# How to calculate the ( rtn gtn btn ) values of the material type glass ?

Hi Greg,

an intuituve description!
The results also look like right.

Nevertheless I define how I have proceeded, because there is a step that
could be wrong.

From the hole transmitance spectrum of each glass sample I have just

taken the transmittance values at this wavelengths you said and then
calculated its tn

#glass sample 01

Rot=700nm Tn=40.8 rtn= 18.093
Green=546 Tn=48.13 gtn= 18.813
Blue=436 Tn=42.87 btn= 18.317

void glass smpl_01
0
0
3 0.18093 0.18813 0.18317

And this would be the hole material description of this transparent
glass, als just one layer glass, 10mm thick

Thanks again,

Marina

Hi Marina,

The tn formula assumes your Tn values are between 0 and 1, not 0 and 100% -- your results should be:

void glass smpl_01
0
3 0.4449 0.5248 0.4675

Good that you checked!
-Greg

ยทยทยท

From: marina aviles olmos <marina.aviles@gmail.com>
Date: March 17, 2009 9:02:44 AM PDT

Hi Greg,

an intuituve description!
The results also look like right.

Nevertheless I define how I have proceeded, because there is a step that
could be wrong.

From the hole transmitance spectrum of each glass sample I have just

taken the transmittance values at this wavelengths you said and then
calculated its tn

#glass sample 01

Rot=700nm Tn=40.8 rtn= 18.093
Green=546 Tn=48.13 gtn= 18.813
Blue=436 Tn=42.87 btn= 18.317

void glass smpl_01
0
3 0.18093 0.18813 0.18317

And this would be the hole material description of this transparent
glass, als just one layer glass, 10mm thick

Thanks again,

Marina