sample 57
peacock feather

this is a special sample because it shows very nice color 
changes (that's why we measure it). It's quite dark so the 
aperture is open wider than ever before

aperture: 1 tick before 4
zoom: maximum since sample area is small
parameters; z=330 p=19 l=163

i used double sided tape to put the feather on black cardboard. 
at specular positions this tape is very bright around the sample

Since the sample is not homogeneous at all the normal 
calibration procedure makes no sense. I will do something else.
the sample consists of 4 areas. area1 is the kidney sized 
centre. Area 2 is around area 1 forming an ellipse together. 
area 3 is a wider ellipse around that. area 4 are the feathers 
at the outer side.

i'll put the sample at 45 degrees (position 2) and measure each 
area 1 to 4 with th photometer at 45, 67.5 90 and 112.5. In 
this way the color changes are apparent and we will have 
spectra of it. The normal calibration procedure shows no 
color changes. names of the files are p2-1,2,3,4 for position 2 
etc.

Next day (february 22) i continue with measurements

centering on holder by zooming out