Jump to content


Photo

bleach bypass again...


  • Please log in to reply
14 replies to this topic

#1 Thomas Cousin

Thomas Cousin
  • Basic Members
  • PipPip
  • 74 posts
  • Cinematographer
  • Paris, France

Posted 04 November 2005 - 02:54 PM

hi,
i know that when you do a BB on the negative, you have to underexpose (take your 500 asa stock at 1000 asa for example) it a full stop when you're shooting.
but is it a true rule that apply all the time ? the additional silver left on the neg will add more density, so the neg will be darker and the positive image will be "lighter". it's true for an "average" image.
but what if i shoot a fairly dark environnement ? with low key, dark paint, dark design, etc etc
would i underexpose my BB neg as well ?

thomas
  • 0

#2 Stephen Williams

Stephen Williams
  • Sustaining Members
  • 4708 posts
  • Cinematographer
  • Europe

Posted 04 November 2005 - 03:06 PM

hi,
i know that when you do a BB on the negative, you have to underexpose (take your 500 asa stock at 1000 asa for example) it a full stop when you're shooting.
but is it a true rule that apply all the time ? the additional silver left on the neg will add more density, so the neg will be darker and the positive image will be "lighter". it's true for an "average" image.
but what if i shoot a fairly dark environnement ? with low key, dark paint, dark design, etc etc
would i underexpose my BB neg as well ?

thomas


Hi,

I think yoi should do some tests with a full BB and a 50% BB.
The negative can't be stored long term, so that could be a big issue.
Is this for telecine or printing?

Stephen
  • 0

#3 Joseph White

Joseph White
  • Basic Members
  • PipPipPip
  • 143 posts
  • Cinematographer
  • Los Angeles, CA

Posted 04 November 2005 - 03:13 PM

more than anything i think it's a matter of taste. most labs (i've only ever done skip-bleach on the neg at fotokem and they said to underexpose one stop) will advise you on the best way to "normally" rate your film when doing skip bleach, but in a way somewhat similar to cross-processing, you don't know 100% what you're getting until you do tests with that particular batch, with whatever degree of it you're doing, or once you sit down with the neg and your colorist. are you planning on doing a 100% process or something more gradual like DeLuxe or Technicolor's processes?

sounds like in your situation your darker tones are going to go way black/dark, i guess it depends on the quality and level of the light that you're keying with. also depends on what 500t stock you're using - 5218 will be more forgiving in this type of situation in terms of latitude than 5279, but I have to say I LOVE the look of 5279 with skip bleach processing.

also depends on whether you're finishing to print or to tape in terms of flexability in grading. the rating suggestions made by labs are guidelines not laws - hell overexpose a stop if you like, its not like the film won't "come out" it'll just be even less saturated, the whites will go even hotter, and you might lose a little grain if you pull it a stop or just print it down.


hope this helps. happy shooting!

Edited by Joseph White, 04 November 2005 - 03:15 PM.

  • 0

#4 Tomas Koolhaas

Tomas Koolhaas
  • Basic Members
  • PipPipPipPip
  • 334 posts
  • Cinematographer
  • los angeles

Posted 04 November 2005 - 03:50 PM

Hi,
I found when doing a bleach bypass that the "rule" of always underexposing the negative is completely subjective! I was only doing a transfer to HD so a few of the issues with BB's didn't really affect me as much.
I was lucky enough to do extensive testing and what I found was that the underexpose rule did not yield the best results in all conditions. We shot interior/exterior day overcast/sunny, and for each condition I found that different levels for the key/fill worked best: I cant remember all the levels but I remember that in the sunny daylight I went 1 stop over on the key and 1 stop under on the fill side of a womans face (reflected readings) and this looked very good, whereas when we shot in overcast light the image looked best under exposed a stop (500 rated at 1000). there were also shots were I let the sky go 3 stops over and these also looked good, and we were shooting bulidings in the shadow at 2 stops under and it also looked great. I guess the moral of this long story is that the one stop under rule is very subjective, and only worked best for me in one condition: overcast daylight. However general things to be wary of when doing a BB process, especially in your case when you are shooting a low-light night scene, is that the blacks become quite considerably deeper, and the highlights blow-out much quicker, so be careful to use enough fill in areas you want to retain detail in and try to balance out the highlights in the scene a bit more than you useually would, other wise you may end up with burnt out highlights floating around in blackness.
Cheers.
  • 0

#5 Sol Train Saihati

Sol Train Saihati
  • Basic Members
  • PipPip
  • 96 posts
  • Gaffer
  • London

