A sensitive spectrophotometric method for the determination of silver is described. The reaction involves a silver-enhanced reduction of 2,3,5-triphenyl-2H-tetrazolium chloride by semicarbazide hydrochloride to yield a pink-colored product with maximum absorption at 510 nm. Beer's law is obeyed in the concentration range of 0.02-0.34 microg cm(-3) of silver, and the molar absorptivity is 4.51 x...

The predominant way of preserving digital images is in their current form. Doing so for the long term, however, will require format migration to avoid the problem of hardware and software obsolescence. An alternative approach is to record digital image information on media with recognized longevity, in a human-readable format. As an investigation of practical archiving in this way, we demonstra...

The question of radiometric resolution is an important one in connection with the introduction of digital systems. The number of available bits is generally given with the note that the achieved radiometric resolution is much superior to that of photographic emulsions. In this comparison it is usually overlooked that film records densities, i.e. logarithmic values, while CCDs record transmittan...