Archive-Name: movies/tech/part3
Posting-Frequency: monthly
Last-Modified: 6/96
Version: 0.02

          /-----------------------------------------------------------\
          |                   rec.arts.movies.tech                    |
          |             Frequently Asked Questions (FAQ)              |
          |                      (with answers)                       |
          |                                                           |
          |                       Part 3 of 4                         |
          |                                                           |
          |                       Version 0.02                        |
          |            (supersedes all previous versions)             |
          |                        June, 1996                         |
          |                                                           |
          |                                                           |
          |              Compiled, Edited, Maintained by              |
          |                     Scott E. Norwood                      |
          |                     snorwood@nyx.net                      |
          \-----------------------------------------------------------/
                      Copyright (C) 1996 by Scott E. Norwood

          This document may be freely distributed by electronic, paper,
          and  other  means, provided  that  it is  distributed in  its
          complete,   unmodified   form   for   non-commercial   and/or
          educational   purposes.    Commercial  use  of  the  material
          contained   herein  is  not  permitted, unless prior  written
          permission  is  obtained from the  copyright  holder.  Others
          who  have  contributed to this  document retain the rights to
          their own contributions (which are noted).

                                   DISCLAIMER:

          The  compiler  of  this  document has attempted to make every
          reasonable effort  to ensure that any  information  contained
          herein  is accurate  and complete.  However, the compiler  is
          unable to assume responsibility, legal or  otherwise, for any
          inaccuracies, errors,  or omissions  relating  to the inform-
          ation contained below.  All of  the information  contained in
          this document is believed by its compiler to  be held  in the
          public  domain.  The  compiler is  not affiliated with any of
          the  companies whose products are mentioned here, nor does he
          necessarily endorse these products. All statements about such
          products  are  for informational  use only.  U.S.  trademarks
          are indicated  by (tm)  where applicable,  and  are used here
          without the permission of their owners.

                    -----------------------------------------

TABLE OF CONTENTS:

5.0  Motion Picture Presentation (theatrical projection)

  5.1   What type of projection and sound equipment is commonly used for
        commercial theatrical presentation?

    5.1.1   Projector/Lamphouse
    5.1.2   Sound System

  5.2   What are some specific examples of a common projection setup?
  5.3   What are the differences between xenon and carbon-arc lamphouses?
  5.4   How are 'seamless' manual reel changeovers accomplished?

    5.4.1   Shipping Configurations for 35mm Prints
    5.4.2   Changeover Procedures

  5.5   How does a platter system work?

    5.5.1   Platter Configurations
    5.5.2   Platter Operation

  5.6   How are multiple projectors interlocked to run the same piece of film
        in multiple auditoria?
  5.7   What are the industry standards for image brightness and screen
        reflectivity?
  5.8   What are the industry standards for sound levels in a mono setup?
  5.9   What are the industry standards for sound levels in a Dolby Stereo
        (tm) setup?
  5.10  How does a dual-format (35/70) projector work, and how is the
        changeover made between formats?
  5.11  What are the differences between nitrate-, acetate-, and polyester-
        based print stocks?

    5.11.1   Nitrate Base/Triacetate (Safety) Base
    5.11.2   Polyester Base

  5.12  What is the best way to avoid the static and shedding problems
        common in polyester prints?
  5.13  What precautions are necessary when projecting nitrate prints?
  5.14  What are the proper procedures for print inspection prior to
        showing a film?
  5.15  What other problems are common in film projection, and how does
        one fix them?

6.0  Film Laboratories

  6.1   What are the differences between reversal and negative film,
        and which is the most common?

    6.1.1   Differences Between Reversal and Negative Films
    6.1.2   Uses for Reversal and Negative Films

  6.2   What is a 'one light work print'?  A 'timed work print'?
  6.3   What does a negative cutter do?

    6.3.1   General Information on Negative Conforming
    6.3.2   A & B (& C) Roll Conforming and Printing

  6.4   What is timing/color timing, and how does it affect the look
        of filmed images?
  6.5   What is an 'answer print'?
  6.6   What is an 'interpositive'?  An 'internegative'?
  6.7   What is a 'check print'?
  6.8   What is a 'release print'?
  6.9   What is the difference between release prints made for projection
        with tungsten lamps and release prints made for projection
        with xenon lamps?
  6.10  What is a 'low-contrast print'?
  6.11  What is 'green film'?  Why isn't it green?
  6.12  What are currently the standard reel/can sizes for the various film
        formats?
  6.13  How can I process reversal films at home?

