In a message dated 98-04-09 11:45:04 EDT, you write:

Dear Kent,
 
 In the old analog system, particularly analog sound tape, frequency
 information was converted to magnetic patterns on the tape which mirrored
 the original signal.  But the information was nevertheless converted to a
 magnetic pattern, not a sound pattern.  With light, photographic film does
 the same thing, and converts photon energy to a chemical pattern that is an
 analog of the original signal.  In neither case is the original signal
 preserved, only its magnetic or chemical shadow.  If a particular frequency
 or wavelength of light indicative of atomic signature is present in the
 original signal, and if the magnetic or chemical medium can detect that
 signal, then it is recorded.  But if another kind of material gives off the
 same type of signal, the recording medium will not distinguish the two
 without filters.  Filters select for specific signals, and remove them from
 being recorded.  Then the original unfiltered record can be compared to the
 filtered one to see if that particular signal is present, and if it is,
 then some conclusion about the atomic source producing the signal can be
 made.
 
 But in the digital realm the signal is converted to a binary digital code,
 which is a further modification of the source signal.  The CCD chip can
 record various wavelengths of light, usually in the red, blue, and green
 wavelengths.  Some people and companies claim that you can perform spectral
 analysis with CCD data, but that is only possible if the CCD chip records
 that signal in the first place, and the electronics convert it to an
 accurate digital code for that signal.  But with the use of filters, all
 you have is a soup of information, the individual components of which are
 not separable beyond the RBG capability of the recording system.
 
 Now to answer your question:  The face image is a digital image, the
 digital data for which that has gone through various filters.  We do not
 know what those filters were or how they would alter the data.  Because as
 much as 70% of the gray scale is missing from the original strip, one could
 say that the data were heavily processed and filtered.  Without an
 unfiltered strip or data for comparision, we don't know what was there to
 begin with.  Consequently, without the filtered data separated and imaged
 separately, we will not be able to detect Cesium 157 or any other element. 
 That is, unless NASA were to tell us that when the original image was
 taken, a Cesium 157 spectrum filter was being used, and the image gray
 scale represents what the filter filtered out.
 
 Frankly, I think that the conspiracy buffs are acting like ignoramuses,
 being driven by their fears, hopes, and fantasies to make unwarranted
 accusations.  Just look at Hoagland's initial comments after seeing the
 squashed image of the face (on your webpage).  I am also suspicious that
 Parker may have added information that was not originally present in order
 to "save face" (pun intended) for NASA, after realizing that there would be
 a great outcry of "foul play" coming from those who were disappointed.  My
 reply: Their reactions were way too premature and immature. And as your
 website indicates, the shadow of the Viking "face" may be the telltale
 trace of that face-saving manipulation.  
 
 Yours truly,
 Bruce