Posted 04 November 2005 - 04:05 PM

The main issue here is your leighway with exposure. Usually you can overexpose by two stops and still easily bring the picture back in telecine, however with a BB (taking the stock at ~ twice the speed) this kind of overexposure may leave you without enough information to provide a healthy neg. Play it safe, shoot tests, tests, tests! Make-up, lighting styles, exposure, set design, tungsten, daylight, HMI, flouro, different stocks, different labs - as much as you can afford. If you're thinking of going for a BB, you have to be certain to do it as accurately and scientifically as possible in order to get the results you want; because on the neg..... There's no turning back baby! :D

Edited by djdumpy, 04 November 2005 - 04:06 PM.

  • 0

#6 Stephen Williams

Stephen Williams
  • Sustaining Members
  • 4708 posts
  • Cinematographer
  • Europe

Posted 04 November 2005 - 04:08 PM

because on the neg..... There's no turning back baby! :D


Hi,

Thats not totally true, you can bleach the film later. You will then have a thin negative as you underexposed by 1 stop!

Stephen
  • 0

#7 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 04 November 2005 - 09:41 PM

My experience was that I needed to underexpose more, because the bleach-bypassed negative was quite dense and some colors were hitting 50 on the printer light scale. Now if you want that "hot" look, then don't underexpose.
  • 0

#8 Charles MacDonald

Charles MacDonald
  • Sustaining Members
  • 1157 posts
  • Other
  • Stittsville Ontario Canada

Posted 04 November 2005 - 10:17 PM

The negative can't be stored long term, so that could be a big issue.
Stephen


What happens in the long term? I would think that Bleach bypass would leave you with a "normal" Colour Negative, overlayed with a Silver Black and White negative. The presence of silver should not cause any more instability than the silver soundtrack that used to be on all 35MM prints before they went to cyan tracks. :blink:

NOW cross processing - that may leave you with reduced negative life! :wacko:

Edited by Charles, 04 November 2005 - 10:18 PM.

  • 0

#9 John Pytlak RIP

John Pytlak RIP

    (deceased)

  • Sustaining Members
  • 3499 posts
  • Industry Rep
  • Rochester, NY 14650-1922

Posted 05 November 2005 - 09:37 PM

Kodak does not routinely evaluate the long term stability of "non standard" processing. Yes, some cross-processed reversal films may fade rapidly unless a formalin stabilizer is used by the lab.
  • 0

#10 Stephen Williams

Stephen Williams
  • Sustaining Members
  • 4708 posts
  • Cinematographer
  • Europe

Posted 06 November 2005 - 04:23 AM

Kodak does not routinely evaluate the long term stability of "non standard" processing.


Hi,

That was my problem with BB, the insurance comany would not accept any liability for non standard neg processing!

Stephen
  • 0

#11 Dominic Case

Dominic Case
  • Basic Members
  • PipPipPipPip
  • 1357 posts
  • Other
  • Sydney Australia

Posted 06 November 2005 - 09:43 PM

There is no evidence that bleach-bypassed neg deteriorates quicker than correctly processed neg. The retained silver shouldn't affect the stability of the dyes.

But as John points out, the results haven't been tested as exhaustively as correctly processed neg has.

It's not the same as cross-processing, where reversal stocks need a formalin stabiliser that isn't used for the negative process.

If you rewash bleach-bypassed neg you will get the same results as if you had processed normally to start with. If that includes under-exposing, that's what you get.

If you expose normally and then bleach bypass neg, the printer lights will be up at around 50 - leaving no room for adjustment. If you want a burnt-out look, that's OK, but if you want a dark look, then you really will need to print down, so underexposure is advised. This doesn't appy if you aren't making prints.

If you under-expose you don't run into the problem of milky blacks that you normally do, because the siler makes for a denser image.

If you ask for less than 100% bleach bypass, you may find results are inconsistent from day to day, as the bleach process does not proceed in a linear fashion. You might be lucky, but don't count on it.

Whatever you want from your bleach bypass, you will need to test test test.
  • 0

#12 Thomas Cousin

Thomas Cousin
  • Basic Members
  • PipPip
  • 74 posts
  • Cinematographer
  • Paris, France

Posted 27 November 2005 - 12:42 PM

hello,
thank you all for all the comments.

following the subject, i have one more question.
i probably going to use bleach bypass on the neg on the 7218 for a project very soon.
and i will not be able to have tests. so i am turning to you guys.
what will happen to the latitude of the '18 with such treatment. the latitude will be reduced but in what extent?

i looked at old comparating curves i had (normal neg and bleach bypassed neg), and you seem to lose a lot of latitude. i would say you lose some 2 to 3 stops of latitude.
what would you say about that ? what was your experiences ?
thanks
thomas
  • 0

#13 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 27 November 2005 - 12:48 PM

Hence why you need to shoot a lighting contrast comparison test (between normal and bleach-bypassed footage) before beginning a project where you are doing bleach-bypass.