                    -----------------------------------------

5.0  Motion Picture Presentation (theatrical projection)
--------------------------------------------------------

  5.1   What type of projection and sound equipment is commonly used for
        commercial theatrical presentation?

    5.1.1   Projector/Lamphouse

     Obviously, the projector is the most critical part of any theater's
projection setup, for, without the projector, there would be no movies.  Many
newly installed theaters use old, rebuilt Simplex or Century 35mm projectors.
While these projectors are readily available brand-new, some feel that their
quality of construction is less than desirable.  Thus, the demand for rebuilt
projector heads.  The most common Simplex models are the Simplex XL (a.k.a.
Pro 35, a currently manufactured model), the older Simplex E-7, and the
really old Super Simplex.  The most common Century model is the ??.

     Larger theaters built from the 1960's through the 1980's may instead
be using combination 35/70mm projectors, like the Norelco AA-II (known
in Europe as the Philips DP-70), and Century JJ, although, with the decreased
availability of 70mm features of late, most of these machines are either
used exclusively for 35mm shows or are sitting idle.

     Most modern theaters use xenon bulb lamphouses of between 2 and 4
kilowatts.  This provides a picture of adequate brightness on the medium-
sized screen common in multi-screen cinemas.  A larger lamphouse of up to 10
kilowatts is needed for a very large screen, such as that of a drive-in
theater.  Older theaters often still use carbon-arc lamps, which require more
attention on the part of the projectionist than xenon, but some feel that
they offer a light of better color temperature (i.e.  not as cold-looking)
than xenon.

     As for the film handling system itself, automated cinemas usually use
film 'platters,' in which the entire print is loaded onto a large plate-like
device (with the film from the individual 2000' shipping reels spliced
together), permitting one projectionist to operate the projection equipment
for many auditoria.  Smaller theaters and older theaters often use two
projectors with small reels, each holding either 2000' each (just like the
shipping reels) or 6000' each (with the contents of three shipping reels
spliced together).  Between the reels, the projectionist operates a change-
over mechanism, simultaneously switching over machines and soundtracks.  He
then rewinds the next reel, reloads it on the idle projector and prepares
for the next changeover.

    5.1.2   Sound System

     The sound system in a typical theater installation is capable of
handling from 200-400 watts of power for the front channels.  In a mono
system, several loudspeakers are located behind the screen, reproducing
a single channel of sound.  A Dolby Stereo (tm) system involves at least
three loudspeakers behind the screen to reproduce the front channels,
as well as several loudspeakers along the side and rear walls of the
auditorium to reproduce the 'surround' channel of sound.  The soundtrack
itself is read from the film by a solar cell arrangement within a soundhead,
commonly a Simplex SH-1000.

Typical Multi-Track Dolby Stereo/SR-D/DTS setup:
  (This is the same setup used for Dolby (tm) Stereo, DTS (tm), and SR-D
  setups, although the digital systems have separate L and R surround
  channels, as well as a channel for a subwoofer [which is located behind
  the screen].  Complete SDDS systems also have Left Center [LC] and Right
  Center [RC] loudspeakers, not indicated here)

      Left Stereo     (L) -- behind left side of screen
      Right Stereo    (R) -- behind right side of screen
      Center/Dialogue (C) -- behind center of screen
      Surround        (S) -- in rear of auditorium (separate L/R in digital)
      Subwoofer     (sub) -- behind screen (digital only)

/----------------------------------------------------------\
|        *  L   *         *  C   *         *  R   *        |
|        * spkr *  (sub)  * spkr *         * spkr *        |
|      ------------------- screen -------------------      |
|                                                          |
|                  (front of auditorium)                   |
|                                                          |
|        UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU        |
|        UUUUUUU  UUUUUUU audience UUUUUUU  UUUUUUU        |
|        UUUUUUU  UUUUU seating area UUUUU  UUUUUUU        |
|        UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU        |
|        UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU        |
\                                                          \
/                                                          /
\                                                          \
|* S  *  UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU  * S  *|
|*spkr*  UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU  *spkr*|
|        UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU        |
|        UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU        |
|* S  *  UUUUUUU  UUUUUUUUUUUUUUUUUUUUUUUU  UUUUUUU  * S  *|
|*spkr*                                              *spkr*|
|        * S  *                              * S  *        |
|        *spkr*     (rear of auditorium)     *spkr*        |
\----------------------------------------------------------/

     Digital sound systems use similar loudspeaker arrangements as Dolby
Stereo (tm) setups, possibly with additional loudspeakers to support SDDS (tm)
eight-channel mixes.  The sound is read by specialized readers placed between
the reels/platters and the projector head; this contrasts with the placement
of the analog soundhead, which is located between the projector head and
the take-up reel/platter.

  5.2   What are some specific examples of a common projection setup?

  [under construction]

  5.3   What are the differences between xenon, and carbon-arc lamphouses?

  [under construction]

  5.4   How are 'seamless' manual reel changeovers accomplished?

    5.4.1   Shipping Configurations for 35mm Prints

     Nearly all 35mm prints are shipped on metal reels which hold 2000' of
film.  Often, the films are shipped 'tails out,' meaning that the beginning
of the film is at the middle core of the first reel, and the end is at the
outer edge of the last reel.  These reels are shipped in so-called 'S-wind,'
meaning that the emulsion (dull side) winds facing 'out' when the 'tail' is
'out,' and that, when rewound, the 'head' should face 'out,' and the
emulsion will wind 'in.'  This confusing standard is considered to help
prevent print damage.

