Jump to content

2-perf, 3-perf or 4-perf?


Martin Hong

Recommended Posts

As Mark says, 2-perf was just a shooting format, it was originally blown-up & squeezed in an optical printer to create a 4-perf 35mm anamorphic (CinemaScope) version for printing.

 

As I said most people don't bother calling 3-perf "Super-35" so that term usually applies to 4-perf 35mm.

 

Super-35 doesn't technically have an aspect ratio, it just refers to exposing the Full Aperture width instead of the Academy Aperture width in order to use more of the negative for a widescreen image. So Super-35 could be used for 1.85 or 2.40 movies shooting in 4-perf 35mm. 4-perf 35mm Full Aperture has a 1.33 : 1 aspect ratio.

 

 

>s Mark says, 2-perf was just a shooting format, it was originally blown-up & squeezed in an optical printer to create a 4-perf 35mm anamorphic (CinemaScope) version for printing.

 

I knew this is basic question.

 

After cropping the aspect ratio would be 2.40:1. So why would the image require a blow-up?

 

Is the cropping(2.66:1 to 2.40:1), blowing-up & squeezing happening as single step in optical printer?

Link to comment
Share on other sites

There is no cropping from 2.66 since Techniscope never used the soundtrack area like modern super35 because there would be no way to show it, and involve even more re-engineering of the cameras.

 

As you know Techniscope is 2-perf instead of 4-perf. Now all projection was 4-perf either flat with a wide aspect ratio of 1.85 (or in some cases 1.66 in Europe) or 2.35 in scope(anamorphic lens with 2*squeezed print).

 

And since that, anything wider then 1.85 used the scope lens for projection, the 2-perf negative had to be squeezed and blown up, to go from the 2-perf height to the standard 4-perf height, to be projected as a normal scope film.

Link to comment
Share on other sites

  • Premium Member

What Alex is saying, Matthew, is that original Techniscope cameras had gates that only exposed a 2.35 area rather than exposed the full aperture of 2-perf, which is 2.66 : 1. However, modern 2-perf cameras often expose full aperture. Doesn't really matter whether the gate exposes 2.40 or 2.66, you aren't going to use the 2.66 area anyway.

 

You could call that "cropping" the sides to 2.40 from 2.66 if your 2-perf camera exposes full aperture, but basically you're just composing for 2.40 and using that area in post, so you aren't consciously cropping the image.

 

Today with a D.I. and making a DCP for digital projection, it's not really a "blow up" anymore, you'd just scan the negative and create a 2.40 digital master.

 

But with 35mm film print projection, as Alex says, it's all 4-perf -- either masked in the projector to 1.85 using spherical projection lenses, or stretched horizontally by 2X to 2.40 with anamorphic projection lenses.

 

So the 2-perf 2.40 image has to be blown-up (more or less just vertically, so stretched from 2-perf to 4-perf) to create a 4-perf 35mm anamorphic version. It's considered a blow-up compared to actually shooting in 4-perf 35mm anamorphic, since that's a larger negative area compared to 2-perf.

Link to comment
Share on other sites

  • Premium Member

So in the pre-digital days, when the 2-perfs had to be blown-up to 4-perf for for projection, would that be an example of "optical widescreen," where the black bars were added in the lab to fill in the rest of the area of the 35mm 4-perf?...

Link to comment
Share on other sites

  • Premium Member

No, the 2-perf image was stretched vertically to create a 4-perf 35mm 2X anamorphic (scope) version, so no black bars, it wasn't a 2.40 letterboxed image within 35mm Academy for flat projection.

 

Oh I get, now. Thanks.

Link to comment
Share on other sites

What Alex is saying, Matthew, is that original Techniscope cameras had gates that only exposed a 2.35 area rather than exposed the full aperture of 2-perf, which is 2.66 : 1. However, modern 2-perf cameras often expose full aperture. Doesn't really matter whether the gate exposes 2.40 or 2.66, you aren't going to use the 2.66 area anyway.

