Workshop Index    
  1. Camera settings
  5. Jpeg work flow
  6. RAW flow
  7. File details
  8. Storage
  9. Computer set up and basic work flow
  10. Image selection
  11. Transferring images between folders
  12. RAW processing
  13. Sharpening
  14. Shadow/highlight tool
  15. Correcting under-exposed images
  16. Overexposed images
  17. Reducing digital noise
  18. Correcting sloping horizons
  19. Mono conversions
  20. Layers
  21. False snow
  22. Producing a pencil sketch
  23. Using a layer to burn and dodge
  24. Curves
  25. Altering contrast using curves
  26. Altering part of the curve
  27. Pysadelic curves
  28. Curves and monochrome
  29. IR conversions
  30. HDR (High Dynamic Range) processing
  31. Highlight & Shadow in Photomatix
  32. Book list
  33. Return to home page
  

Curves

Any thing you can do in levels you can do more accurately in curves. At first curves may seem a bit daunting but, with a little practice, you'll soon only use levels for basic adjustments. For example before using curves I set the shadow and highlight points to the ends of the histogram in levels, this may be the only adjustment required but if you wish to make fine adjustments, especially to the mid-tone range curves will do a better job.

Curves can be used to adjust contrast, shadow and highlight adjustment; colour correction, mid-tone contrast, and any of these adjustments can be applied to any portion of the image preferably using a layer for each adjustment. In other words you have complete control over your image just as one did in the darkroom only more so.

 

This is the curves display.

The default grid is 4 x4 to show the 10 x 10 grid shown above alt click on any intersection on the grid. You can make the display larger or smaller by clicking on the icon with the arrow in the bottom RH corner.

The graph line depicts the tonal range of the image from black (D max) 0 brightness levels; also sometimes referred to as the ‘shadow point'; in the LH bottom corner to white (Dmin) 255 brightness levels; also sometimes referred to as the ‘highlight point'; in the top RH corner. The vertical axis shows output values and the horizontal axis input values.

The eye droppers can be used to set , left to right, D max, mid-grey, D min.