Curves in Photoshop

Curves is an adjustment tool that allows you to change the brightness and tonal values of an image using a graph.

By changing the curve, you can control different tonal areas of the image.

Curves provides more precise control than simple brightness adjustments.

• Correct image brightness
• Improve contrast
• Control shadows
• Control highlights
• Adjust midtones
• Create creative color effects

Curves can be opened from the Image menu.

Image → Adjustments → Curves

You can also use a Curves Adjustment Layer for a more flexible editing workflow.

The Curves graph represents the tonal values of the image.

Output
  ↑
  │        /
  │       /
  │      /
  │     /
  │    /
  └──────────────→ Input

The horizontal axis represents input tones and the vertical axis represents output tones.

Input represents the original tonal value, while Output represents the resulting tonal value after the curve adjustment.

Input → Curves Adjustment → Output

Moving points on the curve changes how input tones are converted to output tones.

When Curves is first opened, the graph normally displays a diagonal line.

Output
  ↑
  │       /
  │      /
  │     /
  │    /
  │   /
  └────────────→ Input

This represents the original relationship between input and output tones.

You can click on the curve to add a control point.

The point can then be moved to change the tonal values in that part of the image.

Before:
──────────────

After:
──────●───────
      ↑
  Control Point

Moving a curve point upward generally makes the selected tonal range brighter.

Original
    ●

Move Up
    ↑
    ●
    │
  Brighter Result

Moving a curve point downward generally makes the selected tonal range darker.

Original
    ●

Move Down
    ●
    ↓
  Darker Result

The lower-left area of the Curves graph represents darker tones or shadows.

Shadows
   ↓
●───────────────
 \
  \
   \
    └───────────

Adjusting this area affects darker parts of the image.

The middle area of the Curves graph represents midtones.

Adjusting this area can change the brightness of middle-toned parts of the image without treating every tone equally.

The upper-right area of the Curves graph represents highlights.

Adjusting this area affects brighter areas of the image.

Add a point around the middle of the curve and move it upward.

        ●
       /
      /
─────/────────
    ↑
 Brighten Midtones

This can brighten the main visible details of many photographs.

A point in the middle of the curve can be moved downward to darken the corresponding tonal range.

Use small changes to avoid making the image too dark.

An S-curve is a common technique for increasing contrast.

Output
  ↑
  │        ●
  │      /
  │    /
  │  ●
  │ /
  └────────────→ Input

The darker area is moved slightly down and the lighter area is moved slightly up.

A gentle curve can create a softer tonal change.

Small adjustments are often better than extreme curve movements.

Curves provides detailed control over contrast because you can adjust different tonal areas independently.

Shadows → Control
Midtones → Control
Highlights → Control

In an RGB image, Curves can be applied to the composite RGB channel.

This changes the overall tonal appearance of the image.

Curves can also be applied separately to individual color channels such as Red, Green and Blue.

This allows Curves to be used for creative color correction and color grading.

Individual color channels can be adjusted to reduce unwanted color casts.

Make small changes and compare the result with the original photograph.

Curves can be applied as an Adjustment Layer instead of directly changing the image pixels.

Original Image
      ↓
Curves Adjustment Layer
      ↓
Edited Appearance

This makes the adjustment easier to edit later.

A Curves Adjustment Layer can be combined with a layer mask.

Curves Adjustment
        +
    Layer Mask
        ↓
Selected Areas

This allows you to apply the Curves effect only where it is needed.

Suppose a photograph is slightly dark.

1. Create a Curves Adjustment Layer.
2. Add a point in the midtone area.
3. Move the point slightly upward.
4. Check the highlights.
5. Compare the result with the original.

To create stronger contrast, use a gentle S-curve.

1. Create a Curves Adjustment Layer.
2. Add a point in the shadow area.
3. Move the shadow point slightly downward.
4. Add a point in the highlight area.
5. Move the highlight point slightly upward.
6. Review the image.

• Making extreme curve movements
• Creating excessive contrast
• Making shadows completely black
• Making highlights completely white
• Adding too many control points
• Changing colors accidentally
• Ignoring skin tones
• Not comparing with the original image

Practice Curves with a sample photograph:

1. Open a photograph.
2. Create a Curves Adjustment Layer.
3. Observe the diagonal curve.
4. Add a point in the midtones.
5. Move it upward slightly.
6. Reset or undo the change.
7. Create a gentle S-curve.
8. Compare the contrast.
9. Try adjusting an individual color channel.
10. Save the best result.

Create a simple promotional graphic and improve the photograph using Curves.

┌──────────────────────────────┐
│       SOOPRO PATHSHALA       │
│                              │
│       [ PHOTO ]              │
│                              │
│        ADCA COURSE           │
│                              │
│          JOIN NOW            │
└──────────────────────────────┘

Use a gentle Curves adjustment to improve the contrast while keeping the photograph natural.

1. Open the image.
2. Keep the original image safe.
3. Create a Curves Adjustment Layer.
4. Study the curve and histogram.
5. Adjust shadows carefully.
6. Adjust midtones carefully.
7. Adjust highlights carefully.
8. Use individual color channels when required.
9. Compare the result with the original.
10. Save the Photoshop project.

Curves is a powerful Photoshop adjustment that provides detailed control over the brightness, contrast and tonal range of an image.

The graph allows you to control shadows, midtones and highlights by adding and moving control points.

Curves can also be used with individual RGB channels for color correction and creative color grading. Using a Curves Adjustment Layer provides a flexible and non-destructive workflow.