BD FACSDiva™ software gives you a choice of displaying your data in a 4 or 5 decade log scale. When you choose to display FACSDiva data in log in FCS Express, it defaults to display 5 decade log. However, you can easily change your settings to display 4 decade log.

Right click on the plot and select Format. Set the resolution options (found in Dot Options->Binned Dot Specific Options) as shown in the image below. Make sure to set both the X- and Y- axis.

An example of the same data shown on biexponential and 4 decade log

	Biexponential scaling	4 decade log scaling

Notice in the data above that there is quite a lot of data below channel 26 (the lowest channel  included on the 4 decade log plot). The include out of range values in gates and quads allows you to choose whether events below the axis are included in gates and quads drawn on the log plot.

	A	B

	C

Gate 1 was drawn on a 4 decade log plot with the include out of range values in gates and quads checked (A, above). The plot was then changed to show biexponential scaling (B, above), which shows all the data. Note that there are red cells to the left and below the border of the gate. They are colored red because they are considered to be part of Gate 1, since the plot upon which gate 1 was drawn had include out of range values in gates and quads checked.  If Gate 1 was drawn on a plot with include out of range values in gates and quads unchecked, the events below the axis would not be included as part of Gate 1, as shown in C. Quadrants statistics are similarly affected. In the left panel below, the quadrant statistics add up to 100%, since the events below and to the left of the plot are being included as part of the quadrant calculations. In the panel on the right, the quadrant statistics do not add up to 100% because cells with values below 26 (the lowest value being displayed on the plot) are not included in the quadrant statistics.

	Quads on 4 decade plot with include out of range values in gates and quads checked.	Quads on 4 decade plot with include out of range values in gates and quads unchecked.

Please note if you set the resolution options as described in the first figure above, the Axis Ranges can all be set to Automatic, as in the figure below. This will need to be set for both X and Y axes.

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