Sharpening and Noise Reduction

Sharpening and Noise Reduction

Understanding Sharpening

  • Sharpening is a post-production technique used to enhance the definition of edges in an image.
  • It works by increasing the contrast between adjacent pixels to create a more pronounced edge.
  • Careful use of sharpening can bring out fine details in a photograph, making it appear more visually striking.
  • Over-sharpening, however, can lead to an overly crunchy looking image and exacerbate digital noise.

Unsharp Mask

  • The Unsharp Mask is a common sharpening tool found in many photo-editing software. It’s named after an old film technique and not as a description of its effect.
  • It usually consists of three controls: Amount, Radius, and Threshold.
  • Amount controls how much contrast is added at the edges, Radius determines how wide the edge rims become, and Threshold sets the level of difference between pixels that the effect will be applied to.

Understanding Noise Reduction

  • Noise in a digital image can appear as random speckles of colour or faint specks in a photo, particularly in shadows or plain colours. It often occurs when shooting in low-light conditions.
  • Noise Reduction is a post-production technique used to reduce this noise, resulting in a smoother and cleaner image.
  • Different types of noise require different types of noise reduction: Luminance Noise (grainy black and white specks) and Colour Noise (coloured specks). Most editing software will have individual controls for each.
  • It’s essential not to overdo noise reduction as it can result in loss of detail, creating an overly smooth, plastic texture in photos.

Using Sharpening and Noise Reduction Together

  • Using sharpening and noise reduction techniques together can drastically improve the quality of an image.
  • Sharpening can spruce up an image by highlighting details, while noise reduction can remove unnecessary distractions.
  • However, a balance must be achieved. Overusing one or both can lead to a degraded image. Too much sharpening can produce noise, and too much noise reduction can eliminate detail.
  • Practising using these tools on various images will help you understand their effects and learn how to balance them for optimal results.