Olindo, Forgive me if I'm confused, but are you trying to convert values (number of cells) for each channel, or convert channel numbers (x-axis, 0 to 1023) to log values (1 to 10000)? To do the later we use the same formula you found in the manual. Here's our version: log value = 10^ [channel number / full scale ch number) * decade range] On our Elite full scale ch number = 1024 and decade range is 4, which is where they get the 256 scale factor. That gives you a range of 1-10000, while the original scale values the Elite provided were 0.1-1000, but I just multiply each by 0.1. I don't know whether this helps you at all--I had to do this to get single parameter histos to plot correctly in Excel. Steve +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Steve G. Hilliard (706) 542-9474 University of Georgia Cell Analysis Facility flowman@uga.edu http://floweb.cb.uga.edu/ On Mon, 5 Jun 2000, Olindo Assis wrote: > > Dear Flowers, > > It was clear for me, after I read the answers to my question about mean > fluorescence channel analysis that most people suggested to analyze the data > using the original number "mean" from the Log scale (10^0 - 10^4). > > However, I had analyzed most of my data after conversion of original data to > channel values. Then, I start to have a problem because I did not want to go > back and reanalyze all data since we have over 2,000 files to be analyzed. > > Therefore I was looking for a formula (mathematical expression) to convert > the data back to Log values. Actually I found it on the CellQuest BD manual > on chapter 6 "histograms". They say that to convert channel values to Log > and vice-versa we just need to apply the following expression: > > Log values = 10^(channel value/*scale factor) > > where scale factor is 256 for a 0-1024 scale and 64 for a 0-256 scale. > >
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