Keep in mind that any relatively inexpensive emissive instrument is going to have problems in reading extreme low light, that's the hallmark of inexpensive. I was once told by Danny Rich that, what we're asking is for the instrument to read practically no light -- very difficult to detect few photons reliably. So, personally, anything below 1 cd/m2 I tend to take with a grain of salt. BTW, for those who are interested in the EyeOnePros, I was told that if they are held about 5 cm off the screen, a) they won't exhibit any thermal drift whatsoever and b) the readings will not be significantly different from those obtained by contact measurements. But thank's for your code modification for the Spyder3. Roger > Hello again! > > As I wrote in the last post I have found a possible bug in Spyd2.c. > Spyder3 has problems with reading a very dark patch and can sometimes > return garbage: > To confirm the bug try reading a completely black patch a few (10?) > times with spotread and you will see that the results are something > like (for X axis):0.2, 0.19,0.2, 0.17 [so far OK], 0.01 [Stupid > reading!], > 0.2, 0.19 [etc.]. The problem is IMHO caused by too small reading time > in spyd2.c. When I