Basic Film Blowup Workflow General Film Blowup Information Film Blowup FAQ's

Basic Film Blow Up Workflow

The following workflow is for the basic steps needed for a film blowup done at DuArt through the film optical department.

The list does not necessarily encompass all of the steps needed for a blowup, nor does the order of the list remain constant.  There may be steps not listed here that are done at other facilities, but are needed for completion.  Each film may require additional services depending on optical effects needed, multiple original source materials and other creative decisions.

1-      First silent answer print   16mm / Super 16mm (If needed additional corrected answer print)

2-      Interpositive   (B&W -Fine Grain Master / Pan Master)

3-      Dupe negative (Internegative)

4-      Video transfer of film from a workprint, interpositive or dupe negative for sound mix and/or sound sync check

5-      Sound Mix

6-      Manufacture 35mm optical sound track negative

7-      Line up track

8-      35mm Checkprint  (If needed additional corrected checkprint)

Film Blow Up 16mm / S16mm to 35mm

General Information:

*  The first step in the blowup is making the first 16mm / Super 16mm answer print.  If the project is edited electronically, this is usually the first “look” at the cut project on film. When the negative is submitted to the laboratory the film is set up and cued for printing with DuArt’s frame count cueing system allowing the timer to insert timing for each scene.  The timing is based on discussions with the filmmaker and timer during a preliminary viewing of the cut on video.

 During screening of the first answer print the director and cinematographer will review density and color balance issues and suggest corrections to the timer.  In addition this is the opportunity the filmmaker has to make sure the 16mm / Super 16mm film does not have excessive dirt or other defect anomalies before the film is blown up.  It may be necessary at this time to make decisions about how to handle any scenes that may be problematic.  Due to the nature of the film product white “sparkle” is not uncommon especially after handling of the film through the conforming process.  The film is cleaned in the laboratory several times throughout the process, although there can be anomalies in a film product that are incorporated into a blowup.  There is a greater acceptability factor of “dirt” in a projected film element than in a video release.  For video mastering the film can be “dust busted” for the video versions. 

*  Understanding the aspect ratio of how a film was intended to be viewed is important.  There can be many interpretations, therefore it is important to convey to the laboratory your intentions. 

For Super 16mm the aspect ratio is 1.69:1 and the film is usually blown up to a 1.66:1 ratio.  The film can then be screened in 1.66:1, which is a common European ratio, or it can be masked off in a projector cutting the top and bottom slightly to 1.85:1, which is the common United States ratio. 

For regular 16mm the possibilities are greater.  The aspect ratio for 16mm film is 1.33:1.  It can be blown up to use the full aperture area of the 35mm film and screened at a 1.33:1 ratio keeping all of the information.  Some theatres may not be able to accommodate a 1.33:1 35mm ratio.  The 16mm film can also be blown up keeping the full 16mm aspect ratio 1.33:1 within a 1.85:1 35mm ratio. This is uncommon and the film will have a black area to the right and left screen. 

The most common scenario allows for the possibility of vertical image scanning favoring the top or bottom of the 1.33:1 16mm frame. The film is blown up to 1.66:1 cutting off the top and bottom information of the regular 16mm image and then the print can be projected at either 1.66:1 (European) or 1.85:1 (U.S.) aspect ratio. 

*  Optical effects created in offline or online editing reproduced through the film process (optical camera or contact printing) may not appear the same as displayed on a computer monitor.  An effect done on computer based editing systems are linear, but film may not reproduce the same due to many non-linear factors in the film process including exposure of the original and intermediates, inherent contrast of the optical equipment, scene content and contrast of the photographed image.  Psychological factors in the projected image compared to a computer monitor may also play a part in the look of an effect.

Some effects manufactured on different printing machines may give a different appearance.  This may be evident for 16mm answer prints, which are done on contact printers compared to a blowup exposed through optical lenses.   Effects such as dissolves on some scenes, may seem to appear different because of this and an effect can even appear different when created at different stages of a blowup.

*  Dupe negatives from a blowup process may have splices due to head and tail credits that are cut into the dupe negative, or other elements such as tape to film negatives, lower thirds, optical negatives that are spliced in the dupe, or redo shots because of problems.  It is important to be aware of the deliverable requirements from a distributor.  If required it may be necessary to make a second dupe negative from a blowup interpositive, which could then be splice-less if all the films elements exist in the interpositive.

*  To ensure that a complete interpositive can be assembled, it is recommended to make interpositives of all negative elements created, even if they are cut directly into the dupe negative (i.e.: digitally created 35mm original negatives, head and tail credits, lower thirds, etc.).  These interpositives can then be conformed together with the other interpositive elements to create a conformed and complete interpositive.

*  All intermediate blowups elements are made with acetate base stock to facilitate splicing of the different elements.  If you have requirements for polyestar dupe negatives you should budget for a second dupe negative.

