| 摘要 |
<p>Pictures and background areas are stabilised using a soln. of a stabilising amt. of a substance of formula:- M3-v-w(H)wS1+xo3+2x (in which x is 0 or 2; M is a cation; v is a valency of the cation; w = 0 if v = 2 and w = 0 or 1 if v = 1). The photosensitive combination consists of a) an organic halogen cpd. which forms free radicals or ions when exposed with light of suitable wavelength and contains at least one halogen, e.g. Cl. Br and I, bound to C atom which is bound to not more than one H atom; and b) an aromatic cpd. contg. N, which can form a colour with the halogen cpd. in actinic light. These cpds. are dispersed in a solid, film-forming hydrophilic binder. These photographs can be used as masters in diazo and other reprodn. processes. Treatment prevents darkening in background areas and allows material to be exposed repeatedly with light of any wavelength.</p> |
