The main toolbar


The main toolbar allows you to perform several common operations common to the display of the image and bring up other image windows.  It consists, from left to right, of:
The W icon stands for Windows and clicking on it will list all possible windows that can be created.   Currently, these include:
The Channel display tells you what channel you are currently viewing (Color in the above picture).
The usual channels can be one of R,G,B,A and Lumma or Alpha Overlayed on top of RGB.

However, for image formats that support it like OpenEXR or Photoshop's PSD, it can also list all layers that are in the image.

The Gain control allows you to change the display gain of the image being displayed.
The F-Stop control is another way to control gain. It works in F-Stops, which is a common method used in photography and film to adjust a camera exposure.
The Normalization button allows you to normalize the image within the 0 and 1 range.  Its most common use is for properly viewing Z-Depth channels or shadow maps.
The Gamma control allows you to modify the display gamma.
The Field control allows you to display the image as a full frame or as video fields.
The 1:1 button allows you to toggle on and off a compensation for an image's pixel ratio.
The LUT button allows you to toggle the 3D LUT color correction for emulation of other media on your monitor.

The main toolbar can be toggled on and off by using the F1 hotkey.