     By August of 1996, new prints are likely to be shipped on the so-called
Extended Length Reel (ELR), which is capable of holding 6800' of standard
triacetate film or 8000' of the thinner polyester stock.  This is expected
to reduce the amount of time needed to build up a print on platters, and
possibly reduce the damage done in the buildup/breakdown process.  This
standard is supported primarily by the exhibitors (who will save in labor
costs) and film laboratories (although some will need to buy new equipment
to handle the larger reel sizes).  Presumably, at least for a certain
amount of time, 2000' reel sizes will also be distributed for these films,
in order to accommodate theaters which do not have platters or 6000' reel
arms, and must instead run the films with 2000' reels.  Eventually, these
houses may have to convert to 6000' changeover/platters or cut up
the ELR prints themselves.

     It should be noted, also, that nitrate prints have usually been (and
still are) shipped on 1000' reels, due to fire-hazard concerns.  This
configuration presents less of a danger, should one reel catch fire, as
there is less film to burn.  These nitrate films also are usually stored
on metal shelving, in asbestos-insulated fire-proof rooms.  Modern
triacetate or polyester films, of course, do not require these precautions.

     When the film arrives at a changeover house, the head projectionist
rewinds the film onto cast-iron house reels, inspecting the print for damage
and splices, as well as (hopefully) ensuring that the changeover cue marks
are properly positioned.

    5.4.2   Changeover Procedures

     Just before the show starts, the first (house) reel is loaded in one
projector and the second reel is loaded into the other.  The first projector
is started; a few minutes before the first reel ends, a bell on the reel
arm (activated either by the increased rotation speed of the reel, or by
the decreased weight of the reel) may ring to alert the projectionist of the
upcoming changeover (although newer reel arms are less likely to have this
feature).  The projectionist then stands before the second machine, looking
out at the screen, waiting for the first cue mark (a small dot in the upper-
right-hand corner of the picture for four consecutive frames [made by
punching holes into the internegative; they appear round on 'flat' prints
and, due to the 'unsqueeze,' elliptical on 'scope prints]).  Upon seeing
this, he hits a button on the changeover controller, striking the lamp (if
this is the first changeover; otherwise, the lamp (if xenon) will have
already been struck, and will not be turned off until the end of the show;
this avoids excessive thermal stress, which causes bulbs to burn out, and
avoids the embarrassment of having the bulb burn out when first struck,
right before a changeover), and starting the motor on the second machine.

     The second reel has, hopefully been loaded up properly in the
second machine, with the framelines lined up with the top and bottom
edges of the gate (if this is not done, the film will probably appear
out of frame, and the projectionist will have to manually adjust the
projector's 'framing' knob in order to position the picture correctly on the
screen.  The projectionist should have timed the second machine's  'run-up'
(the time that it takes for the motor to get up to speed), and has
positioned the film leader accordingly.  Usually, about three seconds of 
time are lost in the run-up.  Two types of leader are currently found on
release prints.  New SMPTE Universal Leader is marked off in seconds of
time (considered to be more useful for television stations), and counts
down from '8' to '2'.  This is used on nearly all new prints.  Older Academy
Leader is marked off in feet of film, counting from '11' to '3,' and is
common on older prints.  The projectionist simply remembers which frame
of each type of leader needs to be loaded into the projector in order to
give the correct 'run-up' time between cue marks.  If the leader is not
complete and the projectionist is not able or willing to replace it, he
must wait after the first cue mark (before starting the motor on the second
machine) until roughly where the next reel was loaded.

     Once the second projector is going, the projectionist waits for a
second dot, located 22 frames from the end of the first reel.  Within a
half-second or so after seeing this, he hits another button, which switches
over the soundtrack, and simultaneously opens (on the machine holding the
second reel) and closes (on the machine holding the first reel) a metal
'changeover' blade (a.k.a. the 'dowser') which allows or disallows the
passage of light through the film and, of course, onto the screen.  The
first reel is either stored in the film's metal shipping case, or rewound
back onto a house reel on a rewind bench.  The process is repeated for
every reel change.

  5.5   How does a platter system work?

    5.5.1   Platter Configurations

     Platter systems are used commonly in 'automated' booths, allowing one
projectionist to run several shows (such as in a multi-screen theater)
simultaneously by eliminating the need for manual changeovers and the
rewinding of reels.  The platter itself is a large, flat, circular, metal
table, mounted on a column of like plates, on which the film is wound,
tails out, with the shipping reels all spliced together.  Platters are
usually installed in stacks of three, allowing two films to be ready to
run at any one time, along with a takeup platter for either.  This setup
also allows one print to be made up/broken down while another is running.

