Fuji Velvia Reciprocity Chart
Courtesy of Michael K. Davis
Related Local Links:
Download Michael K. Davis' Velvia Spreadsheet
(Excel 5+)
120/220 Film Page (includes reciprocity data)
Related Links:
[See Ilford and other film mfgers pages listed in 120/220 Film Page
links
June 1998 NYIP Reciprocity Failure Article
Ilford Site (includes reciprocity data on films)
Kodak Reciprocity Data site (PDF)
Date: Sat, 30 May 1998
From: Robert Monaghan [email protected]
To: [email protected]
Cc: Robert Monaghan [email protected]
Subject: reciprocity failure - Re: Film Speed Testing
Greetings y'all ;-)
One area in which film testing seems to be useful is reciprocity failure
and color shifts with longer exposures (as in night-time photography).
Even at relatively short one second exposures, you will probably be up to
a stop off due to reciprocity failure alone, as the guides below show...
I would be interested in locating info on reciprocity characteristics of
specific med fmt (or even 35mm emulsions) films - esp. Fuji and non-kodak
films which don't seem to have this data published anywhere. Color shifts
and recommended filtrations would also be highly useful too. I would also
be interested in film speed testing suggestions, but esp. any tricks
aimed at reciprocity estimation and calibration.
I have archived a few related posts on my Moonlighted Landscapes Exposure
Guide page at http://www.smu.edu/~rmonagha/mf/moonlight.html - but except
for some Kodak films listed in the Kodak prof photo guide, there doesn't
seem to be a lot of info out there on the WWW - the most useful guide is
http://www.users.dircon.co.uk/~migol/photo/data.html#d1
which suggested:
Colour Neg:
1 sec: + 1 stop
10 secs: + 2 stops
100 secs: + 2.5 stops
Colour Transparency:
1 sec: + 0.5 stop
10 secs: + 1.5 stops
100 secs: + 2.5 stops
B/W:
1 sec: expose for 2 secs, underdevelop by 10%
10 secs: expose for 1 min, underdevelop by 20%
100 secs: expose for 20 mins, underdevelop by 30%
obviously, change aperture rather than time unless you want to correct
your corrections ;-)
There is also an issue of film color shifts over time interacting with
this exposure reciprocity fix - e.g., velvia reportedly shifts towards green
but if you add a filter to compensate, then your filter factors have to
be corrected as well in really long exposures ;-) Other films have little
color shift (ektar 25?) up to a relatively long time exposure period.
Again, it would be nice to have a source of color shift information - any
leads?
so film speed testing shouldn't be looked at a single value issue - film
speeds will range greatly depending on the exposure time due to
reciprocity failure, and the effect is already noticeable at one second
exposures.
fyi - regards bobm
* Robert Monaghan POB752182 Dallas Tx 75275-2182 [email protected] *
Postscript:
From Roger Hicks' Medium Format Handbook, p.127:
1 second - +1/3rd to 1/2 stops
10 seconds - +1 to 2 stops
100 seconds- +3 to 4 stops
n.b. Daylight Color Slide Film
| Typical Exposures and Filters for Reciprocity Failure | |||
|---|---|---|---|
| Film | 1 second | 10 sec. | 100 sec |
| Kodacolor II | +1/2 stop, none | 1 1/2, CC10C | 2 1/2, CC10C+10G |
| Kodacolor 400 | +1/2 stop, none | 1, none | 2, none |
| Ektachrome 64 | +1 stop, CC15B | 1 1/2, CC20B | not recommended |
| Ektachrome 50 | none, none | 1, CC20B | not recommended |
| Ektachrome 200 | +1/2 stop, CC10R | not recommended | not recommended |
| Ektachrome 400 | +1 stop, none | 1 1/2, CC10C | +2 1/2, CC10C |
| Ektachrome 160 | +1/2 stop, CC10R | 1, CC15R | not recommended |
| Kodachrome 64 | +1 stop, CC1OR | not recommended | not recommended |
| Kodachrome 25 | +1 stop, CC10M | 1 1/2, CC10M | 2 1/2, CC10M |
| Fujicolor F-II 400 | +1 stop, none | 2, none | 3, none |
| Fujichrome R-100 | +1/3 stop, CC05C | 2/3, CC10C | 2, CC20C |
| Agfachrome 64 | +1/2 stop, CC05B | 1, CC10B | 3, CC15B |
| Agfachrome 100 | +1/2 stop, CC05B | 1, CC10B | 3, CC15B |
| Photomicrography 2483 | +1/2 stop, CC10Y | 1 1/2, CC10Y | 3 1/2, CC10Y |
| Pan B+W films | +1 stop, 10% less development | 2,
20% less development | 3, 30% less development |
Comments: The above table illustrates how variable films can be in their reciprocity effects. Some films such as Fujicolor II require no filtering. Other films require the same filtering from 1 to 100 seconds (#2483). Still other films develop multiple color shifts in longer exposures (Kodacolor II). The latest reciprocity data is available directly from the manufacturer's websites - see links at Films.