 

You could call that "cropping" the sides to 2.40 from 2.66 if your 2-perf camera exposes full aperture, but basically you're just composing for 2.40 and using that area in post, so you aren't consciously cropping the image.

 

Today with a D.I. and making a DCP for digital projection, it's not really a "blow up" anymore, you'd just scan the negative and create a 2.40 digital master.

 

But with 35mm film print projection, as Alex says, it's all 4-perf -- either masked in the projector to 1.85 using spherical projection lenses, or stretched horizontally by 2X to 2.40 with anamorphic projection lenses.

 

So the 2-perf 2.40 image has to be blown-up (more or less just vertically, so stretched from 2-perf to 4-perf) to create a 4-perf 35mm anamorphic version. It's considered a blow-up compared to actually shooting in 4-perf 35mm anamorphic, since that's a larger negative area compared to 2-perf.

 

> However, modern 2-perf cameras often expose full aperture. Doesn't really matter whether the gate exposes 2.40 or 2.66, you aren't going to use the 2.66 area anyway.

 

Does 'Modern 2-perf cameras often expose full aperture' mean the 'full aperture area' in the '2-perf area' ?

 

>But with 35mm film print projection, as Alex says, it's all 4-perf -- either masked in the projector to 1.85 using spherical projection lenses, or stretched horizontally by 2X to 2.40 with anamorphic projection lenses.

 

How would the 2-perf image look on a 35mm print? Is it squeezed image for 2.40:1? Then does that image projected using De-anamorphic lens?

 

>So the 2-perf 2.40 image has to be blown-up (more or less just vertically, so stretched from 2-perf to 4-perf) to create a 4-perf 35mm anamorphic version. It's considered a blow-up compared to actually shooting in 4-perf 35mm anamorphic, since that's a larger negative area compared to 2-perf.

 

Does 'Blow-up' means printing the image blown-up onto a 4-perf 35mm print film or projecting the image which is fit into 2-perf area in a print film onto screen?

 

Does '4-perf 35mm anamorphic version' mean a squeezed 2.40:1 image onto a 35mm film?

How much area the image occupy in print? Would it utilize entire 4-perf area or a image fit into 2-per area?

Link to comment
Share on other sites

  • Premium Member

"Full Aperture" just means the largest possible usable area of the negative for whatever format you are talking about -- sprocket row to sprocket row in one direction and the frame lines in the other direction.

 

The blow-up + squeeze from 2-perf spherical to 4-perf anamorphic maybe would be more clear to look at these illustrations:

2P_to_4P.jpg

 

In this drawing of the 2-perf frame, this is the classic Techniscope format where the camera did not expose image into the soundtrack area (the grey stripe area on the left edge) since it didn't need to, because if it did, that would be a 2.66 : 1 image.

 

The 4-perf 35mm anamorphic format does not use the soundtrack area on the left for picture either, since it is a projection format (meaning there is a soundtrack on the print.)

Link to comment
Share on other sites

"Full Aperture" just means the largest possible usable area of the negative for whatever format you are talking about -- sprocket row to sprocket row in one direction and the frame lines in the other direction.

 

The blow-up + squeeze from 2-perf spherical to 4-perf anamorphic maybe would be more clear to look at these illustrations:

2P_to_4P.jpg

 

In this drawing of the 2-perf frame, this is the classic Techniscope format where the camera did not expose image into the soundtrack area (the grey stripe area on the left edge) since it didn't need to, because if it did, that would be a 2.66 : 1 image.

 

The 4-perf 35mm anamorphic format does not use the soundtrack area on the left for picture either, since it is a projection format (meaning there is a soundtrack on the print.)

 

Thank you David. Now I got it.

Link to comment
Share on other sites

  • 3 years later...

According to these for 1:1.78 ratio you can use just 3 perfs 

I'm planing to shoot with an ARRI 535B on Academy format on 1.78 ratio .. But i don't know yet if the camera would be on 3perfs or 4perfs 

What would be the ideal ? The 535B to be on 3 or 4 perfs ? Which mode will give me better image quality ?