*  Timing of a blowup project is required at each step.  The original negative should be timed so that the information is exposed into the interpositive fairly close to the final look of the film.  Sometimes corrected answer prints may be useful especially if scenes are problematic due to unusual negative exposures such as day for night, black and white negative cut within a color project or for non-standard cross-processed reversal “negative.” 

(Note that when these original films are conformed with color negative, they should be conformed as separate rolls.  Since black and white and cross-processed reversal originals do not have the orange mask that is inherent in the base of color negatives, those rolls have to be printed with a special filter setup to emulate the orange negative mask.)

At the final dupe negative stages corrections generally are still required to fine tune the timing of the 35mm blowup dupe negative.  The first checkprint is reviewed with the filmmaker and instructions are given to the timer for corrections to be made into a second (corrected) print if required.

If you would like more information on blowups, download our Shooting 16mm and Super 16mm for Blowup to 35mm brochure

16mm Optical Blowup to 35mm  FAQ’s

Why do I need a 16mm / Super 16mm answer print?

-  It is important to make a print in 16mm / Super 16mm to check the condition of the negative, make sure the film is cut correctly, and correct the timing to be built into the Interpositive.  The intermediate stocks are very expensive, so it is better to find and solve problems before you make the interpositive.

What is the longest reel length that my film should be cut?

-  The 16mm cut negative reel changes should be less than 800’.  When the film is blown up the 35mm the length will then be under 2000 feet.  35mm lengths can be calculated as 2 ½ times the 16mm length.  Intermediate raw stocks are supplied in lengths up to 2000’.  It is not recommended to make reel lengths longer than 35mm 2000’.  If your film is cut in longer than standard length, the interpositive and dupe negatives will have to be made with a “pick up” which will then be spliced together. 

Why must the negative matcher keep reversal cross processed or black and white negatives on separate rolls?

-  Color negative films have an orange mask inherent in the base of the negative.  This orange mask is needed to print onto color print stocks.  Black and white negative and cross processed reversal films must be kept in separate rolls for both A+B printing or single strand conform in camera because they do not have the orange “mask” and a special filter must be inserted for the printing of those rolls to emulate the mask. 

What are standard lengths for dissolves and fades in the laboratory?

-  Standard dissolve/fade lengths are:  16,  24,  32,  48,  64,  and 96.   The film maker should be aware that non standard lengths can be accomplished but the effect would not be a standard fader effect, and may have to be made separately, possibly digitally, which would be a higher price structure.

In my film I am using 16mm, Super 16mm, 35mm and video originals.  How do I incorporate them all together?

-  Increasingly filmmakers are using a mixture of different formats including video source material.  Before cutting a negative, clients should schedule a joint meeting with the Digital and Film Service Managers along with editor and the negative conformer to discuss the entire job.  Because each film is unique, the method of incorporating can be different for every film. 

If different elements dissolve or fade between each other, options need to be discussed on how the effects will be handled.  Straight cuts are easier to handle between different elements.

Why is it better quality to make an interpositive for blow up in 35mm instead of 16mm?

-  Even with today’s high quality intermediate stocks there will always be some loss of information when duplicating original negative to an intermediate, therefore for the better quality, the 16mm information should be exposed first to the larger format (35mm) to retain more of the information.  This will give a finer grain image than if a 16mm interpositive is made and then blown up to 35mm later.

What is the difference between A+B printing and single strand conform in camera?

-  In an A+B cut the length of the scenes are cut to exact length (plus recommended four frames overlap if zero cut).  The normal dissolve and fade effects will be seen in the answer print.  Therefore in A+B 16mm answer printing the color timing for the dissolve will be seen and can be corrected accordingly. 

In a single strand cut, for a conform in camera, the scenes are cut with handles and spliced in one strand.  The normal dissolve and fades are not seen in the 16mm answer print, they are created in the film interpositive stage. 

For conform in camera the slow motion, fast motion and duplicate shots can usually be cut in the single strand and programmed for printing with the normal footage.  In an A+B cut any effects (except normal fades or dissolves) cannot be cut in the A+B rolls. The negative for the effect to be created should be submitted as a separate roll and will be created separately for cutting into the interpositive later. 

In an A+B cut the 16mm print, if all the effects and titles are included or slugged to length, is usually a correct representative of the length of the final film.  The 16mm A+B print may be used for sound mixing or to check the sound sync.  In a conform in camera the scenes in the 16mm answer print are longer than the actual film and will not show the effects such as slow motion or speed up.  The conform in camera 16mm first answer print cannot be used for the sound mix or sound sync check.

It is recommended that you discuss options with your negative cutter also of the advantages and costs of each method from the negative cutters point of view.

Why should I conform my film as a single stand “conform in camera” instead of A+B?

