Am 25.10.2010 22:22, schrieb Graeme Gill: > Whether that is of any significance, depends on your context. If it is > of no consequence to you, then I guess purchasing an instrument with 1 > nm resolution is not on your agenda :-) [Note that I currently have no > means of verifying whether the above differences represent an > improvement in accuracy of not.] Hi Graeme, looking at your laser pointer spectral plots it seems that the FWHM of the instrument's optical system is still the limiting factor [hard to tell exactly from the diagram - but I'd guess about 20nm ? - assuming of course that the laser is really monochromatic] The benefit of higher sampling resolution is of course limited if the bandwidth cannot be reduced as well. Theoretically the higher sampling resolution should offer an opportunity do deconvolve to a smaller effective bandwidth, but in practice a stronger deconvolution is limited either, by a too bad S/N ratio. Certainly, as we see, high-res mode does reduce the effective FWHM, but obviously it can't reduce the effective BW by the same factor as the sampling resolution is increased. So I'd still expect a noticeable improvement from an instrument which reports not just with 1nm resolution, but also *with 1nm FWHM*. According to the literature, 20nm BW is too much for accurate measurement of narrow-band light spectra, the literature rather suggests to use a BW of 5nm or less (and a corresponding resolution too, of course). To get a feeling for the impact, it's quite easy to simulate how the effective spectrum locus moves in chromaticity space, when monochrome spectra are "broadened" to a triangle or Gaussian with say 5nm, 10nm, 20nm, etc. FWHM [see http://tinyurl.com/ykrms2], and it should be easy as well to compute the corresponding colorimetric errors. Regards, Gerhard