You can adjust the timing of individual frames by selecting "Properties…" from the Frames Panel Pop Out Menu.  A small dialog box will appear prompting you to change the timing of the individual frame.  Fireworks measures animation time in hundredths of seconds with the default timing set at 20/100th’s of a second.  This default is reflected in the initial value set in the textfield of the dialog box and the timing listed to the right of each frame label.  You can export your timing settings when you create your final product by {Clicking} on the "Include when Exporting" checkbox.

(Figure 11.5)

Adjusting the timing of individual frames can be very useful if you want to create motion that doesn’t seem mechanical.  You may, for instance, want to fade in a block of text over a period of two seconds.  At 20/100ths of a second you would end up with 10 frames of animation, all playing at exactly the same rate.  To give the animation some character you might want to adjust the speed of the first frame to 40/100ths of a second, make the second frame 35/100ths of a second, 30/100ths for the third, and so on until you have 10 frames that play at different speeds.  If you time your frames correctly they will still play out over a 2 second duration and the graphic will fade up gradually at a variable rate.