Canon CanoScan D660U Canon Plug-in Module CS-U3.9 User's Guide - Page 44

The Relationship Between the Tone Curve, and Image Brightness, Value = 1, Value > 1 - manual

Page 44 highlights

STEP 3 The Relationship Between the Tone Curve and Image Brightness Tone curve values fall with a range of 0.01 to 10.00. A value of 1 appears as a straight line in the graph, and if the value is any value other than one, the line on the graph will appear curved. The relationship between the shape of the curve and image brightness is explained below. Value = 1 Input and output and are equal and the curve appears as a straight line, and the input image is displayed on the screen without adjustment. Value > 1 The data bends upward over the range of input values from shadows to highlights, making the adjusted image brighter in the display. Value < 1 The data bends downward over the range of input values from shadows to highlights, making the adjusted image darker in the display. Output Output Output ➟ Input ➟ Input ➟ Input CAUTION • The tone curve cannot be adjusted manually in one of the color scan modes when ColorSync is selected because the color balance is adjusted automatically. • The tone curve cannot be adjusted for a black and white image because mid-tones are shown as either black or white. To adjust the brightness of a black and white image, use the threshold setting (p. 50). 44

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71

44
S T E P
3
The Relationship Between the Tone Curve
and Image Brightness
Tone curve values fall with a range of 0.01 to 10.00.
A value of 1 appears as a
straight line in the graph, and if the value is any value other than one, the line on
the graph will appear curved. The relationship between the shape of the curve and
image brightness is explained below.
Value = 1
Input and output and are equal
and the curve appears as a
straight line, and the input
image is displayed on the
screen without adjustment.
Value > 1
The data bends upward over
the range of input values from
shadows to highlights, making
the adjusted image brighter in
the display.
Value < 1
The data bends downward over
the range of input values from
shadows to highlights, making
the adjusted image darker in
the display.
CAUTION
The tone curve cannot be adjusted manually in one of the color scan
modes when ColorSync is selected because the color balance is adjusted
automatically.
The tone curve cannot be adjusted for a black and white image because
mid-tones are shown as either black or white. To adjust the brightness of
a black and white image, use the
threshold setting
(p. 50)
.
Output
Input
Output
Input
Output
Input