Digital Focus
Basic Editing in LR 2.5 –
In the last issue, I discussed the contents of the left vertical panel group of the Develop Module in Lightroom (LR). In this issue, I will explain the operations of the different panels in the right vertical panel group. This is the most important component of LR as this includes controls for globally adjusting the color and tonal scale of your photos, as well as for making local adjustments.
One of the outstanding features of LR is the fact that all the adjustments you make in LR are non-destructive. This means whether you are working with camera raw file or a rendered file such as JPEG and TIFF, the original file is not altered. The edits are stored in LR as a set of instructions that are visually applied to your photo. Because the edits are not applied real time, you can explore and create different versions of your photo without degrading your original image data. Each version in itself is just a set of instructions and therefore does not consume hardisk space.
The right vertical panel contains the following horizontal panels: the Histogram, the Tool strip and the Adjustment panels (Image 01). I will discuss the tools in the Tool strip later. For this issue I will concentrate on the Histogram panel and the Adjustments panels.
Histogram Panel
The Histogram panel contains the histogram of the selected photo (Image 02). A histogram is a bar chart where each bar represents the number of pixels in a photo at each luminance or brightness percentage. (Photoshop uses luminance levels instead of percentage). A properly exposed photo is one whose histogram stretches from the left side of the panel to the right side, indicating that the photo takes full advantage of the tonal scale (Image 03). A histogram that does not use the full tonal range can result in a dull image that lacks contrast (Image 04). On the other hand, spikes at either end of the histogram is an indication of shadow or highlight clipping (Image 05). Clipping can result in the loss of image detail.
The histogram in LR is made up of three layers of color representing the Red, Green and Blue channels. When all three channels overlap, it will appear in the histogram as gray; when red and green overlap, it will appear as yellow; when red and blue overlap, it will appear as magenta; and when green and blue overlap, it will appear as cyan. See Image 06.
The starting point of any tonal editing in LR is the histogram. The Histogram panel in the Develop module, unlike that of the Library module, is a working tool in itself. See below: Using the Histogram as an Adjustment Tool.
Viewing RGB Color Values
The area under the Histogram in the Develop module (which I call the Info pane) displays the camera settings. But, as you mouse-over your photo, it will display the RGB color values for individual pixels appearing under the Hand or Zoom tool (Image 07). You can use this feature to determine whether any areas of the photo are clipped (the R,G, or B values is 0% black or 100% white). If at least one channel in the clipped area has color, then there are still some detail in the photo. You can also use this feature to determine if there is a color cast on neutral colors in the photo. On neutral colors, the R, G, and B must be equal or nearly equal to each other.
Using the Histogram
as an Adjustment Tool
You can make adjustments directly on the histogram. Place your cursor inside the histogram and it changes into a double-arrow pointer allowing you to drag the pixel bars of the histogram (Image 08). Click and drag on the area you want to adjust; the affected area is highlighted, and the affected tone control and value are displayed in the Info pane (Image 09). As you drag the pointer left or right to adjust the histogram, the corresponding sliders in the Basic panel (Exposure, Recovery, Fill Light and Blacks) will also move to reflect the changes in the tonal values.
Previewing Highlight
and Shadow Clippings
You can preview if any part of your photo is being clipped. Clipping is the shifting of pixel values to the highest highlight value or the lowest shadow value. Clipped areas are either completely white (washed out) or completely black (no image detail). You can preview the clipped areas of the original photo to determine their importance or preview the areas that are being clipped as you make tonal adjustments.
One way of previewing the highlight and shadow clippings is by turning on the Clipping Indicators at the top of the histogram (Image 10). The black triangle at the left is the indicator for the shadow clipping, and the white triangle at the right is the indicator for the highlight clipping. To turn on the indicators you can do one of these:
• Click on any one of them. An indicator that is turned on will be placed in a box (Image 11).
• Mouse-over on either one of them. The indicator is temporarily turned on as long as the mouse is over it.
• Press the keyboard shortcut J and both indicators will turn on simultaneously. Pressing J again will turn the indicators off.
When you do any one of these procedures and some part of your photo is clipped, the shadow clipping will appear on the document window highlighted in blue and the highlight clipping in red (Image 12). In addition, the indicator turns white when clipping in all channels occur. A colored clipping indicator, e.g., cyan, means one or two channels are clipped (Image 13).
Another way of previewing the clippings is by pressing simultaneously Alt (Windows) or Option (Mac OS) and the slider control of either Exposure, Recovery, or Blacks in the Basic panel. For the Exposure and Recovery sliders, the image turns black and clipped areas appear white. For the Blacks slider, the image turns white and clipped areas appear black. Colored areas indicate clipping in only one color channel (red, green, or blue) or two color channels (cyan, magenta, yellow).
