[pure-silver] Re: Kodak vs Ilford

  • From: "mail1" <mail1@xxxxxxxxxxxxxxxxx>
  • To: <pure-silver@xxxxxxxxxxxxx>
  • Date: Fri, 21 Mar 2008 22:26:49 -0700

Richard, Your comments on film curves verses film types is excellent.

My thought on Seascapes with foaming waves and clouds is that aerial haze
and moisture reduces brightness and gradation in clouds and distant land
masses. The foaming waves in the foreground retain brightness due to the
reflection off the water, and foam. This creates interesting problems. The
Subject brightness ratio of the wet rocks and bright foam is quite high and
usually requires some compensation in development with an increase in
exposure. Unfortunately this compensation causes the local subject
brightness range of the distant lands and clouds to be much lower. 

One of the solutions I used was to key the exposure to the dark rock to
maintain definition in the shadows. The compensation in development was
determined by the subject brightness ratio between the rocks, and surf. This
compensation contributed to reducing the local contrast in the clouds.
Fortunately I was able to reclaim the local contrast to some degree with a
combination of a polarizer filter to enhance the gradation of the clouds
combined with a medium yellow filter to reduce the haze. I had success with
Neopan 400, my film test plots a short toe, and long straight curve, which
is different than Fujifilm's published curve I used compensation staining
developer Exactol-lux at 50-1. I tried to develop the negative for a Subject
Brightness Ratio that matches a paper exposure scale of 1.10-1.15 when
exposed by my cold light. I checked the exposure scale of the negative by
measuring the shadow, and surf highlight with an on easel photometer. This
confirmed I had developed the negative correctly. The negative looks rather
dense with good gradation. This insured the foam highlights in the negative
had enough density to print a bright white with out loss of detail. The
clouds and distant costal land printed flat with soft gradation in the
clouds. I was able to correct the tonality with a grade 4 burn to darken and
increase the local contrast. I then carefully bleached back the clouds to
balance the highlights in the clouds with the surf.

Jonathan Ayers  [mail1@xxxxxxxxxxxxxxxxx]

-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Friday, March 21, 2008 6:43 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Kodak vs Ilford


----- Original Message ----- 
From: "Janet Cull" <jcull@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, March 21, 2008 5:34 AM
Subject: [pure-silver] Re: Kodak vs Ilford


> When you say, coarse and fine grain, do you mean grain 
> that in the  print will show up as much grain and/or 
> little grain?  Grainy  *looking* or smooth?  I don't want 
> to assume I know what you mean,  because I'm not always 
> sure I do.
>
> Janet
>
>
    The greatest effect on grain is the characteristic of 
the emulsion. Developers have an effect, but it is 
relatively small compared to the built-in grain of the 
emulsion. Despite much improvement in emulsion technology 
the old rule still applies: faster film is grainier than 
slower film. Tabular grain films, for various reasons, tend 
to have finer grain for a given speed than conventional 
grain films. Also, the current T-grain films, Kodak T-Max, 
Ilford Delta, and Fuji Acros, all have relatively thin 
emulsions which leads to greater resolution and sharpness 
(they are not the same). However, partly because of the 
thinner emulsions, they tend to be fussier about control in 
processing.
    The curve shape of the emulsion also is controlled by 
the way its manufactured. The developer can have a 
relatively minor effect on the curve but does not 
fundamentally change it. The exception is when a special 
purpose developer of the "compensating" type is used, or 
stagnant development is used, which tends to limit the 
development of the denser areas of the negative hence 
lowering the highlight contrast. While many feel that this 
yeilds better highlight detail it can also limit detail 
because the highlight contrast is too low for variations in 
density to be visible. The problem here is really the limit 
of density range of the usual reflection print which can not 
reproduce the full range of brightness of many subjects, or 
even get near to it. The eye tends to judge the quality of 
an image by the mid-gray values so that, unless the 
highlights are obviously completely blown out, and unless 
the shadows are completely dark where the eye expects some 
detail, the image will be acceptable where a low contrast 
image embodying a wider range of subject values will look 
flat.
    The toe, or low exposure end, of all films has a lower 
contrast than the body of the curve. Films are generally 
classified as being one of three types: long toe, medium 
toe, and short toe. Most general purpose films are medium 
toe. This is partly to insure that small exposure errors 
don't completely eliminate shadow detail. However, the 
effect of the toe is to lower contrast of the shadows. For a 
medium toe film with a fairly long straight line section 
increasing exposure to move the minimum exposure up the toe 
to a higher contrast section will often result in improved 
rendition. Short toe films have fairly high shadow contrast 
which is not much increased by increase in exposure. Short 
toes also tend to compensate for lens flare, the main effect 
of which is to decrease shadow contrast.
    There are a few very long toe films. Currently the only 
one I know of is Kodak Tri-X ISO-320 which is available as 
sheet film in 120 rolls. Note that the ISO-400 version of 
Tri-X is a medium-toe general purpose film. The ISO-320 
version has a curve which is upward deflected at all points. 
That means that the contrast increses steadily with density 
and there is virtually no straight line portion of the 
curve. This film was designed mainly for studio work where 
there is little flare. The idea was to produce images with 
bright highlights. If one compares the curves for this film 
with a short toe, long straight line film like 100T-Max or 
400T-Max you will find that if the shadow and highlight 
density points are matched, and both films are processed to 
the same contrast index, the mid-gray densities of the long 
toe film will be lower than the straight line film resulting 
in a darker rendition of these tones on the print. Such 
rendition can yield quite dramatic pictures of certain 
subjects, for instance of seascapes with foaming waves or 
skys with cloud patterns. It also can be used to exagerate 
skin textures in portraiture.
    The curve shape and grain both affect the image but are 
different things. A factor which is related to grain is the 
"smoothness" of tone reproduction. Finer grain films, and 
larger negatives, tend to produce "smoother" tone rendition. 
This is a characteristic easy to see but hard to describe. 
If what you want is smooth tone rendition the way to get it 
is to use the slowest film you can and to make the largest 
negatives you can (of course up to a limit). For size, the 
largest gain is going from 35mm to anything larger. Even 
4.5x6cm shows a definite improvement in smoothness. Once you 
are at about 6x6cm the gain is relatively little for larger 
negatives.
    To my eye there is a lack of smoothness in 35mm 
pictures. I have been able to get something like this 
quality by using 100T-Max in Perceptol or Microdol-X (they 
are identical). This combination gives negatives nearly as 
fine grain as the late, lamented, Technical Pan in Technidol 
developer, not quite but pretty close, and with considerably 
more speed and much less fussiness.
    If you _want_ grain you must use relatively fast films 
and developers which do not tend to suppress grain, Rodinal 
being a good example. However, again, grain is mostly 
built-into the film and very fine grain films will still be 
fine grain even in Rodinal.
    There is a great deal more to this and I have written 
too much already. I've also over simplified a lot but I am 
trying to make some rather confusing concepts clear. Maybe 
not the best thing to try early in the morning.
    I probably should have just asked what sort of images 
you want to accomplish.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx


============================================================================
=================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.

No virus found in this incoming message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.21.7/1335 - Release Date: 3/19/2008
9:54 AM
 

No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.21.8/1337 - Release Date: 3/20/2008
8:10 PM
 

=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

Other related posts: