From Pigbert Wiki

Tricks

Changing Image Colour Without Losing Detail

1. Create a new layer with the desired colour
2. Place the layer on top of the layer of which the colour is to be changed
3. Change the layer mode to color

Example: Change Regional (Shirt's) Colour

1. pallette -> lasso -> select the rough area we want to change
2. Image -> Adjustments -> Hue/Saturation -> Edit:Reds (assume the shirt is red)
3. Mouse Click on the colour we want to change
4. Change the hue/saturation as wanted, move the bottom sensitivity range to avoid unwanted changes.

Saturation

Brightness & Contrast

Designed for quick and easy fix.

Auto Contrast: maps the darkest and lightest pixels in the image to black-and-white, causing highlights to appear lighter and shadows darker.

Levels

• Change the brightness of an image at three points: bright, midtone, dark.
• Can choose channel
• Usage: remove colour cast.

Curves

• Change the brightness of an image at all points
  • Click on the curve to add a point
  • To get rid of a point, drag it off the grid.
  • Click on the image to see where the colour of the pixel would appear on the curve
  • Ctrl+Click to lock a point
• Curve:
  • Horizontal axis: represents the original values of the selection
  • Vertical axis: represents the new output values
• Can choose channel

Colour

Color Balance

Intended to be used for general color correction.

Example: correct the colour of an old, used photo

• Options:
  • Shadows / Midtones / Highlights: start by midtones, as they comprise 90% of it.
  • Preserve Luminosity: maintains the brightness of the images as you shift colour.

Hue/Saturation

Intended to be used to change a single colour in the selection.

• Options:
  • Hue: moves around the colour wheel.
  • Saturation: 100% unsaturated (no colour) -> 0% -> 100% saturated (pure colour, no gray)
  • Lightness: controls the brightness of the image