ORIS PDF Tuner Version 4.4.8 User Manual - image2output - Support

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Gradation Changes and Tone Value Corrections
Correcting Tone Values
3. To increase image contrast, use the horizontal controls on the bottom.
The triangle above LOW increases the shadows. As you move it to
the opposite side, it darkens increasingly lighter pixels.
The triangle above HIGH increases the highlights. The triangle
in the center adjusts the midtones. Move it to the right or left to lighten
or darken the midtone areas.
You can also move the lines starting from these triangles, which is often
more convenient. Place the cursor anywhere on a line in order to
move it.
To make very precise changes, you can enter the values into the
LOW, MID and HIGH box. The value range is 0–255 for shadows and
highlights and 0.1–9.82 for midtones. The LOW value at 0, MID at 1
and HIGH at 255 represent the image’s current settings.
See also About Shadow and Highlight Settings below.
4. To reduce image contrast, use the vertical controls on the left.
Move the triangles or the line starting from the respective triangles.
You can also enter the values into the MAX or MIN box. Depending on
the image type (RGB or CMYK), the highlights or shadows are reduced.
See also About Tone Range Settings below.
5. If you want to reverse all changes, click RESET. This affects all color
separations.
6. When finished, press RETURN/ENTER or click .
Note:
Do not select the MODE function as switching to another mode will cancel
all changes.
About Shadow and Highlight Settings
Example 1
Suppose an RGB image contains pixels that cover the entire 0-to-255
scale and you want to increase the image contrast. If you set the highlight
value (HIGH) to 206, pixels with a tone value of 206 and higher are
mapped to 255, and pixels with tonal values lower than 206 are mapped
to corresponding higher values. This lightens the image and increases
the contrast in the highlight areas.
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