-  Each film has different issues and it is a difficult decision for the film maker.  Discuss the options with your negative cutter as well as with the laboratory.  Some films it may be an advantage to cut the film single strand conform in camera if there is a possibility of re-cuts or different versions required.  Also if there are a lot of stretch printing, skip printing effects, or dupe shots it may be beneficial to cut as a conform in camera as the effects can be programmed by the negative cutter in the main program.  In A+B those effects would have to be made separate from the A+B.

A+B zero cut printing can be advantageous if the film is simple and straight forward, with little effects other than dissolves.  In A+B conforming the color timing of the dissolves will be seen in the answer print, but in a conform in camera they will not be seen on the screen until the final blowup checkprint.

In either case the customer must exam the best for their film, discuss the film with the negative cutter and the laboratory and make the final decision of the method of cutting best for their film.

When should I have my film conformed as an A+B straight cut instead of an A+B zero cut with 4 frame overlaps?

-  Straight cutting is usually done with regular 16mm negatives if the filmmaker decides to screen prints from the original negative in 16mm with sound, or if the film maker chooses to make a 16mm contact interpositive.  The blowup can then be made as an optical 35mm dupe negative.

Note:  Straight cut negatives blown up in the 35mm interpositive stage may exhibit a jump at splices.  If the 35mm blow up interpositive you use to create your video master was made from a straight cut A+B negative, your video master may not meet the stricter video broadcast standards.  Edit box services may be required to correct the possible vertical motion caused by jumping splices.

What is “zero cutting”?

-  A zero cut is a quick closing or opening of printer valves that control exposure onto a film stock.  “Zero cutting” is used in A+B blowups with four-frame overlaps at cuts to eliminate the possibility of jumping splices in a blowup and creates a clean negative at a scene change. 

For A+B contact printing the “zero cut” on an outgoing shot, while the quick opening of the printer valves on an incoming shot will create what looks like a film cut, or one frame “dissolve.”   On optical printing machines (for a blow up to 35mm) the “zero-cut” method of A+B printing, with a minimum four-frame overlap, eliminates the possibility of a noticeable jump at scene changes. 

Note: Contact prints with sound cannot be made directly from Super 16mm negatives, so there is not generally a need to cut in conventional A+B straight cut format, so “zero cut” is usually recommended for Super 16mm.  Although the choice to “zero cut” or “straight cut” a regular 16mm negative is the filmmakers decision depending on their requirements for the film.

Why will my scene changes jump on an optical printer when I make a blowup interpositive from an A+B straight cut film?

-   The effect of jumping splices may happen if the thickness or pitch between splices is not correct.  The pitch of the splice must be identical to the pitch elsewhere or there will be a vertical jump in the picture at the scene change.  This is because registration pins on 16mm full immersion optical wet gates are one or two perforations away from the frame being exposed.  Thus, the position of the frame being printed is established by the perforation on the opposite side of the splice.  Improper position of the first 1 or 2 frames after a splice causes a jump – an adjustment – when the pin registers.  This problem is not as apparent when you make a 16mm contact print from your A+B original.  This is because the 16mm continuous contact printer has sprocket teeth, which register the film and raw stock at the area, which is exposed. 

When splicing, the conformer must physically check the splicer to be sure there is correct distance between the pin positioning the black leader and the pin positioning the negative.  

If the negative is cut with a minimum of 4 frame overlaps and use the zero cut method there should be no jumping splices because the first 1 or 2 frames after a splice are not exposed.

Why do I need to check my sound sync when I have already mixed?

- In electronic editing from video transfers, the edits do not have a frame for frame relationship to the original film.  There may be a discrepancy of which frame is actually used in the final cut, therefore it is recommended that the final sound check for sync is done only after there is an actual film element to check the sound against.  In some cases this may be a 16mm / Super 16mm first answer print if it has all the shots and titles included in the film.  More likely, the interpositive will be the more complete element, so this is usually what is transferred for the sound sync.  Another option would be to make a transfer for sync check from a first silent 35mm checkprint from the 35mm dupe negative.  Each film may be different as to when the filmmaker chooses to make the sound sync check.

Why is a video transfer from a completed element good to be used for a sound sync video check, and not the electronically edited version of the film?

- Because the completed film element is a continuous transfer with no electronic cuts or edits made that may compromise the frame-to-frame relationship for an accurate sync check.

Do effects created on an Avid look different when they are created on film?

- Yes they might, because an electronic effect is linear, but when printed the film does not always react linearly.  Fades or dissolves may look shorter on film.  Effects are also dependent on the scene content, density and exposure, contrast and other aspects of the scenes involved.  A films’ perspective viewed on a video monitor often looks different when projected on a large screen.

At what speeds can I slow down or speed up a scene in a film blowup?

- Slow down (slow motion-stretch printing) or speed up (fast motion – skip printing) as a printer optical effect can only be done at rates that are a mathematical combination of actual frames.  For example to slow down a scene twice as slow, print each frame twice. 

