Dave, I did some calculations based on some formulas provided here:
http://dsp.stackexchange.com/questions/8949/how-do-i-calculate-the-color-temperature-of-the-light-source-illuminating-an-ima I set up a spreadsheet to do the calculations, and pulled the RGB values with a graphics editor (Gimp). The hottest spot I could find according to those formulas was 1792C. This was based on the picture taken in the dark. Given that it is obvious that there are temperature variation across the tube, it does not seem unreasonable for 1400C average. The wire coming in the left side calculates to 2014C. Best, Jack On Sun, Oct 19, 2014 at 1:09 AM, David Roberson <dlrober...@aol.com> wrote: > I looked at that reference and went away about as confused as ever. Did > you look at the two references that I found? I think it is important for > us to follow up on this issue since it seems to be one that will not go > away. Do metals appear differently than the materials that Mizuno was > viewing? > > I found the view of the casting holes to be particularly interesting. > They resemble a black body by being deep and surrounded by hot material. > The color within these holes is very consistent from hole to hole and is > very orange. The other reference I found also showed orange as the > expected color. Two separate references should offer strong support for a > concept. > > Please take time to look at the references I have listed and I suspect you > might change your position. Keep in mind that what I found tends to > support what the testers observed. > > Dave > > > > -----Original Message----- > From: Jed Rothwell <jedrothw...@gmail.com> > To: vortex-l <vortex-l@eskimo.com> > Sent: Sun, Oct 19, 2014 1:57 am > Subject: Re: [Vo]:Color Temperature > > David Roberson <dlrober...@aol.com> wrote: > > >> Why would you expect the device to look white hot when a known metal >> casting looks orange hot at approximately the same temperature? What am I >> missing? >> > > I think you are wrong. Mizuno and one other person with experience > working with glass told me that 1300 deg C incandescence is white. That is > what this and other references show: > > > http://en.wikipedia.org/wiki/Incandescence#mediaviewer/File:Incandescence_Color.jpg > > Incandescence in all materials including solids and liquids has about > the same color. The color is independent of the material. > > Mizuno said materials at 1300 deg C are so bright, they will hurt your > eyes if you look at them. You need a welder's mask. > > As noted, we do not known when the photo was taken. I would say the > temperature is 800 to 900 deg C. That is more than the calibration > temperature. Maybe this was at the beginning of the test, before excess > heat turned on. I have the impression from the graphs that it turns on > quickly, so I doubt that is the case. > > If the authors do not address this question and tell us what color it > was, after a while I am going assume they made a mistake, and I am going to > ignore this test. > > - Jed > >
