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 layers to produce a painting effect
    24. Using a layer to burn and dodge
    25. Curves
    26. Altering contrast using curves
    27. Altering part of the curve
    28. Pysadelic curves
    29. Curves and monochrome
    30. IR conversions
    31. HDR (High Dynamic Range) processing
    32. Highlight & Shadow in Photomatix
    33. Book list
    34. 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.