A Series on using Photoshop
to Edit your Photographs
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This is a series on photo editing. We will look at whether or not you should edit your image or just use the one your camera produces. For editing and post-processing images there are a large number of software available. Personally, I use both Adobe Lightroom and Adobe Photoshop. Having used them for many years I am most comfortable with them so I will talk about Adobe Photoshop for this series. Whatever editing software you are comfortable using is also fine. The tools used may have different names or work slightly different in your chosen software, but they will give you nice results as well. Just remember the more you use it the better your results will be. 

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Part Three

As mentioned before these are common adjustments photographers make to their photos in Photoshop:
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  • Exposure: Adjusts the overall brightness of the photo 

  • Contrast: Controls the relationship between the light and dark areas in the photo 

  • White balance: Corrects the photo's overall color tone 

  • Levels: Adjusts the brightness, contrast, and color tones within an image 

  • Crop and straighten: Makes sure the photo is framed properly 

  • Color vibrancy and saturation: Work with these to improve the photo 

  • Sharpen: Sharpen the photo ​    ​​


​Let's look a little closer at them and see why we may want to make changes with them. 

Exposure - Adjusting exposure in Adobe Photoshop is a common way to enhance the brightness and detail of a photograph. Here’s how you can do it:
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​Open the Exposure Adjustment Panel

  • Go to the top menu and select Image > Adjustments > Exposure.
  • Alternatively, create an Adjustment Layer by clicking the adjustment layer button on your frequently used tool area. This will open a list of tools you can choose from. Click on Exposure and a small control panel will open that will allow you to make your adjustments. 
Adjust Exposure Settings

  • In the Exposure panel, you'll see three sliders:​
    • Exposure: Adjusts the overall brightness of the image.
    • Offset: Fine-tunes the shadows. A small change can make a significant difference.
    • Gamma Correction: Modifies the midtones for balanced adjustments.
  • Drag the sliders while observing the changes in your image to achieve the desired look.

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Contrast - Adjusting the contrast of a photograph in Adobe Photoshop is a very straightforward process. 
  • Go to the top menu and select Image > Adjustments > Contrast.
  • Alternatively, create an Adjustment Layer by clicking the adjustment layer button on your frequently used tool area. This will open a list of tools you can choose from. Click on Brightness/Contrast and a small control panel will open that will allow you to make your adjustments. 
Picture
Adjust the Contrast slider to increase or decrease contrast:
  • Move the slider to the right to increase contrast (make highlights brighter and shadows darker).
  • Move it to the left to decrease contrast.
Fine-tune the Brightness slider if needed to balance the overall lightness or darkness.


White Balance - Adjusting white balance in Photoshop is an essential step for ensuring accurate colors in a photograph. Here’s how you can do it effectively:
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  • Open Camera Raw:
    • Go to Filter > Camera Raw Filter.​​
Use the White Balance Tool:

  • Select the White Balance Tool (eyedropper icon).
  • Click on a neutral gray or white area in the image. This will adjust the white balance automatically.

Manual Adjustment:
  • Use the Temperature slider (blue to yellow) and the Tint slider (green to magenta) to fine-tune the white balance.


Levels and Curves - Adjusting Levels and Curves in Photoshop is a powerful way to fine-tune the tonal range and contrast of your photographs. 
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Open the Levels Panel:
  • Go to the top menu and select Image > Adjustments > Levels or Image > Adjustments > Curves to add a Levels adjustment layer or a curves adjustment layer by clicking the Adjustments Panel and choosing Levels or Curves.

  • Alternatively, create an Adjustment Layer by clicking the adjustment layer button on your frequently used tool area. This will open a list of tools you can choose from. Click on Levels or Curves and a small control panel will open that will allow you to make your adjustments. 
 
Understand the Histogram:

In photography, a histogram is a graphical representation of the tonal values (brightness levels) in an image. It provides a visual summary of the distribution of light and dark tones, helping photographers evaluate exposure and contrast.
Understanding a Histogram
  • Horizontal Axis: Represents the tonal range, from pure black (left) to pure white (right).
    • The left side corresponds to shadows (dark areas).
    • The middle represents midtones (gray or balanced tones).
    • The right side corresponds to highlights (bright areas).
  • Vertical Axis: Indicates the number of pixels at each tonal value. Peaks represent a higher concentration of pixels with that particular brightness.
Types of Histograms
  1. Balanced Histogram: A good distribution of tones with no clipping on either end. This usually means the image has a proper exposure.
  2. Clipped Shadows: A peak on the far left means shadow details are lost (underexposed areas).
  3. Clipped Highlights: A peak on the far right means highlight details are lost (overexposed areas).
  4. Low Contrast: A narrow histogram concentrated in the middle suggests a lack of tonal variation.
  5. High Contrast: A histogram that spans the full width indicates a wide tonal range.

Benefits of Using a Histogram
  1. Evaluates Exposure: Helps determine if an image is overexposed, underexposed, or properly exposed.
  2. Improves Composition: Assists in achieving balanced contrast and tonality.
  3. Post-Processing Guide: Provides insight into areas that may require adjustment in editing software.

​Practical ExampleImagine photographing a snowy landscape:
  • A histogram skewed heavily to the right might indicate blown-out highlights (overexposure).
  • Adjusting settings (like reducing the exposure) shifts the histogram leftward, preserving detail in the bright snow.
By understanding histograms, photographers can make informed decisions to create images with the desired exposure and tonal balance.
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When adjusting Levels:

  • Adjust the Sliders:
    • Black Slider (left): Move right to deepen shadows.
    • Midtone Slider (middle): Shift left or right to brighten or darken midtones.
    • White Slider (right): Move left to brighten highlights.

