Bio-Rad Image Lab™ Software - Manual (Page 137)

Lane and Bands Tools
User Guide | 137
You can also change the lane width by specifying the size of the lanes. Click the
Width button, enter a number (in mm) in the box, and click Apply.
Note: You might notice that the number in the box changes after you click
Apply. For example, you enter 5.75 and the number changes to 5.71. The
image is composed of pixels and the software can draw a boundary only in
the lane between pixels. If the number you specify would cause the
boundary to fall anywhere on the pixels, Image Lab moves the boundary so
that it falls between two pixels and updates the number accordingly.
Lane Background Subtraction
To perform lane-based background subtraction
 Select Enable Subtraction in the Background Subtraction field. Use the Lane
Profile view to see the subtracted lane background.
Disk Size — specifies the size of a hypothetical rolling disk (between 0.5 and
99.5 mm in 0.5 mm increments) that removes background levels along the length of
the lane. The size of the disk determines how closely the background level follows
the intensity profile.
A large disk follows the profile trace less closely, touching fewer points along the
trace and removing less background. A smaller disk more closely follows the profile
trace, removing more background.
A disk radius that is too large will result in poor background removal. A disk radius
that is too small might subtract actual data. For most samples, a size of <10 mm is
usually appropriate. You can perform this task several times until you are satisfied
with the amount of background removed. Use the Lane Profile tool to evaluate the
appropriate disk size for background subtraction.
Apply to selected Lane — applies the specified level of background subtraction
only to the selected lane. This option enables you to set different background
subtraction levels for each lane.