    5.5.2   Platter Operation

     After the print is spliced together, the projectionist removes the
metal core, (a.k.a.  the 'donut') around which the film is wound 'tails
out', from the center of the platter, loads the film across a series of
rollers and through the projector, and attaches the donut to an empty
platter.  The film feeds out the center of the first platter, and is taken
up on the second one.  In this way, a show may be started, and,
as long as no problems occur, run through its end without continual
supervision.  Because the film is taken up with the head at the center
of the platter, there is no rewinding necessary.  To run the same film
again, the film is fed from its current platter onto another empty one.
This can potentially save time by eliminating the rewind stage, allowing
the same show to be run almost continuously.

     So-called 'endless loop platters' also exist, and work similarly,
although they omit the donut, and instead require that the head and tail
be spliced together, allowing the same film to be run multiple times with
no interruptions.  Unfortunately, though, these systems discourage the
cleaning of the projector gate, and, as dust and dirt accumulate there
(an inevitable result of showing films), can lead to print scratches and
other damage.

     After building up a print on a platter, it is good practice for the
projectionist to run it once in order to preview the print for any
problems which may have been introduced in print buildup (like bad splices)
and other defects, which may have been introduced elsewhere (like deep
scratches, or lousy lab work).  Splices used to build up prints on platters
are usually made with 'zebra' tape, which has yellow markings which help
the projectionist to locate the splices when breaking down the print
onto the shipping reels.

  5.6   How are multiple projectors interlocked to run the same piece of film
        in multiple auditoria?

  (information courtesy David Richards <daverich@netcom.com>)

     This is occasionally done in multiple-screen theaters; the projectors
which are going to be interlocked need to be adjacent to each other (or
at least reasonably close), and must be fitted with synchronous motors,
whose speed is controlled by the 60hz (in the U.S.; 50hz in many other
countries) AC line frequency.  The film is loaded from a platter through
the first projector (as usual), and then passes over several rollers,
mounted on a wall or ceiling, across the booth to the second projector,
into which it is then also loaded normally.  Somewhere between the two
machines, there is usually a bit of slack in the film, where a weighted
roller is placed in order to keep the film running smoothly if there
happens to be a small speed variation during the show.

     Both projectors must be started at exactly the same time in order to
maintain the proper amount of slack between them.  This is done either by
two projectionists, or by an automation system capable of handling this
function.

     It should be noted that the term 'interlocked' is also commonly used
in the context of a sound mix facility, where several magnetic dubbers,
and, usually, a projector, must be mechanically or electronically
interlocked together in order to ensure that the multiple soundtracks
being mixed are in perfect sync with each other and with the workprint
being projected.

  5.7   What are the industry standards for image brightness and screen
        reflectivity?

  [under construction]

     According to the Society of Motion Picture and Television Engineers
(SMPTE), the generally accepted standard-setting organization for the
industry, films are to be projected at a brightness level of 16
footlamberts (+/- 2 footlamberts).  There is no standard for screen gain,
and it varies substantially from theater to theater (from 1x to 3x is
common).  Screen gain deteriorates over time, and thus requires that
screens be replaced periodically.

  5.8   What are the industry standards for sound levels in a mono setup?

  [under construction]

  5.9   What are the industry standards for sound levels in a Dolby Stereo
        (tm) setup?

  [under construction]

  5.10  How does a dual-format (35/70) projector work, and how is the
        changeover made between formats?

  [under construction]

  5.11  What are the differences between nitrate-, acetate-, and polyester-
        based print stocks?

    5.11.1   Nitrate Base/Triacetate (Safety) Base

     Early motion pictures were all shot and printed on nitrate-base film.
This became extremely flammable as it aged, and thus unsuitable for
use in non-fireproofed environments (such as homes and schools).  Thus,
'safety film' was invented, which had a biacetate (later, triacetate), or
similar, base.  This was initially used for 16mm films (which were never
manufactured on nitrate [except in Russia, for a short time], due to
concerns about home use), and eventually came into use for 35mm presentation
as well.  The last nitrate film manufactured by Eastman Kodak (tm) was
delivered in 1953.  With the introduction of safety film, the projection
and storage of nitrate films was outlawed or severely restricted by many
communities.  As film librarians have found, nitrate, being an unstable
base by nature, tends to decompose easily, and many old nitrate films which
have not been re-printed onto safety film have deteriorated beyond the
point of recovery.  When nitrate prints are shown today, it is common to
remove a small piece of head or tail, and light it.  The speed at which
the film burns can be used to determine whether or not the film can
be run in relative safety.

