Doug Johnson Productions

Scope guide · Picture & exposure

Waveform

Connect brightness and component levels to horizontal image position. Inspect a face, screen or highlight while keeping the shot in context.

ExpressProfessional

Learn & Reference / Scope library / Waveform

Where is that exposure difference in the picture?

Add this view from Add scope > Waveform, then choose the input you want to inspect. Use the pane's i button for its in-app reading guide.

Read this example.

Fresh studio-pair capture. The white Y′ panel is followed by red, green and blue component panels; linear Y Histogram is lower right.
Fresh studio-pair capture. The white Y′ panel is followed by red, green and blue component panels; linear Y Histogram is lower right. Click the image for a larger view.
  1. The faces occupy different horizontal bands. Inspect those same relative positions in the first, white Y′ panel; each band also includes background and clothing at that X position.
  2. The white fabric contributes the high plateau on the left of the white Y′ panel. Faces contribute middle-to-upper levels, while jacket and dark cloth add lower levels.
  3. The red, green and blue panels repeat the scene by component. Compare corresponding regions to investigate a cast on a neutral subject.

Try it yourself.

  1. Choose Studio pair / neutral baseline in Picture and Waveform.
  2. Select Y′, then Y′R′G′B′ parade to compare encoded luma and component relationships.
  3. Use a Professional analysis region around one face to identify its contribution more precisely.

Useful controls.

  • Express includes Y, Y′ and fixed-color parades. Professional adds individual components, hue, saturation, chroma and RGB-derived quantities.
  • Display chooses the component. Trace adjusts intensity, width and persistence; wheel zoom and vertical drag inspect level ranges.
  • Optional Minimum, Maximum and Average guides show current-frame statistics for samples included in analysis.

Y′ is encoded luma; Y is linear-light luminance. Relate readings to the subject and intended look rather than a universal face-exposure target.