This demonstration simulates the process of setting scanner exposure and its effect on the resultant image.  The top histogram represents the distribution of the source image tones.  The white area represents the sensitivity range of the scanner.  The bottom histogram represents the resultant scanned image.

1. Open the combo box list and select a hypothetical source image to be scanned (e.g. Low-key - 2).

2. Adjust exposure until the maximum number of tones is reached. Usually this reached when the specular highlights (the right-most edge of the source histogram) nears the right margin.

3. Applying a black-white point setting displays any possible discontinuities of the tonal scale due to this function.

The tonal gradient below the image histogram shows the actual tones in the image.  The wider the gradient, the more tones present in the image.  In addition, though the base of the histogram may span the entire frame, missing tones will result in a narrower gradient being displayed. 

Copyright 2002 - 2008,  Marginal Software.

Is your browser having difficulties loading the demo?  Go to Sun JVM to download and install the Java 2 Runtime Environment.

Note: your browser must be Java enabled to run this simulation.  

How to check Java permissions in Microsoft Internet Explorer:

1. Open Tools, Internet Options

2. Select Security tab; select Internet zone; press Custom Level button

3. In the Settings, Java permissions must be set to Medium safety or lower