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5. Define the counting frame size

Procedure

Counting Frame Display

• Force the counting frame to be square: When selected, it is implemented as you adjust the size.
• Snap to increments of: Use if you want the size of the counting frame size to be rounded; a counting frame size set as a whole number is easier to remember and to apply to future experiments.

Counting Frame Size

In subsequent steps, you will need to determine if the objects of interest (e.g., cell cross sections) are present or absent in the reference and in the lookup sections.

Size the counting frame to fit about 5 objects of interest.

1. Choose a unique identifying point that only comes into focus once for your cell (e.g., cell top, nucleus top, nucleolus).
2. Adjust the counting frame until it is approximately large enough for 1 to 5 objects.

 Some counting frames may have 0 objects, or more than 5—this is completely acceptable.
The reason for so few cells per counting frame is to minimize user error and fatigue. As you focus through the tissue to mark cells, it may be easy to lose track if you try to observe too many cells, especially in dense populations.

Moving the counting frame

To move the counting frame’s location on the screen, hover the cursor over the counting frame and drag the frame.

• Place the counting frame in the center of the screen.
• Keep an area outside of the counting frame large enough to clearly distinguish objects on the edge of the counting frame.
• The tails of the counting frame must be visible.