Radiological system employing phosphors of different densities

A radiographic recording system comprising, in combination, a front intensifying screen, a back intensifying screen and a double emulsion film element in operative contact disposed therebetween;

• said front intensifying screen comprises a front phosphor layer coated on a support, wherein said front phosphor is selected from the group consisting of:
• (1) BaSO.sub.4 activated with lead;
• (2) Y.sub.2 O.sub.3 activated with gadolinium, cerium, bismuth, lead or combinations of the elements chosen from gadolinium, cerium, bismuth and lead;
• (3) DP.sub.2 O.sub.7 wherein D is hafnium or zirconium;
• (4) GFCl activated with europium where G represents barium or partial substitution thereof by an alkali metal, trivalent metal;
• or combination thereof;
• (5) YOX activated with cerium, gadolinium, bismuth or lead where X is fluorine, chlorine, or bromine;
• (6) Y.sub.2 O.sub.2 S activated with bismuth, cerium, gadolinium, lead or combinations of the elements chosen from bismuth, cerium, gadolinium and lead;
• (7) BaSiO.sub.3 activated with lead;
• (8) YPO.sub.4 activated with gadolinium, indium or combinations of gadolinium and indium;
• (9) Ca.sub.2 ZrSi.sub.4 O.sub.12 activated with lead;
• (10) BaZnSiO.sub.2 activated with lead;
• and
• (11) combination of phosphors chosen from (1)-(10);
• said back intensifying screen comprises a back phosphor layer coated on a support, wherein said back phosphor is selected from the group consisting of:
• (a) YTaO.sub.4, unactivated or activated with niobium, thulium, gadolinium, terbium or combinations of the elements chosen from niobium, thulium, gadolinium, terbium;
• (b) LuTaO.sub.4, unactivated or activated with niobium, thulium, gadolinium, terbium or combinations of the elements chosen from niobium, thulium, gadolinium and terbium;
• (c) a solid solution of (a) and (b);
• (d) GdTaO.sub.4, activated with terbium;
• (e) a solid solution of at least two of (a), (b) and (d);
• (f) any of (a) to (e) wherein up to 45 mole percent of the yttrium, lutetium or gadolinium is replaced by lanthanum;
• (g) any of (a) to (f) wherein up to 15 mole percent the yttrium, lutetium or gadolinium is replaced by ytterbium;
• and
• (h) any of (a), (b) and (c) wherein up to 15 mole percent of the yttrium or lutetium is replace by gadolinium;
• (i) Mg.sub.4 Ta.sub.2-2x Nb.sub.2x O.sub.9 :
• MyNa.sub.y' wherein
• M is at least one of potassium, rubidium, cesium;
• x is 5.times.10.sup.-4 to 0.5;
• y is at least 2.times.10.sup.-3, and
• y+y' is less than 1.0;
• (j) hafnium zirconium germanate unactivated or activated with titanium;
• (k) Hf.sub.1-z Zr.sub.z M.sub.y Ti.sub.x E.sub.e O.sub.a wherein
• E represents at least one of germanium and silicon;
• e is in the range of from greater than 1.times.10.sup.-3 to 0.1;
• M represents at least one alkali metal;
• x is in the range of from 3.times.10.sup.-4 to 1.0;
• y is in the range of 1.times.10.sup.-4 to 1.0;
• z is in the range of from 4.times.10.sup.-4 to 0.3;
• and
• a is sufficient to balance the charge.
• (l) CaWO.sub.4 ;
• (m) hafnium zirconium oxide containing at least one alkali metal and activated with titanium, at least one rare earth element or a combination of titanium and at least one rare earth element;
• (n) Li.sub.2 Hf.sub.1-x-y-z Zr.sub.z Sn.sub.y Ti.sub.x L.sub.w O.sub.3
• where L is at least one rare earth;
• w+x+y collectively are 0 to 0.2;
• and
• z is up to 0.2;
• (o) LnOX activated with terbium, thulium, cerium, ytterbium, or bismuth wherein Ln is gadolinium or lanthanum and X is fluorine, chlorine, or bromine;
• (p) Ln.sub.2 O.sub.2 S activated with at least one rare earth element, where Ln is gadolinium, lanthanum or lutetium.