    5.11.2   Polyester Base

     Polyester stock ('ESTAR' is a trademark for polyester stock manu-
factured by the Eastman Kodak (tm) company) is a fairly new development for
print film.  Like triacetate stock, it is nonflammable.  The primary
differences between it and the older nitrate/triacetate stocks are strength
and thickness.  Unlike other films, polyester stock DOES NOT BREAK.  If
stressed, it simply stretches.  This can be either good or bad, depending
upon the degree to which it is stressed; for example, a jammed platter feed
mechanism can cause the still-running projector to pull an essentially
immovable piece of film through it, causing great damage to the projector
itself, and, of course, damaging several feet of the film.  If this
circumstance occurred with triacetate film stock, the film would have
simply broken, and no damage would have occurred.

     The severity of this and other problems varies substantially among
films manufactured by different companies.  Further, the resistance to
breakage is the primary reason why polyester is not used on camera films, as
the risk of damage is much greater when the film is run through expensive
camera equipment.  (Polyester camera film is manufactured and used for
high-speed cameras used to capture slow-motion images for scientific
and engineering work, as the mechanisms of these cameras run so quickly
that they would be severely damaged if the film were to break while the
camera was running).

     Polyester stock is also thinner and lighter than acetate stock (one can
identify it as polyester by holding a reel up to a light source; if one can
see light through it, then it is polyester).  This can reduce the number
of shipping reels, and the shipping cost, but may require adjustment of
gate pressure in the projector in order for the film to run properly.  Also,
the stock is more sensitive to low humidity than triacetate, as it tends
to pick up static electrical charge, sometimes preventing it from running
smoothly on a platter system.  The most often recommended solution to this
ailment is to ensure that the platters are properly grounded, and that
a humidifier is present in the projection booth.  This will also help
to avert unnecessary dust accumulation on the print.

     The texture of polyester stock is substantially different from that
of triacetate stock, and cement splices are not particularly effective
on polyester films.  Thus, projectionists usually use the more-visible
tape splices to join film together.

     The static and strength problems were particularly acute with many
prints of _American_President_, one of the first major features to have
35mm prints distributed on polyester stock.  Commonly, when run on platters,
the film layers would 'stick' together, jamming the feed mechanism, and,
usually, causing the whole projector to stop (by means of 'failsafe'
assemblies which stop the motor when there is excessive tension on the
guide rollers).

     It should also be noted that the IMAX (tm) format requires that
polyester-based film be used, due to the relatively high linear speed
at which the film moves through the projector (about three times that
of 35mm), and the potential damage to the projector should there be
a film break in the middle of a show.  However, IMAX (tm) equipment
was designed for polyester film, and has several safeguards not present
in most 35mm projection equipment in order to avert potential disasters
in the projection booth.

  5.12  What is the best way to avoid the static and shedding problems
        common in polyester prints?

  [under construction]

  5.13  What precautions are necessary when projecting nitrate prints?

  [under construction]

  5.14  What are the proper procedures for print inspection prior to
        showing a film?

  [under construction]

  5.15  What other problems are common in film projection, and how does
        one fix them?

  [under construction]

                    -----------------------------------------

6.0  Film Laboratories
----------------------

  6.1   What are the differences between reversal and negative film,
        and which is the most common?

    6.1.1   Differences Between Reversal and Negative Films

     The difference is quite simple:  with negative film, the images on the
camera film are reversed such that light areas become dark, and dark areas
become light (just like a still photographer's negatives).  The camera
negative cannot be properly projected, as a positive print (duplicate film) 
(with the light areas light and dark areas dark) must first be made, and
then this print is used for projection.  With reversal film, the camera
original can be properly projected.

    6.1.2   Uses for Reversal and Negative Films

     Home movies, old television news footage, and some military and NASA
films are shot on reversal film for convenience and the cost savings of
not having to make a separate print for projection.  Nearly everything
else is shot on negative film, as prints made from it are cheaper than
those from reversal; additionally, it has far greater exposure latitude
(tolerance for over/underexposure) than reversal film.  Finally, professional
film-makers do not want to damage the camera original in the editing process,
and so the convenience and cost advantages of reversal film are negated.

  6.2   What is a 'one light work print'?  A 'timed work print'?

     Film 'dailies' (quickly made prints of camera negative) are often
known as 'work prints,' as, after they are viewed by directors and
cinematographers, they are the actual prints with which film editors
(assuming they actually are editing on _film_) 'work' as they cut
and splice the film together to appropriately reflect a film's story.
Work prints come in two varieties:  one light and timed.  A 'one light'
print is simply a print made without extensive scene-to-scene exposure
and color (if the film is in color) correction (known as 'timing').  A
timed print, on the other hand, is more expensive, and involves several
'lights' (exposure/color corrections) in order to make the images look
prettier.  These timed prints can help the director, editor, and cine-
matographer gain a better idea of how the final prints will look.