What is vertical image scanning?

- There are times when cropping a regular 16mm 1.33:1 image equally at top and bottom for a blowup for 1.66:1 aspect ratio is problematic because to do so would crop out important image information.  In this case, the 35mm blow up interpositive can be made using vertical image scanning.

Vertical image scanning is adjusting the film plane up or down in the optical camera for a 1.66:1 optical blowup to expose more of the top or bottom of the regular 16mm frame. 

This is only applicable in regular 16mm (not Super 16mm) because the image area in 16mm is 1.33:1 which is not using the top or bottom of the film frame, therefore it is possible to scan up or down to give more head room or more from the bottom of the frame.  Super 16mm cannot be scanned because the entire area of the Super 16mm frame is used to make the 35mm blowup also to 1.66:1 ratio.

What is the normal aspect ratio for 35mm films?

- The aspect ratio for most 35mm films screened in the United States is 1.85:1.  Films can be screened at other ratios, such as 1.33:1, but may be limited to certain theaters.  35mm films in Europe are normally screened at 1.66:1, although this should be researched by the filmmaker for the country where the film will be shown.  Blowups made to 1.66:1 are slightly cropped by the projector at the top and bottom down to 1.85:1 in the United States.  When the film is originally shot the cinematographer should take into account these scenarios.

What aspect ratio are films blown up to?

- Blowups are done to our client specifications.  Blowups from Super 16mm are generally blown up to 1.66:1.  Blowups from Regular 16mm can be blown up to 1.33:1 or if scanned to 1.66:1.  Please discuss your needs with the laboratory technicians.

Can I make my film using the full 1.33:1 aspect ratio of the 16mm original?

-  It is possible to make a blowup using the full 16mm aspect ratio of 1.33:1.  The film can then be screened in 1.33, or masked off in the projector cutting off some of the top and bottom of the frame to 1.66, or 1.85 ratio.  Note that not all theaters are set up to project at 1.33:1 which may result in limited theatrical release.  Alternately a 16mm film can be blown up using the full 1.33:1 16mm aspect ratio within the 35mm 1.85:1 area although there would be a black border on the right and left side of the film.

Note: A black “border” or mask that is produced through the film process, but not masked off in a projector, will appear soft at the edges and may show minor unevenness of the mask or “hair in the gate” issues of an optical camera.  In addition the black levels may not match the surrounding areas outside the projected image.

A ratio of 1.33:1 is generally only for 16mm originals; Super 16mm has a ratio 1.66:1.

My film needs to be screened both for 1.85:1 and 1.66:1, how do I do this?

-  Masking for 35mm films is done in the projector and with the curtains in the theater.  The projector has a matte inserted that blocks the picture to the desired ratio, which gives a soft out of focus edge around the picture, the curtains are drawn slightly smaller which gives a sharp edge to the picture mask. 

In a scanned 16mm or super 16mm blowup the image is also masked in an intermediate stage to create frame lines so that when projected the theater can use either a 1.66:1 mask or 1.85:1 matte in the projector gate.  Note that of course when screening 1.85:1 there will be more cut off top and bottom of the frame.

What are changeover marks?

-  Changeover marks are cues on a film to give a projectionist the signal that the end of the reel is near to start the next reel of the film.  There are generally two sets of 4 cues.  The first set, starting at 12 feet 5 frames from the last frame of the reel, tells the projectionist to start running the next projector.  The second set, starting at 1 foot 9 frames from the last frame of the reel, is when the projectionist closes the dowser cutting the light on one projector simultaneously while opening the dowser on the other projector, effecting a seamless reel change.   When film reels are joined together for plattering in a theater the reel changeover cues are not used. 

It is not recommended that an editor use a fade out at the end of a reel as it difficult to tell where the actual last frame of the reel is during a fade.  It may cause a shot to be cut short or last too long if the actual last frame of the reel is not calculated correct. 

In prints from original negatives the changeover cues are made in each print making a white or light colored cue mark.  Original negatives are not cued, only the print.  If a dupe negative exists, the cueing is permanently done into the dupe negative.  Prints made from a cued dupe negative are usually a darker color. 

My film has some white sparkle, what should I do?

-  Any film product can have defects as the photographic process is not a perfect medium.  The film emulsion can attract and hold dirt, although steps are taken in all phases of the laboratory process to minimize dirt.  In today’s digital world the problem is more prevalent than in the past because a video image does not have the same properties as film and film makers are accustomed to the “dirt free” digital world. 

After screening the 16mm answer print it must be analyzed to the extent of the dirt and decide what action to take before the film is blown up.  A small level of dirt must be expected because it is impossible to have a dirt free film product.   Larger pieces of dirt can be analyzed by the laboratory to determine how to resolve the problem.