1. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
"Digital Media Primer" Yue-Ling Wong, Copyright (c)2016 by Pearson Education, Inc. All rights reserved.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

2. Chapter 3 Capturing and Editing Digital Images
Part 4
Color and Tonal Adjustment
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3. In this lecture, you will learn:
how to interpret image histograms
how to perform tonal adjustments on images
how to improve image contrast by stretching the histogram
how to use Curve Adjustment tool to adjust color and tonal range
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4. Color Adjustment Tools
adjusting the histogram
color balance
color curves
hue/saturation
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5. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Histogram
A bar chart that shows the relative number of pixels plotted against the color value
Histogram
X-axis: the color value
Y-axis: relative number of pixels that have the corresponding color value
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6. Histogram Self-Test Exercise
(A)-(v), (B)-(iv), (C)-(iii), (D)-(ii), (E)-(i)
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7. Applying Histograms to Adjustment of Brightness and Contrast
Move the sliders to modify the image’s brightness and contrast
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8. Applying Histograms to Adjustment of Brightness and Contrast
Define the darkest color (shadow) in the image
Define the 50% intensity of the color (midtone) in the image
Define the brightness color (highlight) in the image
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9. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Use of Shadow Slider
The originally second darkest color is now black.
Any color darker than this second darkest color is also black.
the shadow slider has been moved to where the bar for the second darkest color of the image is
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

10. Use of Highlight Slider
The originally second brightest color is now white.
Any color brightest than this second brightest color is also white.
the highlight slider has been moved to where the bar for the second brightest color of the image is
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

11. Use of Shadow and Highlight Sliders to Stretch the Histogram
The originally brightest color is now white.
The originally darkest color is now black.
All other colors are mapped in between in the same relationship of their original gray tones.
Increased contrast
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12. Photoshop's Image > Adjustments > Levels...
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13. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Use of Midtone Slider
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

14. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Use of Midtone Slider
The third brightest color (originally a LIGHT gray) now is set to be the miidtone (i.e. the middle gray)
All other colors are remapped accordingly.
Overall tone of the image is DARKER.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

15. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Use of Midtone Slider
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

16. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Use of Midtone Slider
The darkest color (originally a DARK gray) now is set to be the miidtone (i.e. the middle gray)
All other colors are remapped accordingly.
Overall tone of the image is LIGHTER.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

17. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Also see the interactive tutorial:
Understanding and Applying Histograms
There are two parts of this learning aid: an interactive tutorial and practice exercises. Tutorial: Explains how to interpret an image’s histogram and make tonal adjustments using histograms. Practive Exercises: Exercise I: Reading Histograms. Exercise II: Improving Image Contrast and Brightness.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

18. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Curve Adjustment Tool
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19. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Curve Adjustment Tool
Lets you remap the color and tonal range by using the shape of a 2-D curve
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20. Curve Adjustment Tool A diagonal line: No change in color/tonal range
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21. Below the Diagonal Line  Darken
A curve below the diagonal line:
The color/tonal values will be lowered
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22. Above the Diagonal Line  Brighten
A curve above the diagonal line:
The color/tonal values will be increased
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23. Above or Below the Diagonal Line  Brighten or Darken
Part of the curve is below the diagonal line
and the other part above the line
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24. Above or Below the Diagonal Line  Brighten or Darken
The color/tonal values within this range will be lowered
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25. Above or Below the Diagonal Line  Brighten or Darken
Above the diagonal line:
The color/tonal values within this range will be increased
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26. Steeper Curve  Increase Contrast
A steeper curve:
The in color/tonal range will be widened—higher in contrast
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27. Less Steep  Lower Contrast
A less steep curve:
The in color/tonal range will be narrowed—lower in contrast
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

28. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Also see the interactive tutorial:
Understanding and Applying Curves for Color Adjustments
An interactive tutorial and exercises help you understand the Curves tool for image adjustment.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

29. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Questions
Note to instructor:
Depending on your preference, you may want to go over the review questions at the end of this lecture as an instant review or at the beginning of next lecture to refresh students' memory of this lecture.
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

30. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
Match each of the bars in the histogram to the color it represents. ii
iii A B C i
A-i, B-ii, C-iii
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31. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
To maximize the contrast and tonal range of this image, what changes of the sliders should be made?
move the shadow slider to the leftmost bar, and the highlight slider to the rightmost bar
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

32. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
Predict the resulting grays that are caused by the adjustment made to the image (shown in the histogram). Specify whether it is black, white, or gray. If it is gray, estimate an RGB value for that gray. A B C
A-black 0, B-black 0, C-middle gray 128
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

33. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
Predict the resulting grays that are caused by the adjustment made to the image (shown in the histogram). Specify whether it is black, white, or gray. If it is gray, estimate an RGB value for that gray. A B C
A-middle gray 128, B and C-light grays
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

34. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
Predict the resulting grays that are caused by the adjustment made to the image (shown in the histogram). Specify whether it is black, white, or gray. If it is gray, estimate an RGB value for that gray. A B C
A-middle gray 128, B and C-white 255
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

35. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
Predict the resulting grays that are caused by the adjustment made to the image (shown in the histogram). Specify whether it is black, white, or gray. If it is gray, estimate an RGB value for that gray. A B C
A-black 0, B-black 0, C-white 255
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

36. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
After the adjustment, the image will be ___.
brighter
darker A
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37. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
___ of the curve is steeper than the default diagonal line, and thus after the adjustment, the contrast for the tonal range within that region will be ___.
Region A; higher
Region A; lower
Region B; higher
Region B; lower A
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

38. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
After the adjustment, the highlights (Region C) will become ___.
brighter
darker A
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39. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
After the adjustment, the shadows (Region A) will become ___.
brighter
darker B
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.

40. © 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.
Review Question
The curve in ___ is steeper than the default diagonal line, and thus after the adjustment, the contrast for the tonal range in that region will become ___.
Region A; higher
Region A; lower
Region B; higher
Region B; lower
Region C; higher
Region C; lower C
© 2016 Pearson Education, Inc., Hoboken, NJ. All rights reserved.