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

abab 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

abab 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.

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

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

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

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

abab 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.

abab How is CP20 composed? Polyester Yellow Cyan Magenta Blue Red Green Sensitized forProducing 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.

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

abab 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

abab Spectral emission of the lampFilter characteristic Resulting spectral outputResulting actinic energy The effect of an optical filter x =

abab So what is the difference ? With yellow filter Without yellow filter

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

abab 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.

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

abab What about the soundtracks on the film ? On the sound negative On the colour print

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

abab Practical measurements on CP20 print film D= 3 D= 1.5 D= 3.6

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

abab The results of a x-mod test.

abab 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.

abab A little bit of mathematics... S(t) =  Sin  t 10 Dmin + 1- Sin  t 10 Dmax

abab The previous formula visualized. - Sin  t 10 Dmax Sin  t 10 Dmin 1 10 Dmax

abab Signal level as a function of contrast. With the contrast of the analogue sound track defined as D con = D max - D min 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.

abab Exposure of a colour print film Conventional silver trackDye 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.

abab Let’s go back to basics now. S(t) =  Sin  t 10 Dmin + 1- Sin  t 10 Dmax S(t) =  f(t) { - } 1 10 Dmin 1 10 Dmax S(t) = .f(t).  ( )  ( ) = 1 10 Dmin( ) 1 10 Dmax( ) - This equation defines the signal level response completely.

abab A practical example 1 10 Dmin( ) 1 10 Dmax( ) -  ( ) =

abab The reader with practical elements Incandescent lamp Film Detector Resulting signal  L    D  S( ) Red LED

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

abab Corresponding dye characteristics

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

abab Exposing the colour print film for a high magenta track.

abab Recommended aim densities and filters. Sound systemNeg.densityPrint densityFilter pack Silver tracks #12 Yellow #2B UV blocker High Magenta R= #12 Yellow G <= # Cyan IR= or AGFA G00004 Cyan dye track R= #29 Red G&B= or AGFA L622 SRD #170 Yellow # 20 Magenta # 2B UV blocker SDDS R= #29 Red G <= 1or B <= 0.35AGFA L622

abab 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.

abab 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.

abab 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.

abab 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

abab 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.