  6.3   What does a negative cutter do?

    6.3.1   General Information on Negative Conforming

     After a workprint (or videotape transfer of camera negatives) is
edited, the original camera negatives must be matched ('conformed') back
to the workprint, so that prints can then be made from the negatives.  This
is a job done by a negative cutter, who uses the 'edge numbers' or 'keycodes'
printed (by the manufacturer of the raw stock) on the edge of the camera
negative and then printed through on the workprint.  These numbers
are printed every 20 frames in 16mm and every 16 frames in 35mm, and
are the reference points for the negative cutter.  'Keycodes' are simply
barcode versions of human-readable edge numbers, and permit the cutting
of negatives to match edited videotape transfers from negatives (provided
that the transfers have 'window burns' in the corner of the picture,
showing the proper keycode numbers for the film being transferred).

    6.3.2   A & B (& C) Roll Conforming and Printing

     Films in 16mm and sometimes 35mm are cut into so-called 'A & B rolls,'
in a 'checkerboard' fashion in order to ensure that splices will not appear
on the screen when the prints are projected.  This technique is best
described with the following diagram:

          ------------------------------------------------------------------
'A roll'  | <----scene 1----> | <----black leader----> | <----scene 3----> |
          ------------------------------------------------------------------

          ------------------------------------------------------------------
'B roll'  | <--black leader-> | <-------scene 2------> | <--black leader-> |
          ------------------------------------------------------------------

     The print film is then run through the printer (at the lab.) thrice,
first exposing it to the 'A roll,' then rewinding, then exposing it to
the 'B roll,' then rewinding, then exposing it to the soundtrack.  The
completed print (if printed properly) contains all scenes in order
without visible splices in between, as well as an in-sync soundtrack.  If
white titles are needed, then the print film is run through again, this
time being exposed to a 'C roll,' containing main or subtitles.  Fades
and dissolves (cross-fades between scenes) are made at this time too,
using either a punched paper tape or notches in the edges of
the negatives as cues.

     This A & B roll method is not always necessary for 35mm, as enough
of the area around the frameline is masked off in projection to permit
splicing the film negatives into a single strand which can be printed
in one pass through the printer, instead of two.  The A & B rolls are
necessary, though, for dissolves between scenes, and for superimposed
images.

  6.4   What is timing/color timing, and how does it affect the look
        of filmed images?

     Color timing has a great effect on filmed images, as it controls
the 'look' of the film, with respect to exposure and color balance, as
well as scene-to-scene continuity.  The color timer uses a machine known
as a 'Hazeltine' (tm) which reverses images on the original negatives and
displays them on a television-like screen, and then turns dials to assign
the image 'printer's points' for each of the three primary colors (red,
green, blue).  These 'points' range from 0 to 50, with about 25 being
'normal,' with higher numbers making the image darker, and lower numbers
making the image lighter.  In practice, the 'normal' values vary depending
upon the camera stocks used and the cinematographer's personal preferences
for exposure.

     When working with black-and-white films, only one set of points
is used, as there is no color balance to worry about.  In this case,
the 'timer' simply manipulates the exposure of the image.  Incidentally,
the term 'timer' comes from the days before automated printers when the
'timer' actually had to determine how long certain portions of the print
should be allowed to sit in the developer.  Of course, this is no longer
necessary, and all print films are processed in the same manner.

     Each scene is timed, and the printer's points for each scene are
encoded onto a punched paper tape or as notches in the edges of the
negatives (just like fades/dissolves).  The printer then reads these
cues and electronically adjusts its lights and filtration to match
the cues.

  6.5   What is an 'answer print'?

     The first print made from original camera negatives is called the
'answer print,' and it is intended to give the cinematographer and director
an 'answer' to their questions about how certain scenes are to be timed.
This print is commonly screened at the lab's screening room, with the color
timer present to discuss the timing of certain scenes.  If adjustments
need to be made, additional answer prints are made until everyone is
satisfied with the 'look' of the print.

  6.6   What is an 'interpositive'?  An 'internegative'?

     Large print runs (like the 1500-2500-print orders for today's feature
films) are potentially damaging to the valuable camera negatives, and so
most theatrical prints are made from 'intermediate' films.  Some image
quality is lost in the process, however.  The process generally goes
as follows:  The A, B, and C (if necessary) rolls, and the optical soundtrack
(and digital soundtrack[s], if used) are all printed onto an interpositive,
which has lower contrast than ordinary release-print stock (contrast builds
up in the internegative and release print stages).  This interpositive
is then printed onto one or more internegatives, which is/are then used
to print theatrical prints.  If foreign distribution is expected, the C
roll (containing titles) is sometimes printed separately on its own
interpositive, and then both interpositives are printed onto the
internegative(s).  This allows for different versions of a film's
titles, which can be made in different languages for foreign prints;
subtitles for foreign prints can also be added by splicing them into the
'title' interpositive.

