An X-Ray Film

1. An X-Ray Film produce an X-ray film on a polyester basis total thickness ~ 700 m emulsion thickness ~150 m no haze no halo

2. From Task to Product the task beginning obtaining insight the mechanism the sub tasks the problems buy or make? the sub-products quantitative design dimensioning putting together integration final specifications the product

3. Structure of a Film gelatin with silver halogen anti-halo layer polyester base anti-halo to avoid internal reflections

4. Latent pictures taking a picture: metallic Ag: catalyst for conversion of whole crystal. 4..5 atoms of Ag are sufficient size of the crystals  sensitivity of film

5. The Crystal (1) perfect crystal insensitive to light we need crystal defects simplifies production!

6. The Crystal (2)Sensibilisation strange ions (e.g. S) at surface: chemical sensibilisation dislocations: mechanical sensibilisation

7. X-ray films for medical applications high energy radiation simple sensibilisation low radiation dose large crystals crystal size distribution determines contrast of film

8. Sensitivity emulsion crystal size (m) ultra fine grain pan films high speed films medical X-ray 0.03 0.7 2.0 2.5 sideline:

9. Scheme (1) silver halogen gelatine emulsifying additives sensibilisation polyester basis anti-halo film hardening packaging drying cutting

10. Gelatine function: manufacturing: disperse AgBr clean and break bones monitor crystal growth remove inorganic material (3 days in dilute HCl) control light sensitivity wash with water + NaOH bromium acceptor convert ossene to collagen swelling in water (100 days in a CaCO3 solution) (10-12 < D < 10-9 m s-1) Conclusion: Buy!

11. Scheme (2) silver halogen gelatin buy make emulsion additives separation which? sensibilise how? polyester base anti-halo make buy film coating harden how? drying packaging cutting

12. Emulsification (1) - emulsification precipitation of AgBr crystals light - ripening recrystallization for crystal size - washing removing of byproducts - sensibilisation sensitivity for appropriate photons dark - coating including viscosity regulation crystallization yields: defect-free crystals (insensitive to light) specific size distribution (important for contrast)

13. Emulsification (2) AgNO3 add AgNO3 and stir AgNO3 + KBr  AgBr +KNO3 precipitate gelatin-AgBr ‘emulsion’ heat without stirring large crystals grow at the expense of small ones KBr + gelatin wash out KNO3 additives

14. Emulsification (3)Adjusting Crystal Size sensitivity and contrast determined by mixing time ripening time small initial crystal growth, long ripening time: uniform crystals, long process time, high contrast large initial crystal growth, short ripening time: less uniform crystals, short process time, low contrast

15. Emulsification (4)Example 1 400 mL water 20 g gelatin mixing time minutes crystal surface m2 13 g KBr 0.4 g KCl 0.14 0.28 0.50 0.82 1.47 2.25 0.5 4.5 10 20 43 55 2 400 mL water 20 g gelatin 20 g AgNO3

16. Precipitation + Additives Precipitator: - alcohol or recovery necessary - ammonium sulfate Kodak patent Additive for biological conservation: OH p-chloro-m-cresol (0.1 % w) or phenol (5 % w) CH3 Cl

17. N X X- N + Sensibilisation 2) spectral: 1) chemical: light sensitivity wave length (color) sensitivity spectral sensibilisation: red, orange etc.:  large,   small,  h small build in electron donors such as mercianins: + h  for X-rays:  small,   large,  h large: only chemical sensibilisation.

18. Sensibilisation (2) high [S] low [S] crystal defects sensitivity increasing sensitivity Na2S2O3 addition Ag2S at surface crystal defects haze ripening time

19. The Film emulsion anti-halo polyester make the polyester basis apply the coatings

20. Processes coating calendering adjusting the calendar fluid requirements avoiding thermal damage coating thickness

21. Specifications Product (customer specifications) 500 m thickness of the base 100 m anti halo 150 m emulsion Prepolymer specifications (data sheet of supplier) viscosity 2103 Pa s density 1300 kg m-3 specific heat 2200 J kg-1 K-1 Machine specifications (were still available) diameter of the drums 0.5 m motor power (effective) 5 kW length of the drums 1 m

22. In the Calendar (1) H d0 no flow in the z-direction viscous forces dominate

23. In the Calender (2) for the important regime so back to nearly parallel thin films……...

24. Thin Film Theory (1) pinch profile pinch equation:

25. Thin Film Theory (2) remember detachment

26. Solution for a Calender flow 0 maximum pressure 1 at 2 point of detachment 1 force exerted by roll 3 2 power to drive rolls 4

27. Solution for a Calender (2) For our film base:

28. Coating film coating roll coating kiss coating low viscosity simple accurate, thin knife coating curtain coating robust fast, thin

29. Modern Multi-layer Coating emulsion filters anti halo base (table coating of color film)

30. dy U yz y vx Emulsion Thickness (1) x so

31. Emulsion Thickness (2) boundary conditions and empirical constant

32. Emulsion Thickness (3) adjust coating speed to production speed: anti halo layer: emulsion:

33. Hardening (Cross-Linking) K Al (SO4)2 function: mechanical protection scratching chemical protection finger prints making emulsion insoluble developing

34. AgNO3 vacuum rollers KBr alcohol additives drying precipitation anti foam (nonyl) Na2S2O3 anti halo buffer drying hardening K Al (SO4)2