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Bleach bypass negative to telecine


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#1 David Cavallo

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Posted 09 November 2006 - 01:01 AM

Just screened the dailies for a Super 16 short film I shot recently on Fuji Eterna 400T 8683, and was rather surprised by the results. We'd done skip-bleach on the negative at the lab (which was then telecined to DVCAM), and after hearing strong warnings from another DP/various cautionary postings online during pre-production, I'd been expecting (and had prepared for) a fairly radical look.

Unfortunately, the dailies (projected from the tapes onto a large screen at school) didn't have the black blacks, blown-out highlights and heavy desaturation we'd been hoping for and been told about--in fact, the image is pretty flat and dull. (Regrettably, although I had strongly advised it, there had been no time and money for a test.) While the colors ARE a little desaturated, but this seems like a characteristic of the Fuji stock's soft pallete and the art direction, and everything else looks like a "normally" processed negative.

Now I'm wondering if this is the fault of the way I exposed the film--if I was TOO careful. I rated the stock normally (400 on my meter) and, because of the warnings I'd heard, basically shot it as if it was reversal--where I wanted to retain detail, I kept things no more than 1/2 stop over key on my highlights, and no more than 2 stops under for my shadows.

Of course if I know that if I'd been exposing this way for something that wasn't bleach bypass, the result would be a flat negative, low-contrast, and poor saturation--but with the skip-bleach shouldn't I be seeing something more extreme, even with this low-con lighting approach? Is it possible that the telecine colorist reduced the effect? Or that the lab promised something and didn't deliver?

Unfortunately I can't yet post anything from the shoot, but here's a specific example: Shot a few sequences in a *white* bathroom, and lit with flat, soft light about 1/2 stop over my shooting stop of T2.8. I was hoping to lose detail on the white tile wall in the shower, almost blow it out, but instead I got detail--and a murky grayish wall. And in a bedroom, areas metered at 3 stops under (where I'd hoped things would go black) instead showed plenty of detail--heck, they almost look LIT.

So, if anyone has had a similar experience, or can offer advice, I'd love to hear about it. The director and I are curious as to how we could have been so far off the mark with our intended look. We can certainly make adjustments in post on the NLE, it's not a catastrophe--things are flat enough that we could boost contrast in post--but it's not what the production paid for.

Many thanks in advance,
David
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#2 Dominic Case

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Posted 09 November 2006 - 02:59 AM

Were there any instructions for the transfer colorist?

It sounds as though the telecine facility has done its best to "rescue" your footage and bring the contrast scale back to what they think is "normal".

The murky greyish wall with more detail than you expected sounds like an almost blown-out white that has been pulled right down.

The detail in the blacks was probably there all along: shadows are the least affected by bleach bypass, they normally block up when you print down, or if you underexpose to counterbalance the blown highlights.
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#3 A. Whitehouse

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Posted 09 November 2006 - 04:25 AM

Just screened the dailies for a Super 16 short film I shot recently on Fuji Eterna 400T 8683, and was rather surprised by the results. We'd done skip-bleach on the negative at the lab (which was then telecined to DVCAM), and after hearing strong warnings from another DP/various cautionary postings online during pre-production, I'd been expecting (and had prepared for) a fairly radical look.

Unfortunately, the dailies (projected from the tapes onto a large screen at school) didn't have the black blacks, blown-out highlights and heavy desaturation we'd been hoping for and been told about--in fact, the image is pretty flat and dull. (Regrettably, although I had strongly advised it, there had been no time and money for a test.) While the colors ARE a little desaturated, but this seems like a characteristic of the Fuji stock's soft pallete and the art direction, and everything else looks like a "normally" processed negative.

Now I'm wondering if this is the fault of the way I exposed the film--if I was TOO careful. I rated the stock normally (400 on my meter) and, because of the warnings I'd heard, basically shot it as if it was reversal--where I wanted to retain detail, I kept things no more than 1/2 stop over key on my highlights, and no more than 2 stops under for my shadows.

Of course if I know that if I'd been exposing this way for something that wasn't bleach bypass, the result would be a flat negative, low-contrast, and poor saturation--but with the skip-bleach shouldn't I be seeing something more extreme, even with this low-con lighting approach? Is it possible that the telecine colorist reduced the effect? Or that the lab promised something and didn't deliver?

