Image Adjustments

 

Rotation

These buttons rotate the image. Occasionally an image file may be up-side-down, often when a film has been scanned onto a CD by a photo-developer.

Rotate 90° Clockwise          

Rotate 90° Anti-Clockwise     

Invert Image                       

Reload Original Image          

Rotate by Degree            (Adjustment menu only)

 

Levels - Brightness, Contrast and Saturation   

Also found under the Adjustments Menu.

A separate window opens with a lower-resolution copy to speed up previewing changes.

Initially, the process operates in RGB mode where all three colours are adjusted together, or you can select red, green or blue to adjust each colour independently, as shown in the example above.

Top-right is a histogram which shows the distribution of pixels through the intensity range from minimum brightness (or black) on the left to maximum (or white) on the right.

Basically, adjust the brightness and contrast sliders so there is a spread right across histogram. The height of the peaks is not important. There is also a readout of the brightness at any point on the image. Point at a bright white part of the image and it should read close to 255,255,255, and a black part close to 0,0,0. Adjust brightness and Contrast to achieve this.

Use Shadows, Midtones and Highlights to brighten or darken one of those regions, if necessary adjusting all three to keep a smooth transition from one to another. The line through the histogram indicates the before / after transfer characteristic. The 'Link' button makes the Midtone slider control the highlights and shadows as well, making an easy way to bend the transfer line.

Use Saturation to alter the colour intensity, right down to Black & White if necessary. Note extreme saturation changes eat into the range of other adjustments, so if necessary make saturation and levels changes separately.

Mid-tone Contrast

This option causes the Highlights, Midtone and Shadows controls to be linked to the midtone control making mid-tone adjustment easier.

Show Clipping

When this option is ticked areas of peak white are artificially coloured red and areas of black are coloured blue. This makes it easy to see when the limits are reached. It is not always appropriate to avoid clipping totally, there may be specular highlights - small bright white areas - on shiny objects.

Keep Settings

Tick this option to keep your settings for the next time you the open Levels adjustment. The settings are lost when the program is closed.

 

Click OK to keep the changes or Cancel to forget them. Reset puts the sliders all back to zero (no change).

If you make adjustments then change your mind, use the reload button    to start again.