When doing it to the negative, you mainly gain contrast (lose exposure latitude) in the highlights more than the shadows. Opposite when doing it to the print.

Now if you don't want quite as much contrast increase, you could start with a lower-con film like Fuji 400T or Kodak Expression '29.

I never understand why before doing something risky to the film image, people always preface their question with "I can't shoot tests". Why do something risky WITHOUT a test? Why not do everything humanly possible to shoot a test before saying that it's not possible? I'm amazed at how many people post here and say that they won't be doing tests. I've did tests even when I was in film school. I do tests before I begin every feature, even the lowest-budgeted ones. Don't give up too easily when producers tell you that there's no money for tests. At the very least, see if the lab can show you someone else's tests.

Edited by David Mullen, 27 November 2005 - 12:51 PM.

  • 0

#14 Dominic Case

Dominic Case
  • Basic Members
  • PipPipPipPip
  • 1357 posts
  • Other
  • Sydney Australia

Posted 27 November 2005 - 07:49 PM

i probably going to use bleach bypass on the neg on the 7218 for a project very soon.
and i will not be able to have tests. so i am turning to you guys.

If you can't shoot tests, don't mess with bleach bypass.

Most times, people are appalled by the look of their first tests, but - if they are good - manage to adjust the lighting and exposure to get the result they want - sometimes with several more test runs, sometimes in the second round.

More importantly, blaach bypass is only a process. It's not a look by itself. You combine the processing technique with design, wardrobe, lighting, choice of filmstock, and so on, to get a look. BB has been used by many different cinematographers to get completely different looks.

Asking for general advice about how much to underexpose for BB etc, without giving a very clear and detailed description of the scene, and of the look that you want, is not much use. You might as well ask "I want to use a diffusion filter, which one would you recommend".

Just as one point, note that different stocks behave in diferent ways. In general, higher speed stocks seem to retain more silver, so gain more contrast and lose more latitude.
  • 0

#15 John Pytlak RIP

John Pytlak RIP

    (deceased)

  • Sustaining Members
  • 3499 posts
  • Industry Rep
  • Rochester, NY 14650-1922

Posted 27 November 2005 - 11:12 PM

If you can't shoot tests, don't mess with bleach bypass....



Just as one point, note that different stocks behave in diferent ways. In general, higher speed stocks seem to retain more silver, so gain more contrast and lose more latitude.


Actually, the higher speed stocks usually HAVE more silver halide to begin with, and so have more silver if they are not properly bleached.


I never understand why before doing something risky to the film image, people always preface their question with "I can't shoot tests". Why do something risky WITHOUT a test? Why not do everything humanly possible to shoot a test before saying that it's not possible? I'm amazed at how many people post here and say that they won't be doing tests. I've did tests even when I was in film school. I do tests before I begin every feature, even the lowest-budgeted ones. Don't give up too easily when producers tell you that there's no money for tests. At the very least, see if the lab can show you someone else's tests.


The cost of having to reshoot if the results of a non-standard process are unsatisfactory or unexpected are MUCH greater than the cost of having run simple tests to calibrate your exposure, lighting, and "look". "Penny wise and pound foolish". :rolleyes:
  • 0


Wooden Camera

FJS International, LLC

Willys Widgets

Glidecam

Visual Products

Broadcast Solutions Inc

Technodolly

Rig Wheels Passport

Gamma Ray Digital Inc

CineTape

Abel Cine

rebotnix Technologies

Ritter Battery

Paralinx LLC

Aerial Filmworks

Media Blackout - Custom Cables and AKS

Metropolis Post

CineLab

Opal

Tai Audio

The Slider

Paralinx LLC

CineLab

rebotnix Technologies

Metropolis Post

Wooden Camera

The Slider

FJS International, LLC

Rig Wheels Passport

Opal

Ritter Battery

Willys Widgets

Glidecam

Broadcast Solutions Inc

Visual Products

Tai Audio

Abel Cine

Media Blackout - Custom Cables and AKS

CineTape

Aerial Filmworks

Technodolly

Gamma Ray Digital Inc