Unfortunately I can't yet post anything from the shoot, but here's a specific example: Shot a few sequences in a *white* bathroom, and lit with flat, soft light about 1/2 stop over my shooting stop of T2.8. I was hoping to lose detail on the white tile wall in the shower, almost blow it out, but instead I got detail--and a murky grayish wall. And in a bedroom, areas metered at 3 stops under (where I'd hoped things would go black) instead showed plenty of detail--heck, they almost look LIT.

So, if anyone has had a similar experience, or can offer advice, I'd love to hear about it. The director and I are curious as to how we could have been so far off the mark with our intended look. We can certainly make adjustments in post on the NLE, it's not a catastrophe--things are flat enough that we could boost contrast in post--but it's not what the production paid for.

Many thanks in advance,
David


A Negative Bleach Bypass would have affected the shadows least of all. I have had similar experiences with telecine transfers which I couldn't sit in on and a use of under exposure where the footage has come back flat but it must have been quite a bit of work to grade out a bleach bypass. May I suggest it could have been the colourist looking to play it safe knowing that the transfer was being made to DVCAM? Was it a best light? Did you provide Grey cards and how were they exposed? 1/2 stop in the highlights and 2 under sounds pretty flat to me and the handleful of times Ive shot with 8683 Ive found it to have enormous latitude and a very soft and flat look. If you still have the negative can I suggest it may be worth looking at it on a light bench? Why was the decision made to bleach bypass the neg? Could the money have been spent to achieve a similar effect in your telecine session? I have never been able to convince any project to let me try bleach bypass even for a test and my local lab has always been fairly anti even the proposal (even when trying to push). I would be interested to see the results. Hope this helps,

Sasha
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#4 matt cooke

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Posted 09 November 2006 - 05:21 AM

Hi,
I think that Dominic is correct. Sounds like the colourist 'corrected' your rushes during the TK. This is not a mistake on the lab's part, unless you had given them specific instructions. I think it important to attent the TK, especially if you are trying out things that are un-tested. This reduces confusion if the results that you get are not what you expected and allows you to communicate your intentions to the colourist.
Given the resultant added density that the bleach bypass process gives you I find that the best results are obtained by underexposing by a stop. Maybe worth trying next time...
All this being said, the grading process should allow you to re-build the look that you first intended. And although post created bleachbypass effects never quite match up the the real thing you should be able to get reasonably close.
Hope it works out,

Best,

Matt
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#5 David Cavallo

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Posted 09 November 2006 - 02:32 PM

Were there any instructions for the transfer colorist?

It sounds as though the telecine facility has done its best to "rescue" your footage and bring the contrast scale back to what they think is "normal".

The murky greyish wall with more detail than you expected sounds like an almost blown-out white that has been pulled right down.

The detail in the blacks was probably there all along: shadows are the least affected by bleach bypass, they normally block up when you print down, or if you underexpose to counterbalance the blown highlights.


Thank you for your reply, Dominic. I've learned a great deal from your Film Technology in Post Production book, and appreciate your posts in this forum. (Just why I didn't consult the book's section on Bleach Bypass and Silver Retention before my shoot, I don't know...)

But, no, I didn't give any specific instructions to the transfer colorist. The lab we're working with in NYC does consistently high quality work at all stages in the post process, but as students on a miniscule budget, there was no chance of affording a supervised transfer. And, to be honest, I didn't know precisely how to (or that I could) communicate with the telecine colorist. (It's a big lab, and as they're always doing large scale 35mm productions, it's easy for the little guy to get swept away in the rush.) I'd included some little instructions on the actual camera reports--i.e. "don't time out green filtration on this shot"--but not much else.

Another DP I've consulted with reported that the lab in question, assuming that a final tape-to-tape grade will be done at their facility, does the first telecine transfer as flat as possible to preserve as much of the original negative as possible. All of this fits in with your post--makes sense to me. Many lessons being learned today!

But now I need to figure out the most cost effective way to get some of those highlights back...perhaps with some NLE color correction tools that boost contrast, as the final project will likely be output from FCP to Mini-DV or DVD for screening.

