Open Image button opens it in Photoshop with the changes you made. Cancel button cancels your changes and closes the windows. The Done button writes your changes to the .xmp sidecar file or to the camera Raw database. I prefer to have the changes in a sidecar file because if I move the image file, the changes .xmp file moves with it. On the right hand side you have a histogram that updates as you make changes. The two upwards arrows in the corners enable and disable shadow and highlight clipping. Shadow clipping will show as blue and highlight as red. Now lets take a look at the right hand controls. There are several tabs that can be selected. We will start with the basic tab.

This is the Basic Tab In this tab you can set your white balance from a set of preconfigured options in a dropdown menu. You can also set a custom white balance using the Temperature and Tint sliders. Here you can click on Auto and the ACR will attempt to correct the image as best as it can. It works quite well most of the time and you can always fine tune it to your liking using the sliders. Exposure - adjust the exposure of the image Recovery - adjustment for darkening highlights Fill Light - slider for brightening shadows Blacks - adjusts the density at which pixels go black Brightness - adjusts brightness Contrast - contrast adjustment Here you can choose to convert the image to grayscale. If you do this, the Vibrance and Saturation sliders become inactive. Saturation - adjusts color saturation from mono (-100) to double (+100) Vibrance - adjusts saturation so that colors are not clipped as they approach full saturation. Prevents skin tones from oversaturation.

This is the first part of the Tone Curve Tab In the parametric tab you can use the curve to adjust the values in specific tonal ranges. The areas affected (Shadows, Darks, Lights, Highlights) are dependant on the setting of the split control sliders at the bottom. For example, to brighten the shadows, you would drag the shadows slider to the right. Dragging any slider to the right will brighten that particular tone.

This is the second part of the Tone Curve Tab Here you can also adjust the tone curve but in a way that is more recognizable from the Curves Tool. Simply drag any point along the curve to adjust the tone. This works exactly the same as the Curves Tool except that you cannot edit individual color channels.

This is the Detail tab Here you can set the amount of Sharpening. I always set this down to 0. Sharpening should be the absolute last step in your workflow. The noise reduction using these sliders works quite well, but you are better off using a standalone or plug-in program such as Noise Ninja or Neat Image. I always set both Luminance and Color to 0 and fix noise in Photoshop. Personally I prefer Noise Ninja over Neat Image for its speed. They both give very good results, but if you take the time with Noise Ninja and create your own custom Noise Profiles for each ISO level it performs much better than Neat Image.

This is the Hue Saturation Luminance / Grayscale Tab Using the Hue tab you can adjust the actual color. For example you can change all blues from cyan to magenta.

This is the Hue Saturation Luminance / Grayscale Tab In the Saturation tab you change the intensity or vividness of each color. For instance you can change the reds from a gray to a super saturated red.

This is the Hue Saturation Luminance / Grayscale Tab In the Luminance tab you change the brightness of each color.

This is the Split Toning Tab Split toning is generally used for coloring a grayscale image. You can adjust the hue and saturation sliders for highlights and shadows. The hue slider sets the color of the tone and the saturation slider changes the intensity of the hue. The balance slider changes the balance between the shadows and highlights.

This is the Lens Corrections tab Here you can adjust any chromatic aberration that might be visible. These are either red / cyan or blue / yellow fringing. These often happen when you have a dark object against a very bright background. Lower down you can correct lens vignetting. Vignetting is a lens defect that causes the corners of an image to darken. The amount slider changes the brightening of these dark areas. The Midpoint slider changes how far from the corners the effect reaches.

This is the Camera Calibration tab Here you can adjust the colors as they are rendered by the Adobe Camera Raw plug-in for you camera. The shadow tint slider is used to remove a color cast in the shadows. Here you can adjust the hue for the red, green, and blue primary colors as well as their saturation.

This is the Presets tab Here you can save a set of changes that you used to develop a certain image for future use. For example you can create a preset for a certain camera / lens / light combination. Then in the future when you have an image shot with the same settings you do not have to adjust anything. You simply load the preset that you created and open the image. It can also be useful for large volume processing like weddings etc.

This whole slew of options can be a little too much to digest all at once, but as you use it more it will become almost second nature. Some people argue that you should be using manufacturer's Raw software to edit Raw images. This is because the manufacturer calibrates each camera and stores variations in the camera. This data is then written to the Raw image as metadata which the manufacturer software understands. Unfortunately this data was not given to third party software developers. This was a Nikon issue, but it seems to have been resolved between Adobe and Nikon in the ACR 3.3 version which fully supports cameras like the D200 and the D2X. The latest version of ACR supports all Nikon DSLR's.

Cheers