DEAR RICHARD,
My 70 year old brother and I (66) joke that we have "half"zheimer's because we
often struggle to remember words so "I resemble that remark"! LOL!!!. But I
know how detail oriented you are and I hoped you would appreciate the info. I
curated a collection of 2400 glass plate negs made here in Barbados between
1880 and 1937 and saw some hellacious examples of hallation on them.
CHEERS!
BOB
From: "`Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, March 17, 2017 2:42:58 PM
Subject: [pure-silver] Re: Update On 1975 Kodak Film Pack
Bob, you must realize I have reached the age where words sometimes escape me. I
remember them eventually but since I write pretty much free-hand I must
sometimes paraphrase, as in this case. Of course, the effect I was describing
is halation. In the days of glass plates it could be very serious but self
masking printing methods like printing out paper can, to some degree, mitigate
them by allowing what amounts to burning in the highlights. It was common
practice with glass plates to coat the back with a sort of caramel. This was
dark brown and helped absorb some of the light reflected from the back of the
plate. It soaked off in processing. I remember their being instructions for
coating the unexposed plates in some very old books. Halation is still a
problem with flexible film but less so, partly because the index of refraction
is closer to that of air but mostly because its thinner.
Perhaps my use of the term "flare" was not a good choice because the effect of
halation in old photos is often blamed on lens flare. They may sometimes look
similar but are from very different causes. The pictures of the insides of
factories, for instance, where the area around windows is blocked is mostly
from halation rather than flare, although flare can cause some of it.
On 3/17/2017 3:40 AM, bobkiss caribsurf.com wrote:
DEAR RICHARD,
FYI, the tech term for flare within film, especially that resulting from image
making light passing out of the back of the film base is "halation". And the
layer of gelatin with soluble dye on the back of the film was called the
antihalation layer and dye. You can see in many old photos and movies large
balls of fuzzy light around highlights or any light sources in the shot. That
halation was pretty hellacious! LOL!!!
CHEERS!
BOB
From: "`Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, March 17, 2017 2:20:36 AM
Subject: [pure-silver] Re: Update On 1975 Kodak Film Pack
Fast film has more fog even when new and gets foggier with age than slow film.
When the specs say base plus fog the base is the density of the support and any
anti-light piping or residual anti-flare. This usually does not change with
age. Anti-light piping is a pigment in the support itself and is found mostly
in 35mm negative still film. I am not sure it is used on motion picture stock.
It is not found on reversal films and I don't think its used for color negative
films. The anti-flare coating is usually a dye in the back coating. Back
coating is a layer of gelatin on the back of the film to reduce curling. The
dye is usually removed by the sulfite in both the developer and the fixing
bath. Color films and some B&W films have a layer of dye under the emulsion,
between it and the support, which also prevents reflection from the base to
reduce or eliminate flare. This is also usually removed or decolorized during
processing. One problem with the decomposition of "safety base" films is that
the reaction products of the degradation of the support can cause the dyes used
for anti-flare to become colored again, often in blotchy patterns.
Another cause of extra density is residual sensitizing dye. This is found
mostly in tabular grain films like T-Max and results in a slight pinkish
overall stain. The dye can be bound up in a way similar to thiosulfate and
fixer reaction products. While Kodak has stated that its a sign of insufficient
fixing it can remain even after extended fixing with ammonium thiosulfate fixer
and the use of two bath fixers. Sulfite wash aids will get rid of it very
quickly.
If the fog or base density is uniform it can be compensated for by somewhat
longer printing exposures but has no other effect. It does not change the H&D
curve of the film, at least if not too severe. The use of an anti-fogging
agent, like potassium bromide, can reduce fog, especially on old film, but also
changes the film curve, essentially moving the exposure up the toe toward the
straight line portion and reducing film speed.
Remember that the ISO standard for B&W negative still film gives about the
minimum exposure possible with good shadow detail. The standard requires some
ageing of the film so that its relevant to film when it reaches the market. The
method used to determine speed of reversal films, both B&W and color, for color
films of all types, and for motion picture films of all types is not the same
and states something closer to the optimum speed rather than the maximum.
