AfterShot Pro 3 Curves

The Aftershot Pro 3 curves dialogue is a powerful adjustment tool for adjusting tone, contrast and colors in an image.

The Curves section is an intelligent combination of standard Curves and Levels tools found in many image editing programs.

If you're not familiar with curves or levels then you're in for an editing treat.  

What Curves Do

  1. Setting Shadow and Highlight values.
  2. Setting the tones and contrast.
  3. Color Correction.
  4. Setting White Balance.

The first item is the most important and here's how to set the shadows and highlights.

  1. Manually on the RGB setting.
  2. Manually using one or all of the White Point, Black Point or Grey Point tools.
  3. Manually on the individual color channels.

AfterShot Pro 3 Curves

Working With Curves

Moving the Triangles

The early April shot of some folks flying a kite looks OK but the Histogram tells a slightly different story.  

The histogram does not extend to the ends of the scale. This means there are no pure blacks or pure whites in the image.

By dragging the left bottom triangle to the left end of the historgram and the bottom right triangle to the right end of the histogram the curve became steeper, thereby increasing the contrast.  In addition, the mid-point slider was moved slightly to the left which boosted the contrast.

Moving the Curve

A very similar result would be obtained if the curve was adjusted by placing points and dragging the curve down at the left end and up at the right end.

This creates an "S" curve which increases contrast in the image.

To adjust the curve, do this ...

  1. Click anywhere on the line that extends from the bottom left to the top right of the diagram.  You have placed a point on the curve.
  2. Now click the point and move it down or up or left or right and watch what happens.  Moving down and/or to the left will darken the image and moving up or right will lighten the image.
  3. The accepted convention is to place a point about 1/3 of the way up from the bottom left and another about 2/3 of the way up from the bottom left.
  4. Dragging the first point down a bit and the second point up a bit will make the slope of the  line steeper and the contrast will increase.


Black, White and Grey Point Tools

What you do with these three tools is select one (white , for instance) and then click on a white spot in the image.  Do the same with the black pint tools and then with the grey point tool.

White and black are typically easy to find - the middle grey point can be a bit of a challenge.  Green grass will often work out or the darker parts of a sidewalk.  If the grey point is wrong then it may completely mess up your colors - just hit Ctrl-Z and try again.

This one little portion of the color panel is very powerful as you can see.  Each one of the three adjustments (moving the triangles, modifying the curve and using the Point Tools) produces an acceptable result.

You can, of course, using this portion of the color panel on a black and white image as well.

If you're into toning then some of the plugins and/or image presets may be of interest to you.  You can find a list or plugins and presets here ...

If not, then you can experiment with the Red, Green and Blue channels in the /curves dialogue - this is a discussion of toning values written by Terry.  The values were put together for PaintShop Pro and they work just as well in AfterShot Pro 3 Curves!



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