Also if i shoot in 3perf for film economy .. would be most difficult (and expensive) for post production to print it for projection on standard 35 film ? 

Thanks again !!

 

Perf-2.jpg

Perf-3.jpg

Edited by panagiotis agapitou
Link to comment
Share on other sites

  • Premium Member
4 hours ago, panagiotis agapitou said:

According to these for 1:1.78 ratio you can use just 3 perfs 

I'm planing to shoot with an ARRI 535B on Academy format on 1.78 ratio .. But i don't know yet if the camera would be on 3perfs or 4perfs 

What would be the ideal ? The 535B to be on 3 or 4 perfs ? Which mode will give me better image quality ?

Also if i shoot in 3perf for film economy .. would be most difficult (and expensive) for post production to print it for projection on standard 35 film ? 

Thanks again !!

There were a hand-full of 3 perf movements made for 535's. 

Most 4 perf cameras are "academy" ratio, which does not use the full width of the negative. The 3 perf cameras are all super 35mm, which DOES use the fill width. So if you do find a super 35mm 4 perf camera, then you'd be using the full height and width of the format, which is good. Obviously you would be cropping the 1.33:1 aspect ratio 4 perf frame to 1.75:1, so might as well shoot 3 perf! 

If you're going back to film and MUST do a photochemical finish, then you should shoot 4 perf. You'd shoot with a 1.85:1 ground glass on the camera for framing and then for projection they'd put a 1.85:1 matte on the projector. Most movies that were shot 4 perf in recent years were made this way. If you shoot 3 perf, it's way easier to do a full digital post because the blow-up from 3 perf to 4 perf can be super expensive and lose quality. It's cheaper to a laser back to film at 2k, which will look crisper then any photochemical finish honestly. 

Link to comment
Share on other sites

  • Premium Member
1 hour ago, Tyler Purcell said:

Most 4 perf cameras are "academy" ratio..

What modern cameras are Academy only? Super 35 was the defacto standard since the 90s, so unless you're talking the 35BL range and older (and many 35BL4s were Super 35 compatible), in my experience most 4 perf cameras are full aperture with an offset PL mount that rotates between Super and Standard. You could put masks in the gate to reduce the aperture, but many people didn't bother and just left the camera exposing the full aperture, since it could be matted later. Switching to Standard was really only done for anamorphic shoots to centre the lens to the Academy frame, but again the gate was often left full aperture.

If in doubt, check that the camera has a PL mount with 1 and 2 engraved in the top right and bottom left corners, to indicate Super/Standard positions. 

Link to comment
Share on other sites

17 minutes ago, Dom Jaeger said:

What modern cameras are Academy only? Super 35 was the defacto standard since the 90s, so unless you're talking the 35BL range and older (and many 35BL4s were Super 35 compatible), in my experience most 4 perf cameras are full aperture with an offset PL mount that rotates between Super and Standard. You could put masks in the gate to reduce the aperture, but many people didn't bother and just left the camera exposing the full aperture, since it could be matted later. Switching to Standard was really only done for anamorphic shoots to centre the lens to the Academy frame, but again the gate was often left full aperture.

If in doubt, check that the camera has a PL mount with 1 and 2 engraved in the top right and bottom left corners, to indicate Super/Standard positions. 

That means i can use 3perf for 1.78 on standard ... right ?

Link to comment
Share on other sites

  • Premium Member
59 minutes ago, panagiotis agapitou said:

That means i can use 3perf for 1.78 on standard ... right ?

In theory, yes, if you can find a ground glass for the camera. 

But you will lose a bit of area. Look at Arri's ground glass catalogue and compare N35 1.78 to S35 1.78:

http://www.arrirental.com/pdf/format_guide.pdf

Link to comment
Share on other sites

14 hours ago, Dom Jaeger said:

In theory, yes, if you can find a ground glass for the camera. 