Something like this can be found for B&W negative still film by increasing
exposure by about one stop over the box speed. This can be beneficial for tone
rendition and does no harm otherwise other than resulting in somewhat denser
negatives. However, it should not affect over all contrast index although the
increase in toe contrast may result in a somewhat contrastier appearance of the
same scenes.
The major film manufacturers put a good deal of research into making the
emulsions stable with time. For one thing film is a perishable so the longer
the shelf life the lower the cost of keeping supplies fresh.
On 3/16/2017 9:02 PM, Richard Lahrson wrote:
BQ_BEGIN
Hi,
I just developed two rolls of outdated Ilford 3200 and
a quick read on the densitomer says 0.6 for filmbase
plus fog, so that's thick, but I exposed at 800 and
over developed some. I can print through the fog.
Faster films seem to have more filmbase.
Rich
On Thu, Mar 16, 2017 at 7:10 PM, Mike Kirwan < mkirwan@xxxxxxxxxxx > wrote:
BQ_BEGIN
150 Do-it-yourself Black and White Popular Photographic Formulas
Purchased it in the early 1980’s along with a chemical balance from a local
Photo store that was changing hands…
Mike
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto: ;
pure-silver-bounce@xxxxxxxxxxxxx ] On Behalf Of kgriffit
Sent: Thursday, March 16, 2017 6:59 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Update On 1975 Kodak Film Pack
Which Dignans book do you have?
Sent from my U.S. Cellular® Smartphone
-------- Original message --------
From: Mike Kirwan < mkirwan@xxxxxxxxxxx >
Date: 03/08/2017 19:05 (GMT-08:00)
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Update On 1975 Kodak Film Pack
I am always amazed how well really old film can turn out. I developed a couple
of rolls of Efke R14 that I had purchased in the 1980's. I shot at 40 ASA and
developed in Modified Divided D76 (Dignan's book) for 4 minutes in baths A & B
and wow, wow, no fog, crisp images full of detail. I have about 20 rolls left,
so I think it time to put them to good use before I expire.
Now to try a few sheets 4x5 GAF SUPERPAN which expired in 1981. Actually it
states Military Expiration Date January 1981. The box states an ASA of 250
determined by ANSI PH2.5. Probably will start at 200 ASA with the same times.
The modified D76 calls for a small amount of bromide which probably helps with
keeping fog to a low level.
Once I have tested the GAF, will try a few sheets of Kodak Super Pamchro-Press,
Type B that expired in August 1954 - ha! almost as old as me. Kodak suggests
developing in DK60a, D-19 or DK-50, and states the film is a fast Type B
panchro of moderately fine grain suitable for portraiture and other commercial
work. My old Kodak handbook suggests an ASA of 250 and develop between 6-8
minutes in the recommended developers. Not holding out any hope for this film
Mike
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx [
mailto:pure-silver-bounce@xxxxxxxxxxxxx ] On Behalf Of Tim Daneliuk ;
Sent: Wednesday, March 08, 2017 5:24 PM
To: Pure-Silver Mailing List
Subject: [pure-silver] Update On 1975 Kodak Film Pack
Recall that I scored a new old stock Kodak Tri-X 2 1/4 x 3 1/4 film pack a
couple of months ago. Expiry was Nov. 1975
Tonight I took a few shots with in in my Baby Speed Graphic and 103mm Ektar and
then "robbed" them from the pack.
I normally expose TXP (when I had it) at ASA 160 and develop for 7 min in DK-50
1:1 (I happened to have that mixed up and
ready to go). In this case, in deference to the film's age,
I shot at ASA 125 and developed for 8 min.
I almost fell over - there is no visible fogging. The unexposed edges - to the
eye at least - look like normal Tri-X. Contrast could be higher (a bit more
development time) and exposure could be just a tad deeper. Still, 40+ year old
film that produces perfectly normal negs is just a little bit shocking.
I think the remainder of the pack is likely to get exposed at ASA 100 and
developed for 10 min.
Happy to answer any further questions...
P.S. DK-50 has the reputation of reduced film fogging. It sure seemed to
work here.
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BQ_END
--
Richard Knoppow dickburk@xxxxxxxxxxxxx WB6KBL
BQ_END
--
Richard Knoppow dickburk@xxxxxxxxxxxxx WB6KBL
