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Density range/latitude of Kodak Eastman Double-X


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#1 Stephen Perera

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Posted 02 October 2017 - 04:10 AM

OK I know I know...run your own tests etc but would love to hear what the results of YOUR tests have been with this stock in terms of latitude....

 

.....in practice how many stops over and under my key exposure I can get away with in a high contrast scene for example....

 

Im more concerned with blown highlights than anything as will be shooting contrasty scene exteriors in full Mediterranean sun at all hours of the day......obv if I will try and balance the fill to background using reflectors and some lights but you know....its hard to fill in full backlight sun from more than 5 meters


Edited by Stephen Perera, 02 October 2017 - 04:12 AM.

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#2 Simon Wyss

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Posted 03 October 2017 - 02:10 AM

Fast black and white films have a mixture of grain forms and grain sizes, chemically correct salt crystals. Silver salts. There are also different silver salts, namely bromide and a little iodide. In some cases nitrates, too.

 

The crystals are partially veiled inside, meaning that there is already some genuine silver in them. The future developed silver will deposit on those germs. In strongly exposed areas all salts are affected and decompose. In weakly exposed areas only the highest sensitive salts get affected. From these chemical differences we find the film reacting not in exact lineal fashion but rather as sort of an S curve when plotted. The curve’s toe and shoulder show that the differentiation of shadows and higher lights is limited by the physical and chemical facts about those crystals.

 

A negative’s information will be put onto another film stock, again a non perfect emulsion with limited differentiation at the extremes, but the positive emulsions work harsher, with stronger contrast, and develop a higher maximum density. According to the Goldberg condition a neutral or perfect image contrast is the product of negative and positive contrast. These are laboratory issues whose task it is to produce projection prints that display a nice image. Lab technicians need to know an average Albedo of cinema screens and an average brightness level, else it is impossible for them to determine the contrast and the mean density of prints. In other words, calculating backwards from a theoretically perfect image on a white screen of 100 percent gain the prints’ contrast and density are defined. The Callier effect comes also into play with the projection lens and illuminating system, pushing print contrast to a Gamma of about 1.55.

 

Small gauge film projection happens often with lesser screens or in not completely dark surroundings, thus an 80 percent gain is generally assumed. Lighter but a little more contrasty prints are needed. Portable projectors’ optics are also different from commercial cinema’s arc lamps.

 

In order to judge on your work, you want contact positives off your negatives, presented under about the same conditions as are expected with the majority of theatres. Do you see how complicated matters are?

 

You cannot discuss photographic qualities by the image on a viewer screen. Your questions aim at the heart of cinema and that has to do with what I’m describing. As a cinematographer you should know that film processing, development of exposed photographic materials, is embedded in a long chain of conditions. Finally, the lighting on set actually is dictated by all the aforementioned factors. Always think of them. Always look on the bright side of life.


Edited by Simon Wyss, 03 October 2017 - 02:14 AM.

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#3 Dirk DeJonghe

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Posted 03 October 2017 - 02:25 AM

If you want a simpler explanation, read Appendix 1 'Film Testing Procedures' in Ansel Adams' 'The Negative'.

He will show you how to do an empirical test to find the practical speed of your emulsion with your exposure meter, your lens and camera setup, and the labs processing.

Once you have determined the correct film speed (you only need about 5 meters to do this test), then you do the classic keylight test where you start from the speed found in the previous test and search for the limits of over and underexposure. From the previous test you already know that the limit of the shadow detail is at -4 stops by design, you only have to find the limits of overexposure. 

You have control over the shadows with your exposure and 'let the highlights fall' according the the latitude of the filmstock you tested in the keylight test.


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#4 Stephen Perera

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Posted 03 October 2017 - 03:05 AM

thanks for the tips and info...I've got all three Adam's books The Camera - The Negative - The Print - for about 25 years now will re-read!


Edited by Stephen Perera, 03 October 2017 - 03:06 AM.

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#5 Stephen Perera

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Posted 03 October 2017 - 03:31 AM

regardless of me doing my own testing what in general have you all found with it?


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#6 Michael Carter

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Posted 17 September 2018 - 06:56 PM

I'm still working on it
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#7 Michael Carter

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Posted 24 September 2018 - 02:54 PM

Done. https://m.youtube.co...h?v=PskMmBzYpIU
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#8 Michael Carter

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Posted 24 September 2018 - 06:00 PM

Oops, n74
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#9 Michael Carter

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Posted 29 September 2018 - 03:07 PM

7222 f16 in 3200 foot candles 24 fps H16Rx4 no filters dev in RO9 1:300 3 1/2 hours

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#10 Michael Carter

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Posted 29 September 2018 - 05:18 PM

Why is the film so pink?
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#11 Michael Carter

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Posted 29 September 2018 - 06:13 PM

Bleaching the film a min. before developing (and clearing) got rid of the pink. That is how to use Fomapan R-100 as negative and I tried it with N74 and 7222. They react all the same. Film turns white then develops black.
Another observation. RO9 developer turns black after developing 7222 (without any bleaching) but not so N74.
What is going on here?
Some say doubling fixer time gets rid of the pink.
Pre-bleaching worked better.

Edited by Michael Carter, 29 September 2018 - 06:15 PM.

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#12 David Mullen ASC

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Posted 29 September 2018 - 11:14 PM

Why does it matter if the b&w negative has a color cast? It's either going to be printed on b&w stock anyway or scanned and reversed electronically into a positive and turned monochrome.  I suppose if you plan on printing it directly to color print stock but want a neutral grey image, you'll have some work cut out for you.


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#13 John Salim

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Posted 30 September 2018 - 07:11 AM

Pretty much every B&W negative film ( except print films ) have some sort of cast.

 

John S


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#14 Michael Carter

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Posted 30 September 2018 - 09:17 AM

Washing more removes most. The video camera used to make the stills added color.
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#15 Michael Carter

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Posted 30 September 2018 - 01:12 PM

The film was washed again longer using filtered water then photographed again this time with papers next to the sides of the film and auto color corrected. Now it looks about as it does to the eye. Pink is gone. Now it is slightly purple and mostly gray, but light gray.
Exposure was in the center part of the bracket series, about 25 Asa, film is 7222, no filters were used in brightest sunlight.

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#16 Stephen Perera

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Posted 30 September 2018 - 01:19 PM

reminds me of the Kodak TMax photographic negatives......its the familiar pink/purple stain on the negative.......nothing new to what Im seeing with yours......Fuji's magnificent Neon Acros 100 washes and dried clear....Ifford's superb Deltas are clear too.....


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