But you will lose a bit of area. Look at Arri's ground glass catalogue and compare N35 1.78 to S35 1.78:

http://www.arrirental.com/pdf/format_guide.pdf

Thanks !! 

It seems that shooting 1.78 on Academy could only be with 4perf .. 

I'll study the pdf later .. thanks again 

Link to comment
Share on other sites

A little help 'cause i'm new to that .. 

1. Which of these tools i need to shoot 1.78 on Academy on a 4perf 535B ?

2. Can i shoot also 4perf Academy 1.78 on an ARRICAM LT ? (I read that arricam does not support Academy .. only Super35 and i'm a bit confused) 

3. If a can shoot 4perf 1.78 academy on ARRICAM LT .. which tools i need ??

Thanks again ...

 

Screenshot-2019-04-03-18-51-02.png
Screenshot-2019-04-03-18-51-16.png

 

Edited by panagiotis agapitou
Link to comment
Share on other sites

  • Premium Member

Here is the problem... if you're going back to film, then you want an academy gate AND ground glass. This way, when you're making prints, the area for the soundtrack has no information, thus the lab doesn't have to do any work to block that area off in the printer. Lucky for you, on the Arri's it's easy to change the gate and ground glass. 

1)  I'd just look for a 1.85:1 ground glass and an Academy gate for whatever camera you're going to be using. Re-centering of the lens is not necessary, unless the lens used is only designed to cover academy, which is super rare. Remember, the projectors will be matted to 1.85:1, not 1.75:1 so trying to get all of this to work at 1.75:1 is kinda silly. 

2+3) I don't know if the Arricam's can shoot Academy, but I would assume the answer is yes because it's not a big deal. As long as they made the parts (ground glass and gate) then it should work fine. 

Link to comment
Share on other sites

18 minutes ago, Tyler Purcell said:

1)  I'd just look for a 1.85:1 ground glass and an Academy gate for whatever camera you're going to be using. Re-centering of the lens is not necessary, unless the lens used is only designed to cover academy, which is super rare. Remember, the projectors will be matted to 1.85:1, not 1.75:1 so trying to get all of this to work at 1.75:1 is kinda silly. 

 

I want to frame the compositions in 1.78 'cause is now the worlwide standard for modern tvs .. cell phones .. tablet etc 

So The theatrical 1.85 masking is an unavoided compromise ... 

Edited by panagiotis agapitou
Link to comment
Share on other sites

  • Premium Member

You don’t need to hard mask your negative if you just want to compose for 1.78, you just need 1.78 framelines in your viewfinder. However, 1.78 isn’t a projection standard so is this not for print? If this is for print / theatrical release, then use 1.85, it’s nearly the same shape as 1.78. And why are you shooting 4-perf for 1.78 instead of 3-perf?

Link to comment
Share on other sites

  • Premium Member

If you want to make a straight contact print for theatrical projection, then shoot 4-perf and compose for 1.85. Shoot open-matted or at the most, with a 1.66 hard matte, and if you want, you can make the later home video / broadcast / internet versions 1.78 instead of 1.85, it’s just a few more scanlines of extra picture top & bottom.

Or compose for 1.78 and live with the contact print being projected in 1.85, slightly cropped top & bottom.

Link to comment
Share on other sites

44 minutes ago, David Mullen ASC said:

You don’t need to hard mask your negative if you just want to compose for 1.78, you just need 1.78 framelines in your viewfinder. However, 1.78 isn’t a projection standard so is this not for print? If this is for print / theatrical release, then use 1.85, it’s nearly the same shape as 1.78. And why are you shooting 4-perf for 1.78 instead of 3-perf?

Hello David .. thanks for answering !!

1.I want to use the Standard 35mm Academy becouse I'm studying Kubrick's focal lengths and i want to have it excactly like him .. 

2. i think 1.78 on 3perf uses the super35 area   

3. i prefer the 1.78 becouse is the standard for TVs .. Laptops .. cells etc .. there would be a theatrical presentation and i'll put black side bars on the 1.85 projection frame 

Edited by panagiotis agapitou
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...