Phoretix 1D Rolling Ball Size Converter
Upgrading your lab’s 1D gel analysis workflows to the latest version of our software? You may notice an important change in how background subtraction is parameterized. We created this free Phoretix 1D rolling ball size converter to help researchers easily translate legacy, pixel-based radius measurements into the new, standardized percentage format.
Whether you are updating strict laboratory SOPs or simply want to ensure your historical quantitative data remains perfectly reproducible, this tool takes the guesswork out of your pixel-to-percentage lane length calculations.
To understand the necessity of this shift toward standardization, it is helpful to visualize the underlying mathematics:
As illustrated in the “Rolling Ball Background Subtraction Principle” diagram, the process works by virtually “rolling” a sphere of a defined size underneath your raw densitometry trace. The sphere cannot enter sharp peaks but can follow broader background variations, effectively tracing a baseline path. This creates a reliable mathematical model of the background noise which is then subtracted from the raw data.
Why the change to percentage-based background subtraction?
In recent updates to Phoretix 1D, we transitioned the rolling ball radius measurement from absolute pixels to a percentage of the total lane length. We made this change to significantly improve the reproducibility and standardization of your analysis.
Absolute pixel sizes can vary dramatically depending on your scanner’s resolution (DPI) or how an image is cropped, which can lead to inconsistent background subtraction across different experiments. By defining the rolling ball size as a percentage, your background subtraction remains perfectly proportional and consistent, regardless of the raw image dimensions. This also future proofs the software for future increases in the resolution of scanners meaning the software works better, for longer, regardless of hardware upgrades in the future.
If you have existing Standard Operating Procedures (SOPs) that rely on legacy pixel measurements, simply use the calculator below to quickly convert them into the new, standardized percentage format for your current workflows.
Pixel to Percentage Calculator
To use the above tool, simply enter your “old” rolling ball size, the length of your lanes (our Phoretix 1D software tells you this number under the “Length” measurement) and it will give you the new percentage to use. Simply click the copy to clipboard button and paste it straight into Phoretix 1D!