Benefits
of the plugin

Illumine shadows without overexposing lights.
Darken lights without darkening shadows.
Reduce contrast by reducing the dynamic range.
Master all aspects of dynamic range like offset and white- and blackpoint stretching.

The Dynamic Range Compression plugin works with these image modes (Win and Mac):
8 & 16 bit / channel: RGB, Grayscale, Duotone, Lab, CMYK, Multichannel.

Brightness Editor
controls

This is the Dynamic Range plug-ins control panel. Click on the photo or the links to the right to see the plugin at full size. The filter has four groups of controls:

1. Range Compression - darks and lights
2. Graduated effect
3. Range adjustment - offset and black point
4. Overall effect and saturation

Example - The left image has its high dynamic range compressed in three degrees

The Dynamic range Compression plugin is indispensable for making high contrast photos look like what the scene really looked like when you took the picture. Original is leftmost.

What is HDR - High Dynamic Range - and why is it a problem?

High Dynamic Range (HDR) and its problems

A photo's dynamic range is the pictures span from its darkest value to its brightest value. If the darkest value is black and the brightest white, then the dynamic range is fully utilized. Most pictures don't cover the entire range and are offset from either white (most common) or black or perhaps both. This is not necessarily a problem as it can be a way to control the photos expressive power.

What is a problem, however, is the annoying fact that the camera or scanner - or the monitor - is not as sensitive to the entire dynamic range as the human vision is. In other words the human vision has a higher dynamic range. In a scene where the eye will perceive details in both the light and dark areas at the same time, the camera or scanner will only be able to capture one end while rendering the other as an underexposed or overexposed mass. With our filter you can correct that and restore the original impression.

What is High Dynamic Range Compression?

High Dynamic Range compression

... is also called High Dynamic Range expansion

"High dynamic range compression" is also sometimes called "high dynamic range enhancement", "high dynamic range expansion" or "high dynamic range extension" This is because if you want to expand the visible range, you have to compress the image data.

As you can see in the large example just below, the camera is not as sensitive to small variations in the dark range as the eye is, so we have to compress the dark values in order to reveal what the photo hides in the shades. Fortunately the camera is not blind, but does capture much information in the dark areas of the photo, so we can reconstruct what the eye perceived.

Since the photo already covers the entire dynamic range, we can't improve the image by overall brightening - that would overexpose the lights. Proper dynamic range compression stays within the photos given dynamic range and will compress either the darks or the lights. In this case we have made the given dark range cover a much wider dynamic range and have thus restored the original impression of the scene.

Example of full filter use when compressing shadows

High dynamic range compression of shadows

Example of full filter use when compressing highlights also

High dynamic range compression of highlights also

You will find that most of the discussions about correcting HDR, high dynamic range, images, is concerned with how to compress the shadows and expand visibility into the dark areas. However, images can improve considerably by compressing the highlight range.

In this case we lowered the offset a bit below black alert in order to darken the lights as much as possible before compression.

The Controls

Range compression

Range adjustment

Overall effect

First group lets you compress either shadows or hightlights.

Second group lets you change the outer limits of the density range. Here you can make the lights brighter and the darks darker. In other words you can move the histogram up or down (offset) or expand the histogram in either direction.

Third group lets you adjust saturation and also reduce the effect by mixing with the original.

Graduated effect

These controls are common for many of the Power Retouche plug-ins. Using graduated effect will cause the filter to apply it's filtering at full strength in one side of the image and then fade the effect out towards the other side. You can change direction by right clicking the preview. Midpoint will shift the balance between how large an area will be filtered at full strength and how much will have a faded out effect. Contrast will change the accelleration and spread of the fade-out.

In this example we applied a graduated effect towards the bottom, setting midpoint to the edge of the gray clouds. This retouch brought light into the underexposed foreground, bringing it forward, without altering the sunset.

Examples of what the controls do

Shadows %

Compression Factor

Highlights %

Color problem when compressing highlights

Other Controls

Offset

Black Alert

White Alert

Black Point

More control than levels adjustment

Compared to adjusting levels in Photoshop, you preserve more color information in the highlights with our method.

Shadow Depth

Shadow Threshold

Shadow Threshold is a pair with Shadow Depth. It sets the brightness value above which no shadow deepening should occur.

Output Adjustments

Overall Effect

Compressed high dynamic range images are made by combining several exposures of the same image. This slider lets you control the combination algorithm. This control is particularly useful when compressing with factors above 95%. One of the advantages of this is that it can preserve more detail-contrast in the mid tone range.

Saturation

This slider lets you adjust the color saturation. It is an implementation of the power retouche photographic saturation

Photo credits

All photos by courtesy of Charlie Bustamente