And we continue with

1. And we continue with the hows and whys of analogue soundtracks, from conventional silver tracks over high magenta up to the final dye tracks. ab

2. We will talk about the production process of an analogue soundtrack. Starting with the exposure of a sound negative. ST8D & ST9 And ending with a soundtrack on a positive print film. CP20 ab

3. Every exposure starts with a light source. In a sound camera different light sources are used. For example in a WESTREX camera, Red LEDs for SDDS Green LEDs for SRD and DTS A white incandescent lamp for SR Let us therefore have a look at the performance of an incandescent lamp. ab

4. Every object at a temperature above 0 °K (-273°C) emits energy. Energy output of an incandescent lamp depends upon colour temperature. ab

5. What happens at different colour temperatures ? Wien’s displacement law What about the spectral performance of an FDT 12V 100W lamp, used in a Westrex sound camera ? ab

6. Light source to expose the sound negative in a Westrex camera. ab

7. What happens during the exposure of ST9 ? Sensitometry of sound negative The spectral sensitivity of the film The spectral output of the lamp x = Resulting actinic energy 340 mW x Exposure dose <= Exposure time ab

8. Let us now see how with this kind of light source a CP20 print film can be exposed. First of all, we have to calculate the spectral emission for a 1200 Watt incandescent lamp. This higher power lamp (1200 W instead of 100W) with the same colour temperature (3350 K), only differs in spectral output magnitude. ab

9. How is CP20 composed? Sensitized for Producing Green Magenta Red Cyan Blue Yellow Polyester On top of this, there is: - a protective layer on both sides of the film - a layer in between the dye producing layers - an antihalation layer between the blue sensitive layer and the base, protecting the polyester in the case of laser subtitling. ab

10. Let us calculate the actinic energy Spectral sensitivity of the different layers Linear spectral sensitivity linear This is without the use of any optical filter ! X Resulting actinic energy Spectral emission of the lamp = ab

11. The use of optical filters For normal analogue tracks only a yellow filter is used. For high magenta a yellow filter and some cyan is used ab

12. The effect of an optical filter Spectral emission of the lamp Filter characteristic x = Resulting actinic energy Resulting spectral output ab

13. So what is the difference ? Without yellow filter With yellow filter ab

14. And finally, colours are here... Let us start with the dye densities If we convert them into a linear scale... ab

15. Additional silver density. To produce dye density, sensitized silver has to be exposed. In conventional soundtracks silver is redeveloped. Also high magenta tracks are redeveloped, the only difference is the density levels. ab

16. The final soundtrack. The total soundtrack density is a mixture of different components. ab

17. What about the soundtracks on the film ? On the sound negative On the colour print ab

18. A little bit deeper in photography An analogue soundtrack in practice. Dmax Dmin Image spread ab

19. Practical measurements on CP20 print film D= 1.5 D= 3 D= 3.6 ab

20. Practical measurements on a ST8D sound negative. D= 3.6 What does this mean ? Because image spread is related to density, to find the optimum neg/pos combination a cross modulation test is always necessary. ab

21. The results of a x-mod test. ab

22. How does the analogue sound system reproduce the recorded information? -The sound is recorded in a double, variable area track. -The film is transported through a reader system. -The reader “looks” through a narrow slit. -The reader detects area variations. ab

23. A little bit of mathematics... Dmax. Dmin. Sin wt 10Dmin 1- Sin wt 10Dmax k .{ } S(t) = + ab

24. The previous formula visualized. Sin wt 10Dmin 1 10Dmax - Sin wt 10Dmax ab

25. Signal level as a function of contrast. With the contrast of the analogue sound track defined as Dcon = Dmax - Dmin and the previous formula solved as a function of this contrast, leads us to the following graph, Conclusion. By means of the nominal density aim value a signal level reaching 90% of the theoretical maximum level can be obtained. ab

26. Exposure of a colour print film Dye track Conventional silver track Conclusion By means of the colour balance of both dyes, dye tracks can be adapted selectively to the spectral characteristics of the reader system. However since there is a mixture of white and red readers in the field, track performance needs to be adapted to both of them, leading to high magenta. ab

27. Let’s go back to basics now. Sin wt 10Dmin 1- Sin wt 10Dmax k .{ } S(t) = + 1 10Dmin 1 10Dmax S(t) = k f(t) { - } S(t) = k.f(t).d(l) 1 10Dmin(l) 1 10Dmax(l) d(l) = - This equation defines the signal level response completely. ab

28. A practical example 1 10Dmin(l) 1 10Dmax(l) d(l)= - ab

29. The reader with practical elements Incandescent lamp fL(l) Red LED d(l) Film fD(l) Detector S(l) Resulting signal ab

30. Introducing the film into this setup. To introduce the film in this system without disturbing the response of it the signal response d(l) needs to be flat in the used part of the spectrum. ab

31. Corresponding dye characteristics ab

32. Also other dye density ratio’s are possible ! The correct choice is defined by a X-mod test. ab

33. Exposing the colour print film for a high magenta track. ab

34. Recommended aim densities and filters. Sound system Neg.density Print density Filter pack Silver tracks 2.5 - 3.0 1.25 - 1.5 #12 Yellow #2B UV blocker High Magenta 2.5 - 3.3 R= 1.5 - 2.3 #12 Yellow G <= 3.8 - 4 #90 - 120 Cyan IR= 1 - 1.2 or AGFA G00004 Cyan dye track 2.3 - 3.2 R= 1.5 - 2.5 #29 Red G&B= 0.3 - 0.5 or AGFA L622 SRD 1.2 - 1.75 1.2 - 1.4 #170 Yellow # 20 Magenta # 2B UV blocker SDDS 2.0 - 2.5 R= 1.2 - 1.4 #29 Red G <= 1 or B <= 0.35 AGFA L622 ab

35. Why high magenta soundtracks ? Red readers are being installed more and more: 62 % in USA (NATO report) 25 % in Europe 4 % in Eastern Europe. A soundtrack, not exposed for high magenta has a signal loss of 12dB on a red reader system. So the high magenta technology is an intermediate step between conventional silver tracks and cyan dye tracks. ab

36. What about the advantages of pure dye tracks ? For the labs: No more redevelopment. A safer processing. Therefore savings of cost. For the theatre owner: A much higher reliability because of the red reader. For the theatre visitor: A higher frequency response. ab

37. What about the production of dye tracks ? Because of the red readers, we only need CYAN dye density. To print pure cyan dye tracks we only need a RED filter. Dye tracks will end up with: the same quality compared to conventional silver tracks, being produced at lower costs and lower risks. ab

38. What is the situation for this moment ? Distributors now ordering high magenta prints include: Warner Bros. (100% in USA) Universal Studios (selected titles) Fox (100% in USA) Fox Searchlight Miramax New Line The introduction of dye tracks will be pre-announced at Showest 2001 ab

39. And finally.. Let us always remember, that: Experience is what you get if you don’t get what you want… Many thanks for being here today. ab