     Note that prints made from internegatives must be run through the
printer only once, as the internegative contains all of the elements
(A/B/C rolls, optical track) necessary for the print, whereas original-
negative prints must be run through the printer at least three times.  Thus,
prints made from internegatives are about 1/3 less expensive than original-
negative prints.

  6.7   What is a 'check print'?

     A 'check print' is the first print made from an internegative, to
ensure that all of the elements are lined up properly, and that the sound-
track is in sync with the picture.  If a check print is acceptable, then
all release prints will look similar, with everything in sync, because
they will be printed from the same internegative(s).

  6.8   What is a 'release print'?

     The 'release print' is made from the internegative (as mentioned above),
or, for very small print runs or special engagements, from camera negatives.
These are the prints which are shipped to theaters and other exhibitors
for the exhibition of motion pictures.  Release prints differ from answer
prints, check prints, and intermediates, in that they are mounted on metal
reels for projection (the others come on small plastic lab 'cores' and must
be mounted in 'split reels' for projection), and, like check prints, have
reel-change cues at their tails.  They are the least-expensive type of
final print.

  6.9   What is the difference between release prints made for projection
        with tungsten lamps and release prints made for projection
        with xenon lamps?

     The color balance.  Tungsten lamps have a 3300 degree Kelvin 'color
temperature,' whereas xenon lamps have a 5500 degree Kelvin color
temperature.  Basically, xenon lamps give a 'bluer' light than tungsten
lamps (carbon-arcs fall somewhere in between).  To compensate for this,
a small filter is changed in the printer to make prints for both
types of lamps.  This change is independent of the print timing, and so
can be made well after the timer is completed with his job.  In practice,
however, all theatrical prints are balanced for xenon, as no commercial
theater commonly uses tungsten lamps.

  6.10  What is a 'low-contrast print'?

     It is similar to an interpositive, and is used for television/video
tape transfers.  These transfers often increase image contrast, and so
are improved when they are mastered from a low-contrast print.  These
prints can be projected as well, but lack the color saturation and
(obviously) contrast of a standard release print.

  6.11  What is 'green film'?  Why isn't it green?

     'Green film' is simply a term used for film which is fresh from the
lab, and is still somewhat moist from the processing chemicals and
lubricants used at the lab.  It requires slightly more attention upon
projection, as the moisture and lubrication can prevent this film from
running steadily through the projector.  This is why some perfectly good
prints seem to have lousy registration when they have just been returned
from the lab.

  6.12  What are currently the standard reel/can sizes for the various film
        formats?

     In 8mm/16mm/35mm:  100', 200' (not 35), 400', 800' (not 35), 1000',
                        1200' (not 35), 1600' (not 8, 35), 2000' (not 8)

  6.13  How can I process reversal films at home?

(courtesy Ed Inman <edinman@teclink.net>)

