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5245 LUT with 5201 neg.


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#1 martinboege

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Posted 17 February 2006 - 03:13 PM

The question is if someone has done a DATA to FILM using a laser graphics machine, wih the Look up table (LUT) of the 5245, but ussing the new 5201 with the exactly same numbers. I did a test and seems all right (Its a B & W film, so it has a nice contrast. Just wondering if some one has done this before...
Thanks
The second question is: I send the test print and I have to keep putting filters in timing. Some takes are cyan, some red, sometimes I need half points in the timing but they dont have those. Will my Black & White film have always some color?

thanks...

pd I shot in 5222
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#2 Max Jacoby

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Posted 17 February 2006 - 03:24 PM

In regards to your second question, unless you print on black & white print stock there always will be a ever so slight tint in your prints.
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#3 David Mullen ASC

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Posted 17 February 2006 - 03:44 PM

There is no such thing as a half-point correction.

The one argument for doing a D.I. is that at least the output will be timed and hopefully can then be printed at one light, which would allow you to print a b&w image on color print stock, where even if you pick up a slight color tint, it won't shifting due to changes in printer lights. But the only way to get a true b&w print is to print on b&w print stock. B&W images printed onto color print stock always pick up a color cast, no matter how faint.
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#4 John Pytlak RIP

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Posted 17 February 2006 - 04:08 PM

Although you can get very acceptable monochrome images on a color print film, as David notes, there is usually a very slight "tint" in the highlights and shadows, even when the midscale is truly neutral. Typically, the highlights are a bit warm, and the shadows are a bit cool. This is because color print film is optimized for color images.

Silver image prints (e.g., KODAK B&W Print Film 2302) will give a true B&W image:

http://www.kodak.com...1.4.8.6.6&lc=en

But silver image prints are more prone to heat damage or focus flutter during projection, since they absorb much more infrared energy during projection.

http://www.kodak.com...ytlak/heat1.pdf

http://www.kodak.com...ytlak/heat2.pdf

For optimum projection life, B&W prints should be edgewaxed per SMPTE Recommended Practice RP151.
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#5 martinboege

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Posted 17 February 2006 - 04:20 PM

There is no such thing as a half-point correction.

The one argument for doing a D.I. is that at least the output will be timed and hopefully can then be printed at one light, which would allow you to print a b&w image on color print stock, where even if you pick up a slight color tint, it won't shifting due to changes in printer lights. But the only way to get a true b&w print is to print on b&w print stock. B&W images printed onto color print stock always pick up a color cast, no matter how faint.

There is no such thing as a half-point correction.

The one argument for doing a D.I. is that at least the output will be timed and hopefully can then be printed at one light, which would allow you to print a b&w image on color print stock, where even if you pick up a slight color tint, it won't shifting due to changes in printer lights. But the only way to get a true b&w print is to print on b&w print stock. B&W images printed onto color print stock always pick up a color cast, no matter how faint.


The D.I, was pure B&W, the problemis that it actually shifts from one scene to another, some may be one color and some in others, so there is no such thing as one light for all the print. I dont know if it is problem of the lab.
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#6 David Mullen ASC

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Posted 17 February 2006 - 05:02 PM

The D.I, was pure B&W, the problemis that it actually shifts from one scene to another, some may be one color and some in others, so there is no such thing as one light for all the print. I dont know if it is problem of the lab.


Then the D.I. was done incorrectly. Why should a digitally-timed monochromatic image shift in color shot by shot in the output, requiring scene-to-scene timing to remove it? It's a b&w image after all -- it doesn't have any color in it! One shot shouldn't have been output with more red and the next with more blue.

Unless it wasn't timed correctly digitally and now you're attempting to time it one more time in film.
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#7 martinboege

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Posted 21 February 2006 - 01:23 AM

First of all thanks for the replies, This is a great place to share ideas.
The point is, may be the color shift does not happen scene by scene, but from dense scenes (dark ones wich tend to some color near the cyan, and bright scenes wich tend to redish tones), not all the same. This is the problem, we know that, but the C-reality telecine in Da vinci 2k, had turned all the chroma down, balanced for B&W, there is not a chance of getting those colors to the transfer, is there?, How is that possible if all the scenes have been monitored always with the waveform monitor and vectorscope and all electronic stuff, and the chroma was always cutted away?.
The solution is in the timing I think, because we tried all ready to take out the chroma in the laser graphics machine in the data to film process, and the result was the same. So the color shift is in the lab, I think.
greetings
Martin Boege DP, Mexico City
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#8 John Pytlak RIP

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Posted 21 February 2006 - 11:10 AM

First of all thanks for the replies, This is a great place to share ideas.
The point is, may be the color shift does not happen scene by scene, but from dense scenes (dark ones wich tend to some color near the cyan, and bright scenes wich tend to redish tones), not all the same. This is the problem, we know that, but the C-reality telecine in Da vinci 2k, had turned all the chroma down, balanced for B&W, there is not a chance of getting those colors to the transfer, is there?, How is that possible if all the scenes have been monitored always with the waveform monitor and vectorscope and all electronic stuff, and the chroma was always cutted away?.
The solution is in the timing I think, because we tried all ready to take out the chroma in the laser graphics machine in the data to film process, and the result was the same. So the color shift is in the lab, I think.
greetings
Martin Boege DP, Mexico City


Again, the sensitometry of the color print film is optimized for making COLOR prints. If you print a silver-image B&W negative directly onto the color print film, you will be able to get a reasonably neutral print midscale, but the highlights will tend to be a bit warm, and the shadows a bit cold (depending on the lab's process). Many B&W films have been released using color prints, so the "tint" is subtle and not usually noticed by audiences. But for "true" B&W prints, you still need to use a silver image print film like Kodak Black-and-White Print Film 2302.
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#9 martinboege

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Posted 28 February 2006 - 02:44 PM

Thanks for the advice, So the 5201 LUT has no opinions?
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#10 Dominic Case

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Posted 28 February 2006 - 05:53 PM

A DI done properly is a very powerful way of correcting the image so that it WILL print with a neutral tone scale onto colour print stock. But it has to be timed/graded correctly in the digital stage: the eye is very sensitive to b/w images, and a half-point shift from scene to scene is more apparent than for a full colour sequence.

If you simply output a monochrome image holus-bolus onto film and expect it to work, it won't. As John has explained, it isn't that simple: there will always be a cross-over from highlight to shadow, so it's impossible to get a fully neutral scale from white to black. That's not the lab's fault, it just is what it is.

But if your DI is done by a facility that also processes the negative and makes the prints, then they should be able to make a negative that will print at one light and be neutral throughout. It's a matter of controlling the digital grade, and also using an appropriate LUT for the output, that works for the entire system through to the print.
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