Thanks again,
David
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#6 David Cavallo

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Posted 09 November 2006 - 02:57 PM

A Negative Bleach Bypass would have affected the shadows least of all. I have had similar experiences with telecine transfers which I couldn't sit in on and a use of under exposure where the footage has come back flat but it must have been quite a bit of work to grade out a bleach bypass. May I suggest it could have been the colourist looking to play it safe knowing that the transfer was being made to DVCAM? Was it a best light? Did you provide Grey cards and how were they exposed? 1/2 stop in the highlights and 2 under sounds pretty flat to me and the handleful of times Ive shot with 8683 Ive found it to have enormous latitude and a very soft and flat look. If you still have the negative can I suggest it may be worth looking at it on a light bench? Why was the decision made to bleach bypass the neg? Could the money have been spent to achieve a similar effect in your telecine session? I have never been able to convince any project to let me try bleach bypass even for a test and my local lab has always been fairly anti even the proposal (even when trying to push). I would be interested to see the results. Hope this helps,

Sasha


Thank your for your informative reply, Sasha. It seems entirely possible (perhaps likely) that the colorist did their best to, as you say, "play it safe."

I'll try and answer some of your questions:

- The telecine transfer was unsupervised--it's part of a process/telecine package the lab offers students. But I believe they do call this transfer "best light."

- I shot Kodak color separation and grey scale charts (not a grey card, though I had one ready to go and didn't use it. I'm learning that it's very important!) These charts were exposed normal--my shooting stop was T2.8--and I lit them evenly to that stop at the head of each roll.

- The decision to bleach bypass the negative was, ultimately, made by the director. Because we knew there was little chance of a blow-up to 35mm, and thus no IP or IN to bleach bypass, it seemed to him the best way to achieve the somewhat radical look he likes. (I'd presented various alternatives, and suggested caution--a test of the effect/stock--but no time or money for this was available.)

- I don't know much about creating the look in the telecine, but it sounds completely possible, especially on the DaVinci console the lab uses. The concern now (as students) is lack of funds. Perhaps we'll try something in the desktop NLE--FCP has sophisticated contrast controls, I believe.

- The reason I shot so flat with the 8683 was that I assumed (perhaps mistakenly) based on another DPs report, that the skip-bleach process vastly reduces your latitude, to the point that it's almost like reversal. So, I figured that if I lit in this flat fashion, I could rate the stock normally, with the bleach bypass I would get some pretty good contrast anyhow, as well as the desaturated colors and pronounced grain effect. What I wound up with--at least after the telecine--is a flat, dull image that looks to me like poorly exposed normal processing. Ouch. It's a little desaturated (but I think Eterna stocks are already pastel-ish, so it's hard to tell), a little grainy. The blacks ARE a little blocky, but not much else stands out about it.

- We do have the negative. If I look at it on a light bench, what specifically should I look for? Density? Contrast? I've not done it before.

I will certainly post any extracted still frames (before and after post adjustments, hopefully) as soon as I can.

Thanks again,
David
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#7 Dominic Case

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Posted 09 November 2006 - 09:48 PM

If I look at it on a light bench, what specifically should I look for?

Treat the negative very very carefully - you might still want or need to re-transfer. It's the original, it has heaps more information than even a flat telecine transfer.

The negative itself should show you more contrast than usual - very deep blacks (highlights) because there is silver in the image as well as the usual coloured dyes. If you had an infra-red densitometer (unlikely, I know) such as labs used to control print soundtracks, you would find some IR density in the dark parts of the negative (due to the silver) that wouldn't be there in a normally processed negative with no silver. You'll probably be able to see traces of detail in the shadows that is still there in the telecine transfer (as explained, these aren't affected by the bleach bypass process so much as by the corresponding reduction in exposure (which you avoided!).

If the transfer that you have is a "flat" transfer, calculated to capture the full range of information in the negative, then all is not lost. You should be able to block the shadows up with colour correction in whatever system you are using for finishing. Also stretch the highlights back out to white.

The only downside is that the excessively flat transfer will result in a little extra noise when you stretch it out to high contrast. It would obviously have been better if the lab had known what you were doing, so they didn't "undo" all your work.

Still, next time . . .

Actually, next time, why don't you try getting the effect you want in telecine, rather than chemically. Yes, everyone, I KNOW it won't be identical - but there is nothing sacrosanct or fundamental about the effect of chemical bleach bypass. It's just one of a million looks. THere are many other looks that you can get using lighting, art direction, exposure, film stocks etc in conjunction with transfer settings, grades etc.

And you have more control, and you don't have to pay the extra for BB processing.
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