  • Output Sliders (Below):
  • Use these to compress the tonal range, often for stylistic effects.
 
  • Fine-Tune with Channels:
  • Use the dropdown menu to adjust individual color channels (Red, Green, Blue) for color correction.

​When adjusting Curves: 

​The Curves tool offers more precision and flexibility than Levels by allowing you to adjust specific tonal ranges via a graph.

  • Understand the Graph:
    • The horizontal axis represents the input levels (original tones).
    • The vertical axis represents the output levels (adjusted tones).

  • Manipulate the Curve:
    • Straight Line: No adjustments (linear tone).
    • Adding Points: Click on the curve to create control points.
      • Drag Up: Lightens the tone (output increases).
      • Drag Down: Darkens the tone (output decreases).
    • A subtle "S-curve" increases contrast (highlights brighter, shadows darker).

  • Target Specific Tone:
  • Adjust highlights (top-right), midtones (middle), and shadows (bottom-left).

  • Color Adjustments:
  • Adjust individual channels (Red, Green, Blue) for creative or corrective purposes.
Tips for Effective Use
  • Work Non-Destructively: Always use adjustment layers so changes can be modified later.
  • Combine Tools: Use Levels to correct global tonal issues and Curves for finer control.
  • Monitor the Histogram: Avoid clipping (losing detail) in shadows and highlights unless it's a stylistic choice.
  • Use the Eyedropper: The eyedropper tools in Levels can help set the black, white, and gray points for better tonal accuracy.


Crop and Straighten
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Use the Crop Tool
  • Select the Crop Tool:
    • From the Tools Panel on the left, click the Crop Tool).
  • Adjust the Crop Area:
    • Drag the corners or edges of the crop box to adjust the area you want to keep.
    • You can set a specific aspect ratio (e.g., 4:3, 16:9) in the options bar at the top by choosing a preset or entering custom dimensions.
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Straighten the Image
  • Straighten Using the Crop Tool:
    • In the options bar at the top, click the Straighten button (it looks like a ruler).
    • Draw a line along a part of the image that should be horizontal or vertical (e.g., a horizon or a building edge). Photoshop will automatically rotate the image to align with your line.
  • Manual Rotation:
    • Hover outside the corners of the crop box until the cursor changes to a rotation handle.
    • Click and drag to manually rotate the image.
Picture

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 Apply the Crop
  • Press Enter (Windows) or Return (Mac) to apply the crop and straighten adjustments


Fine-Tune Edges (Optional)
  • If any empty areas appear after straightening, you can fill them using:
    • Content-Aware Fill:
      • Go to Edit > Content-Aware Fill or use the Patch Tool.
    • Clone Stamp Tool:
      • Manually paint over gaps with sampled areas of the image.
      • ​
Adjusting Color, Vibrancy and Saturation: 

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Add an Adjustment Layer: Adjustment layers allow non-destructive editing.
  • Go to the Layers panel.
  • Click the Adjustment Layer icon (half-filled circle at the bottom of the panel).
  • Select Vibrance from the menu.​

Picture

Adjust Vibrance and Saturation: The Vibrance adjustment panel will appear:
  • Vibrance Slider: Increases the intensity of less-saturated colors without over-saturating already vivid tones. This is ideal for subtle enhancements.
  • Saturation Slider: Intensifies all colors uniformly. Use carefully to avoid unnatural results.
​​Use Selective Adjustments (Optional)
  • If you want to enhance specific colors:
  • Add a Hue/Saturation Adjustment Layer (Adjustment Layer > Hue/Saturation).
  • Use the drop-down menu to target specific color ranges (e.g., Reds, Greens, Blues).
  • Adjust the Saturation slider for the selected color.
 Fine-Tune Using Masks
  • If you want to apply adjustments to only part of the image, use the layer mask of the adjustment layer.
  • Select the mask, then use the Brush Tool (B) with black or white to hide or reveal adjustments in specific areas.


Sharpening your image:


Apply a Sharpening Filter

Option 1: Unsharp Mask
  1. Go to Filter > Sharpen > Unsharp Mask.
  2. Adjust the settings:
    • Amount: Controls the strength of the sharpening.
    • Radius: Defines the size of the area around edges to be sharpened.
    • Threshold: Determines the difference in brightness needed for an edge to be sharpened (lower values sharpen more details).
  3. Click OK to apply.

Option 2: Smart Sharpen
  1. Go to Filter > Sharpen > Smart Sharpen.
  2. Adjust the settings:
    • Amount: Adjusts the strength of the sharpening.
    • Radius: Controls the range of pixels affected.
    • Remove: Choose the type of blur to reduce (Gaussian Blur is common).
    • Enable Reduce Noise to avoid enhancing noise.
  3. Preview and click OK.

Fine-Tune the Effect
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  • Use a Layer Mask to apply sharpening selectively.
    1. Click the Add Layer Mask icon in the Layers panel.
    2. Paint over areas you don’t want to sharpen with a soft black brush.

Tips for Effective Sharpening
  • Avoid oversharpening, as it can introduce halos or make the image look unnatural.
  • Use sharpening as a final step after resizing and other edits.
  • Experiment with different radii and methods for various types of images (e.g., portraits vs. landscapes).


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​To Be Continued...