Jump to content


telecine image vs film graded image (skip bleach by-pass)


  • Please log in to reply
8 replies to this topic

#1 rajavel

rajavel
  • Guests

Posted 27 May 2006 - 08:54 AM

hi all
recently i had skip bleach by passed the negative for one sequence of a feature film. while telecine'g for edit purposes....we were able to see the saturated colours and the beautiful blue sky in one particular shot. it obviously showed that the negative (after skip bleaching) has registered the blue of the sky on it....but when i took on to the colormaster for the final grading....oops..was disappointed to see or rather not see the blue of the sky...it was completely blown out...of course my guess is that it would have been out of the ZONEs recommended for a skip bleach....
my qn is....how is that if the negative has the blue..why cant i get it on the print after grading??? how can the negative loose its nature?i want that blue i saw in the telecine image! can somebody help me with this.
thanks
rajavel
  • 0

#2 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19760 posts
  • Cinematographer
  • Los Angeles

Posted 27 May 2006 - 11:19 PM

Traditional film finishing is a two-step process -- negative to positive. It's different than scanning or transferring from film negative and electronically reversing it into a positive. I only say that because you have to think of negative as only half of the process -- a certain amount of information on it is DESIGNED to be lost when printing, or else prints would look like negatives -- very flat.

So if there is information on the negative that cannot be brought out in traditional printing, then you would need to do a digital intermediate and manipulate the image off of the negative so that a new negative can be recorded out from the digital file and printed.

With a skip-bleached negative, you have a lot more density in your highlights, and the dyes are polluted with black silver, which is why colors become less saturated. A telecine can manipulate the image to bring out certain colors and counteract the skip-bleach effect, but then what's the point of doing the skip-bleach if you didn't want the desaturation?
  • 0

#3 Filip Plesha

Filip Plesha
  • Basic Members
  • PipPipPipPip
  • 1267 posts
  • Other
  • Croatia

Posted 28 May 2006 - 04:29 AM

David
I don't know how things are with print stock, but if they behave anything like papers, then they are not supose to clip highlights or shadows, but instead apply a strong S curve which gives as much contrast as you like, while compressing highlights and shadows without cliping anything.
But maybe print stocks behaves in a different way, I wouldn't know

Edited by Filip Plesha, 28 May 2006 - 04:30 AM.

  • 0

#4 Filip Plesha

Filip Plesha
  • Basic Members
  • PipPipPipPip
  • 1267 posts
  • Other
  • Croatia

Posted 28 May 2006 - 04:29 AM

double post

Edited by Filip Plesha, 28 May 2006 - 04:31 AM.

  • 0

#5 Sam Wells

Sam Wells
  • Basic Members
  • PipPipPipPip
  • 1751 posts
  • Cinematographer

Posted 28 May 2006 - 10:04 AM

You mention the Colormaster but did you see the print yet ?

A good telecine is a "million dollar Hazeltine" (or Colormaster); it will spoil you in any case I'm sure..

But how is the print ?, and it might take more than one try at it...

Then again David's point is well taken I think..

-Sam
  • 0

#6 Michael Nash

Michael Nash
  • Sustaining Members
  • 3330 posts
  • Cinematographer
  • Pasadena, CA

Posted 28 May 2006 - 04:41 PM

I don't know how things are with print stock, but if they behave anything like papers, then they are not supose to clip highlights or shadows, but instead apply a strong S curve which gives as much contrast as you like, while compressing highlights and shadows without cliping anything.
But maybe print stocks behaves in a different way, I wouldn't know


Print stocks don't compress the entire range of the negative, even with a curved shoulder and toe. They seem to be designed to optimize a normal-looking contrast throughout the range, essentially a longer "straight line portion" compared to negative.

My print experience is pretty limited though, so I don't really know the limits. But I wouldn't expect a print to show the same shadow and highlight response as a telecine transfer.
  • 0

#7 rajavel

rajavel
  • Guests

Posted 29 May 2006 - 12:17 PM

thanks to all. point taken David.
i had it printed yesterday...some shots had a touch of blue...sky. some more
blown out. i need to do it again...again to get it right. will be doing table corrections with this
sequence...and try test bits. let me keep u infomed.
thanks
rajavel
  • 0

#8 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19760 posts
  • Cinematographer
  • Los Angeles

Posted 29 May 2006 - 01:08 PM

David
I don't know how things are with print stock, but if they behave anything like papers, then they are not supose to clip highlights or shadows, but instead apply a strong S curve which gives as much contrast as you like, while compressing highlights and shadows without cliping anything.
But maybe print stocks behaves in a different way, I wouldn't know


Just from practical experience, you lose about a stop at either end (highlights and shadows) in a print off of the negative versus what you can pull out, detail-wise, in a digital grade. Now with a digital grade, you can alter the image so that the output negative can now be printed to preserve more information, for example, by using Power Windows to bring down bright areas, etc. But there is definitely more information on a negative than a print when you're talking about motion picture work.

This is one of the problems cinematographers who shoot mostly for telecine transfer run into -- they are so used to being able to pull out extreme shadow or highlight information off of the negative that if they have to shoot for traditional photochemical post, neg-to-print, they sometimes find that they did not use enough fill light, for example, or that they should have used an ND grad on a sky, etc.

And obviously the higher-contrast printing process you use, for example, using Vision Premier 2393 instead of Vision 2383 print stock, or even more extreme, using a silver retention process to the print like ENR, the more you may have to adjust the contrast ratio on your original photography to compensate.

The gamma and D-max of motion picture print stocks are very high in order to keep blacks looking black when you shine a bright projector light through the print and throw the image on a white reflective screen. To compensate, the contrast of the negative stocks are rather low, and when doing a digital color-correction, you can manipulate that information to enhance certain areas of the frame to make detail more or less visible.
  • 0

#9 Filip Plesha

Filip Plesha
  • Basic Members
  • PipPipPipPip
  • 1267 posts
  • Other
  • Croatia

Posted 29 May 2006 - 03:34 PM

Well, thanks for the explanation. From what you say, it seems that print films have higher relative gamma than photo papers since they sort of blow out the extremes of the range on the negative.

I'm not saying that no papers do that, sure some consumer papers can blow out highlights or block up colors, but the finest of papers, usually increase only the midtone gamma, thus compressing the shadows and highlights relative to the midtones, and making a really soft clip, where information is compressed rather than cut off.

Same goes for scanners. Some scanning software/profiles clip highlights and shadows, while others apply a soft clip retaining all of the information on the negative. One of the main reasons why it is smart to scan negatives as positives then do it yourself in photoshop. With that kind of soft clipping S curve method you can have best of both worlds: high-contrast and use the entire range of the negative all at once.
  • 0


Ritter Battery

Broadcast Solutions Inc

CineLab

Media Blackout - Custom Cables and AKS

Willys Widgets

Opal

Tai Audio

Visual Products

Paralinx LLC

Gamma Ray Digital Inc

Rig Wheels Passport

rebotnix Technologies

Metropolis Post

Aerial Filmworks

The Slider

Wooden Camera

Glidecam

FJS International, LLC

Abel Cine

Technodolly

CineTape

Gamma Ray Digital Inc

Technodolly

Media Blackout - Custom Cables and AKS

Opal

Wooden Camera

Rig Wheels Passport

Abel Cine

CineLab

Willys Widgets

Aerial Filmworks

CineTape

Broadcast Solutions Inc

rebotnix Technologies

Paralinx LLC

Glidecam

Metropolis Post

Tai Audio

Visual Products

Ritter Battery

The Slider

FJS International, LLC