Zone System_ Film Density
Transcript of Zone System_ Film Density
-
8/8/2019 Zone System_ Film Density
1/3
About Us Book lists Current Newsletter Gallery Guestbook/mini-gallery
Zone SystemTable of Contents
CopyrightQuicktour 1 2 3
Intro 1 2tables
Chapters 01 02 03 04 05 06 07 08 09
Chapter 5 index a b c d e f g h
browser windowemulator 1 2 3filmtestsfaq
searchzs books
Zone SystemChapter 5 Film Development and Density
Film density
prev next
What is film density?
Black and white negatives usually have some dark areas and some clearer areas. Film Density is a measure of thedarkness or opacity of the film at a given area of the negative.
There is a correlation between the range of film density on a negative and the way the negative prints on a paper ofany given contrast. There are other complicating factors too. Let's start with something you can measure with a
light meter. If you take a sheet of photographic paper, expose half of the paper to a strong light white light but keep
the other half unexposed, then develop the paper fully, you will have a piece of paper that is half black and half
white. If you measure the one side then measure the other side using a light meter, you will find that the paper
reflects roughly 5 F-stops more light from the white side than the dark side. Common sense will allow you to see
that no matter how great the range of light in the original subject you choose to photograph, the reproduction is
going to be limited to the range of light between the light side and the dark side of the paper you print on. These
two print values are known as Dmax and Paper base White or occasionally Dmin.
Introducing The Abominable Snowman to the picture
Suppose you have a negative that prints perfectly on a certain paper. Imagine that the original subject had no pure
white areas in it -- just a range of grays from very dark to pretty light. Let's also say that you developed the film for
9 minutes in your favorite developer. When you print the negative, everything just works out perfectly. You have
nice rich shadow values and nice open detailed highlights. The film and your paper are working together perfectly.
Okay, now suppose that at the moment of exposure the abominable snowman, dressed in a white tux, suddenly
jumped into the middle of a shaft of light in the middle of your picture. Now you have a valuable image in your
camera. Wow, the abominable snowman, you'll be famous! If you take the film back to your lab and develop it for
the same 9 minutes that was working for the picture before, you will get a negative that prints great, just like
before -- except in the area of the abominable snowman. The darn thing, under similar printing conditions you were
previously using, is going to be just a big award-losing white blob in the print. The reason is that Abby reflected abunch more light than the rest of the image and therefore made a big dense blob on your negative that is going to bedifficult to print.
We have faith in you. You'll find a way to print the negative and achieve the rewards of capturing Abby on film.For now, just imagine that printing the film will be more difficult because you now have some areas that are too
dense for your normal printing techniques.
The thing that is really happening is that the range of film densities is too great for your normal paper to handle
effortlessly. A typical grade 2 paper (Normal contrast) likes to print a negative that has a density range of about 1.5
between very dark areas and very light areas. If your negatives have that sort of density range, they'll print readily
on papers of normal contrast.
The table below gives a bit more detail and descriptions about 11 points along the gray scale. These points are
given the names Zone 0, Zone 1,Zone 2, Zone 3, Zone 4, Zone 5, Zone 6, Zone 7, Zone 8, Zone 9 and Zone 10.
Their definitions are basically the information in the chart below ( also found elsewhere on this server). Some
-
8/8/2019 Zone System_ Film Density
2/3
thinkers divide the gray scale differently using more than 11 key points, or less than 11, or 11 but different ones.These are the key points as described by Ansel Adams in his bookThe Negative. The film densities represented
here are from independent testing done by one of my students under my supervision.
This particular way of dividing the gray scale into 11 named areas turns out to be exceptionally photographically
convenient. In addition to using this web site, you should get a copy ofThe Negative by Ansel Adams and read itcarefully. Then reread it. That is the book for anyone seriously interested in the Zone System. Before using any
other volume for reference material I suggest that you look at the photographs actually created by the authors and
compare them to Adams' photographs. Then if you still are tempted away from Adams's book, make 100% positivethat any other reference includes good writing about film testing, plus-and-minus development, pre-exposure of
film and more. Stick with Adams, you'll be better off in the end. Don't worry if the going is slow; it's worth it.
Table 5.1: Zone System Chart
Description, Textural Properties, Film Densities
ZoneZone
0
Zone
I
Zone
II
Zone
III
Zone
IV
Zone
V
Zone
VI
Zone
VII
Zone
VIII
Zone
IX
Zone
X
Descr.
ofprint
value
Dmax.
pureblack.
1st
perceptibl
e valuelighter
than
black.
very verydark gray
fully
textured dark
Gray
dark
middlegray
middle
gray 18%reflectance
light
middlegray
fully
texturedlight
Gray
very verylight gray
1st
perceptible
graydarker
than white
Dmin.
paperbase
white
Textur
e
none none suggestionof texture
fulltexture
fulltexture
fulltexture
fulltexture
fulltexture
suggestion
of texture
none none
Film
Density
.02 .11 .21 .34 .48 .62 .76 .97 1.18 1.33 1.44
Notes:
The figures above came from a series of tests performed by Martha Milsaps during the summer of 1991
(I think :-). Martha tested 35mm Kodak T-Max 100 film for printing on a condenser enlarger; I oversawthe test procedures and results. These figures may differ from your own; they represent appropriate film
densities for the particular equipment Martha was using in the darkroom. If you are using a different
film or are using a different enlarger, then you figures *should* be different from these. So do not worry
if your test results vary somewhat from these. Even so, these densities are an excellent representative set
that you can use as known good values to compare to your own film test results.
Next: Practical Implications of Film Density
prev next
-
8/8/2019 Zone System_ Film Density
3/3
Solar Energy
Charity
Helping RelievePoverty ThoughThe Provision of
Solar Energy.Join Us!
Public Service Ads byGoogle
Prisoners
$24.95 More Info Buy Now
by Arne Svenson
Usually ships in 24 hours
(As of 10/6/2004, 1:01:53 AM EST)
NCPA
1998 Gallery
Browse the Photography
Resource
Homepage Go
http://www.cicada.com/pub/photo/zs/chapter5/a.html
Site by Cicada Consulting Group (888 424-2232) Copyright LewisDowney 2001 All rights reserved. Pagemodified: Wed,Apr 18,2001