> From: edinman <edinman@teclink.net>
> Newsgroups: rec.arts.movies.tech
> Subject: (no subject)
> Date: 7 Jun 1996 01:50:18 GMT
>
> Here is my advice on how to reverse process your Super 8 or 16mm black
> and white movies at home. Why would you want to do this? There are
> several reasons. For example, the film may be of a personal or sensitive
> nature that you would feel uncomfortable sending out to a lab. But the
> best reason to home process your film is that you get to see it right
> away, instead of sending it off and waiting.
>
> There is not much that has been written on this subject in years, so the
> following suggestions are based only on my personal experimentation. If
> anyone who has experience with this sort of thing would care to make
> suggestions on how I could improve or refine this process, or would like
> to ask any questions, feel free to e-mail me.
>
> HOME B&W MOVIE/SLIDE PROCESSING:
> The only home movie processing tank still sold that I am aware of is the
> G-3 Daylight Processor sold by Doran Enterprises in Milwaukee,
> Wisconsin, USA. Their phone number, if you wish to order one is
> 414-645-0109.
>
> The tank is not ideal--the good news is that it only takes one liter (or
> one quart) to process up to 200 ft. of Super 8 or 16mm film (or about
> 1.5 liters for 35mm film). The bad news is that it is kind of tedious to
> use.
>
> Since it is a "rewind" tank, the operator must continuously wind the
> film back and forth from one reel to another. At recommended winding
> speed of 2 turns per second, a complete wind of one 50-ft. Super 8 film
> would be about 45 seconds from one end to another. For 100-ft spool of
> 16mm (or two Super 8 films stapled together) the time would be one
> minute. At 200 ft., time would be 90 seconds.
>
> IMPORTANT:
> 1. Emulsion should be face out.
> 2. Unless Prebath PB-3 is used when film is first submerged, tilt the
> tank and pour in enough water so that the reel with no film is wet and
> reel with film is dry. Then wind dry film onto wet reel so that emulsion
> is uniformly made wet.
>
> PROCESSING STEPS:
> I do not have recommendations for developing Ektachrome film but for
> developing B&W films like Tri-X Reversal 7278 or Plus-X Reversal 7276,
> use the following processing steps:
>
> SOLUTION and suggested NUMBER OF WINDS AT 68F (20C):
> FIRST DEVELOPER: 12 (Or 8 at 80F--This is the most critical step.
> Decrease number if fully processed films are consistently too light;
> increase if too dark.)
> RINSE: 4 (change water each time)
> BLEACH: 10 (8 at 80F)
> CLEARING BATH: 8 (6 at 80F)
>
> Now remove cover of tank, add water, and re-expose film under a bright
> 200 to 500 watt light or in sunlight for two to three complete winds.
> Cover tank and continue:
>
> SECOND DEVELOPER: 8 (6 at 80F)
>
> You may now rinse film (5 winds running water) and dry, OR if you want
> to harden emulsion and make film less prone to scratches (recommended if
> the film is expectd to have heavy usage) add the following steps:
>
> RAPID FIXER: 2
> RINSE: 2
> HYPO CLEARING AGENT: 2
> RINSE: 5 (running water)
> PHOTO-FLO (optional):2
>
> To dry film, string a line across the room and loop film over and over
> the line, emulsion side up, for uniform drying. Spool onto projector
> reel emulsion side out.
>
> SUGGESTED SOLUTION FORMULAS:
>
> FIRST DEVELOPER: Add 9.5 grams of sodium thiosulfate to 1 liter of Kodak
> D-19 developer regular strength.
>
> BLEACH: To one liter of water add 9.5 grams of Potassium Dichromate and
> 12 ml of concentrated Sulfuric Acid.
>
> CLEARING BATH: To one liter of water add 90 grams of Sodium Sulfite.
>
> SECOND DEVELOPER: Use standard paper developer like Dektol or Polymax T
> regular strength.
>
> FIXER: Use Kodak Rapid Fixer or similar.
>
> HYPO CLEARING AGENT: Use Kodak Hypo Clearing Agent, or similar.
>
> PHOTO-FLO: Use Kodak Photo-Flo or similar.
>
> These solutions can also be used to make B&W slides from almost any 35mm
> B&W film. The recommended starting point times for a standard
> (non-rewind) tank at 20C (68F) is:
>
> FIRST DEVELOPER: 6 min.
> RINSE: 2-5 min. (change water frequently)
> BLEACH: 1-2 min.
> CLEARING BATH: 2 min.
> RINSE/RE-EXPOSE (You can't overexpose at this point)
> SECOND DEVELOPER: 5 min.
> RINSE/FIX/DRY normally.
>
> As a general rule, just remember:
> If too dark, increase time or temp. of first developer.
> If too light, decrease time or temp. of first developer.
>
> TO ORDER HARD-TO-FIND CHEMICALS call Photographer's Formulary toll free
> at 1-800-922-5255. (Note: They only sell sulfuric acid in a 48 percent
> solution so you will need to use 25ml for a liter of bleach instead of
> the 12ml you would use of concentrated solution.) If you want to get
> really fancy, try some of their many toners, intensifiers, or reducers
> on your films or transparencies--experiment first with unwanted films
> since you don't want to risk ruining your good films.
>
> DISCLAIMER: Potassium Dichromate and Sulfuric Acid are hazardous
> chemicals which should be treated with extreme care and handled as
> hazardous waste. If in question, the bleach formula should be made by a
> qualified chemist. Also, bleach does not keep as well as the other
> solutions when mixed. For best keeping, you may want to add the
> potassium dichromate to one-half liter of water to make BLEACH PART A
> and the sulfuric to a separate half-liter of water to make BLEACH PART
> B. The two then are mixed together in equal amounts just prior to usage.
>
> ADDITIONAL TIPS:
> 1. By adding an optional rinse between the bleach and the clearing bath,
> you can probably extend the useful life of the clearing bath. But for
> most consistent results always use fresh chemistry.
> 2. If highlights appear to be not fully reversed (I.E. gray image where
> there should be white) the bleach is exhausted or you need to increase
> bleach time.
> 3. If yellow stain appears anywhere in film, clearing bath is exhausted
> or you need to extend clearing bath time.
> 4. If fixer erases part of the final image, you did not fully re-expose
> or redevelop the film or your redeveloper is exhausted.
> 5. To use the G-3 tank for negative processing, use regular D-19, then
> fix, wash and dry normally.
> 6. For high contrast applications (such as titles or line work) use
> Kodalith developer in both the first and second development stages, or
> as a negative developer.
>
> Best of luck--let me know how you come out.
> Ed Inman -- E-mail -- edinman@teclink.net

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                                END OF FAQ PART 3
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