Jump to content


Photo

Density range/latitude of Kodak Eastman Double-X


  • Please log in to reply
4 replies to this topic

#1 Stephen Perera

Stephen Perera
  • Basic Members
  • PipPipPip
  • 167 posts
  • Other
  • Gibraltar, Europe

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.

  • 0


#2 Simon Wyss

Simon Wyss
  • Basic Members
  • PipPipPipPip
  • 1353 posts
  • Other
  • Basel, Switzerland

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.

  • 1

#3 Dirk DeJonghe

Dirk DeJonghe
  • Basic Members
  • PipPipPipPip
  • 603 posts
  • Industry Rep
  • Kortrijk,Belgium

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.


  • 1

#4 Stephen Perera

Stephen Perera
  • Basic Members
  • PipPipPip
  • 167 posts
  • Other
  • Gibraltar, Europe

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.

  • 0

#5 Stephen Perera

Stephen Perera
  • Basic Members
  • PipPipPip
  • 167 posts
  • Other
  • Gibraltar, Europe

Posted 03 October 2017 - 03:31 AM

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


  • 0


Media Blackout - Custom Cables and AKS

Technodolly

CineLab

Glidecam

Aerial Filmworks

FJS International, LLC

CineTape

Metropolis Post

Abel Cine

rebotnix Technologies

Rig Wheels Passport

Ritter Battery

Broadcast Solutions Inc

The Slider

Visual Products

Willys Widgets

Wooden Camera

Tai Audio

Gamma Ray Digital Inc

Paralinx LLC

Gamma Ray Digital Inc

Ritter Battery

CineTape

Technodolly

FJS International, LLC

Media Blackout - Custom Cables and AKS

Visual Products

Broadcast Solutions Inc

Paralinx LLC

Abel Cine

Glidecam

Wooden Camera

Willys Widgets

Aerial Filmworks

The Slider

Metropolis Post

Rig Wheels Passport

Tai Audio

CineLab

rebotnix Technologies