At 09:07 PM 12/26/2004 -0500, you wrote: >Howard, > >I won't be able to do that for a while because of travel plans. What >does one need to make this kind of measurement, a spectrophotometer? Yes, a vis/uv spectrometer is what is needed. I do not have one available since I moved to New Mexico. That is why I thought of the Clemson Chemistry department. I will do some checking after school starts up in Santa Fe to see if one of the local schools may have the needed equipment. Will let you know, and if all else fails, will probably see you at APIS or at PhotoArts Santa Fe, July 8-17, 2005 (shameless commercial plug). ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.