Brightness Controls

The four ColorBender Brightness controls are:

• Brightness
• Contrast
• Shadow Brightness
• Highlight Brightness

These operations are fundamentally different than similar controls in other applications. The differences are that ColorBender

• does not clip.
• does not shift color.
• does not alter the white point or black point.
• maintains consistency between all control combinations.
• maintains balance between neutral changes and color tone changes.

These differences are somewhat technical and are discussed below in greater detail along with examples. But the effect of the ColorBender Technology is that controls work better over a broader range of settings. Images can be adjusted easier and faster and useable results obtained more often.

Example of Simple Brightness Adjustment

This image was corrected by simply selecting "brightness" from the popup menu and adjusting the slider. The original image was taken with a digital camera with no flash and insufficient light.

 
original image                                       brightened image

 

Example of Selective Shadow Adjustment

The following image needed the inside region shadows to be brightened. On the adjustment panel, the center region is selected, the shadow operation selected and the slider set to to 81. The results are shown on the right

 
                original                                                                  center region shadow boost

   control settings for the above results

Processing this image took 2 clicks to select the inside region, a click/select to set the Shadow Operation and a slider adjustment.

 

Example of Selective Brightness Adjustment

The following image needed cropping and selective brightness adjustment. The cropping took two mouse drag operations, setting the center middle and center top regions took 3 clicks, selecting brightness took a click/select and the slider was adjusted for the desired brightness.

Brightness Control Consistency

The visual effects of brightness, contrast, shadows and highlights are interrelated. With a little thought we note the following.

• If Shadow brightness is increased, then overall brightness is increased and overall contrast is decreased
• If Shadow brightness is decreased, then overall brightness is decreased and overall contrast is increased
• If Highlight brightness is increased, then overall brightness is increased and overall contrast is increased
• If Highlight brightness is decreased, then overall brightness is decreased and overall contrast is decreased.

Thus, for various combinations of brightness and contrast we would expect the following effects on Highlights and Shadows.

• To brighten highlights while preserving shadows, increase brightness and decrease contrast.
• To darken highlights while preserving shadows, decrease brightness and increase contrast.
• To brighten shadows while preserving highlights, increase brightness and increase contrast.
• To darken shadows while preserving highlights, decrease brightness and decrease contrast.

For ColorBender, these relationships hold exactly. (If, for example, you increase brightness to +60, then the shadow value and highlight value will be automatically adjusted to +60 each.)

The following 9 images give the results from the settings of Brightness = (-60, 0, +60) and Contrast = (-60, 0, +60). Although ColorBender has Highlight and Shadow adjustments to give easier control, the results are exactly the same as combining Brightness and Contrast adjustments.

  
bright highlights (ColorBender)                    high brightness (ColorBender)                               bright shadows (ColorBender)
  
low contrast (ColorBender)                                       original                                                         high contrast (ColorBender)
  
dark shadows (ColorBender)                           low brightness (ColorBender)                                       dark highlights (ColorBender)

For comparison, the following images were processed in iPhoto with similar settings.

  
bright highlights (iPhoto)                                   high brightness (iPhoto)                                       bright shadows (iPhoto)
  
low contrast (iPhoto)                                                               original                                                          high contrast (iPhoto)
  
dark shadows (iPhoto)                                                 low brightness (iPhoto)                                                 dark highlights (iPhoto)

 

ColorBender Technical Differences

Above, the ColorBender Differences were listed as follows:

• Does not clip
• Does not shift color
• Does not alter the white point or black point
• Maintains consistency between all control combinations
• Maintains balance between neutral changes and color tone changes

The nine ColorBender images and the nine iPhoto images in this section can be used to illustrate these differences and why they are important.

• Bright clipping can be seen in the clouds on the top row on the iPhoto images. The corresponding ColorBender images maintain the cloud brightness structure.
• Dark clipping can be seen in the vine in the iPhoto dark highlights (bottom right), but the dark structure is preserved in the corresponding ColorBender image.
• Color shifting can be seen in the sky on the top row on the iPhoto images. The corresponding ColorBender images do not shift the color (hue).
• The whitest point in the image is the cloud behind the bottom of the tree trunk. Notice how this is different on each of the iPhoto results, but is the same on all of the ColorBender results. Comparing the low brightness example (bottom center) shows that although both have similar overall brightness, the ColorBender results has much better visual contrast.
• The blackest point in the image is the vine located to the right and in front of the tree. As before, notice that this is similar on all the ColorBender images and is much different on the iPhoto images.
• As an example of consistency compare the dark highlights (bottom right) to low brightness (bottom center) and high contrast (middle right). For ColorBender, both brightness adjustments and contrast adjustments produce corresponding changes. For iPhoto, the contrast adjustment has very little visual change compared to a brightness adjustment.
• An example of maintaining proper balance between neutrals and color tone is the bright highlights (top left). For ColorBender, the tree maintains good color whereas for iPhoto, the tree is washed out.

ColorBender 1.1 is a Universal Application that runs on Mac OS X 10.4 or later

© 4G Color 2005, 2006, 2007 all rights reserved, Website updated March 7, 2007