Hi Graeme, I solved my problem on a quite strange way simply by connecting another Eye One and calibrating it. Afterwards I reconnected the previous model. It works fine now. Maybe you have an idea? Regards Vladimir -- Gesendet von meinem Palm Pre Graeme Gill <graeme@xxxxxxxxxxxxx> schrieb am 21.04.2010 03:17: Vladimir Gajic wrote: > "Strip failed due to missread(Dark calibration is inconsistent) > Hit Esc to give up, and any other key to retry: " Before each reflective measurement there is a dark calibration. That means that while the instrument is held on the paper, before its light is turned on, it measures its sensor value, and uses that as its zero reference. If the value is not constant during that time, it returns the error you are seeing. This could be a fault in the hardware or bug in driver, but first you need to make sure that the instrument is being used with the chart correctly. Make sure that you aren't operating in a brightly lit environment. Make sure that the chart is on a flat, firm surface, and that the instrument is flat on the chart (ie. that it's not at a slight angle due to different thicknesses of paper under each end of it), and that light isn't leaking in between the paper and the instrument. If you are using a guide to measure a strip, make sure there is no build up of ink on the guide, and that the instrument is properly fitted to the guide, and isn't sitting on a lip (I find this often happens to me when I'm using the spot reading guide). Graeme Gill.