Selecting "Xtras/Adjust Color/Auto Levels" causes Fireworks to automatically adjust the tones in the image.

Manually adjust the tonal levels of your document by selecting Levels from the Adjust Color Menu. A dialog box will appear which contains a Histogram.

(Figure 8.14)

The histogram gives you a visual representation of the tonal distribution of the pixels in your document. Along the x-axis, the far left of the graph represents shadows, the far right indicates highlights, and the middle represents midtones. The y-axis indicates the number of pixels within each tonal range.

An image that has proper tonal balance would have a fairly flat histogram with no major spikes in any particular range. If your images levels don’t fit this profile you can use the Input Level sliders in the Level’s dialog box to adjust them. The sliders reflect the three ranges that can be adjusted with black as shadow, grey as midtone, and white as highlight.  {Click} on the Preview checkbox and adjust the sliders. Your image’s appearance should change as you move the sliders. When you are happy with the

appearance of your image {Click} OK.

You can also set the Shadow, Midtone, and Highlight levels manually by using the eyedroppers in the dialog box.  Again, there are three droppers with each representing a particular tonal range. Select the Shadow dropper and use it to select the darkest area of pixels in your document. Do the same with the others to select the points within their range. If you are happy with the results of your selections {Click} OK.

Adjust the contrast in your image by moving the Output Slider at the bottom of the Levels dialog box.

Selecting this option will literally invert the color of each pixel in your document.  Effectively your image is turned into a negative of itself.

Blur your bitmapped content by selecting "Xtras/Blur" from the menu. Selecting Blur and Blur More will apply a preset blur to your image that you can’t control.  Selecting Gaussian Blur will present you with a dialog box that allows you to control the amount of blurring that is applied to the image by moving a slider back and forth.

(Figure 8.15)

Operates in the same way as a blur except in this case you’re sharpening instead or blurring. You can take control of the amount of sharpening that you apply to an image by selecting Unsharp Mask. You’ll be presented with a dialog box with three sliders that you can adjust. 

Selecting "Other" from the "Xtras" menu will present you with two options. You can convert either a selected object or your entire image into an alpha channel by select "Convert to Alpha". The content becomes a Grayscale image with the Black sections being completely opaque and the white sections being completely transparent. The gray sections of the image become variably transparent depending on the density of tone in each pixel.

The second option under the "Other" Menu is "Apply Edges". Try it out.  It creates a rather interesting effect that’s difficult to describe.