1. Radiographic projection of objects

2. Step wedge

3. Darkening curve of films exposition darkening linear part

4. darkening

5. darkbright human eyes Rtg. film Sensitivity to grey spectrumof the eyes and radiographic films

6. Hermann grid illusion

7. Mach Band effect

8. Koffka ring

10. Role of the background

11. Mach Band

17. Localization of defects

18. Role of the background

19. Projection of bone lesions

21. Localization of root apex

22. Apical transparenties

26. „God is good to endodontists” 90% of apical defects transparent Mainly localised at the apex Close to the cortical bone Background usualy bright

27. Disturbing factors Inclination Anatomic noise (anatomical landmarks) Size (too small) Expozition Film development

28. Anatomical landmarks/direction

30. Facts affect to image quality sharpness contrast projection

32. brightness-darkness

33. Projection of periodontium

34. Periodontium

35. Projection in the horizontal plain mesial distal orthoradial

36. Buccal object rule S ame L ingual O pposite B uccal

37. Parallaxis

38. Lokalized CT (CBCT)