Battery packs are available that can be carried in jacket or coat and used with wire connections to provide power to camera.
Medium
Format Digest Posting:
From: barry eastlack [email protected]
Subject: Response to Best Films for Night Photography?
Date: 1997-11-24
Again, Velvia is an excellent choice, as I have shot both downtown Dallas and the Morton Meyerson. Reciprocity ratings for Velvia as follows:
Meter Reading: Exposure time: 8 seconds 12 seconds 10 16 12 19 16 28 20 39 25 49 32 66 40 88 50 116 64 158
Medium Format Digest Posting:
From: Zonghou Xiong [email protected]>
Subject: Response to Best Films for Night Photography?
Date: 1997-11-25
Be warned that Velvia will turn some underexposed night objects including clouds to green. Bright light spots vs. dark building will be fine, though. You might have to use a red filter and extend the exposure by one stop.
[Ed. Note: I thought the above 120 film data for night photography might stimulate some readers to try out some fun night photography activities!]
From: Helmut FAUGEL [email protected]
Newsgroups: rec.photo.film+labs
Subject: Re: Reciprocity
Date: Mon, 22 Jun 1998
W E LEIBOW schrieb: > > Does anyone have reciprocity tables for Fuji Astia, Kodok E100 s
For which times?
IMHO E100S(W) does not need any correction up to 2 minutes.
Astia needs about +1/2 stop at 30s to 1 min, +1 stop at 2 min and
about +1 1/2 stop at 4 min.
--
Helmut Faugel
From: bergstro [email protected]
Newsgroups: rec.photo.film+labs
Subject: Re: Reciprocity
Date: 22 Jun 1998
Hi Bill,
I've been using the same table for E100S as I use for Velvia, and the
results have been reasonably acceptable (side-by-side tests with Velvia up
to about 30 metered seconds). Now that I've used a couple of boxes, I'll
be using somewhat less correction than with Velvia.
I believe the Velvia correction table I've been using is from Steve
Simmon's "Using the View Camera".
Pete
From: "Michael K. Davis" [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Velvia Reciprocity chart
Date: 27 Jun 1998
Anybody want a plotted curve for Velvia Reciprocity Correction?
Robert Monaghan [email protected] wrote:
: Greetings,
: see http://www.smu.edu/~rmonagha/mf/reciprocity.html
I had a look at the times recorded by Barry Eastlack and just had to plot
the curve. His data is a fairly good fit to a logarithmic trendline I
charted along with the data series. So... here lies another spreadsheet.
The trendline allows you to easily determine the increase in exposure time
needed for indicated exposure times from 0 to 90 seconds.
It is a uuencoded, pkzipped, MS-Excel 5.0+ file. Feel free to e-mail me
to request it as a MIME attachment, if you prefer.
[Editor's note: the file is un-uuencoded, unzipped, and linked as a
Downloadable Excel 5.0+ spreadsheet here!
rec.photo.equipment.35mm
From: "David W. Swager" [email protected]
[1] Re: Recipricity failure
Date: Wed Jul 22 06:59:35 CDT 1998
Your understanding is correct. Reciprocity failure is simply stating that
as exposure time lengthens the normal rules break down. Dealing with the
reciprocity between film speed, exposure duration and aperture, the law of
reciprocity states that to maintain constant exposure, when you change one,
an opposite change of equivalent degree must be made somewhere else. Hence
if you make a 1 stop change in aperture, then you need to provide a 1 stop
change in the opposite direction somewhere else. Typically as film speed
and aperture are set, what you end up doing is lengthening the exposure
still further which compounds the problem.
Most modern film emulsions are much better than just a few years ago. 1
second used to be a standard cut point at which reciprocity failure occured.
Most current emusions are now listed as 10 seconds. You really need to test
each film yourself, if you plan exposures of these durations. For the most
part, color shifts are more of a problem than reciprocity failure until you
get to exposure durations greater than about 4 seconds.
Red Rover wrote
> I happened across this term while reading an old intro book to >photography. The passage was short and vague, but it concerns me nontheless. >To my understanding, the term refers to fact that exposure taken at longer >than 1 second or so do not follow the same time rules then faster exposures, >that proper exposure takes a lot longer then a meter would suggest. Can >anyone elaborate on that for me. I'm considering experimenting with long >exposures, and would apreciate any info in this area. Thanks. >
rec.photo.equipment.35mm
From: [email protected] ([email protected])
[1] Re: Recipricity failure
Date: Wed Jul 22 09:00:31 CDT 1998
"Red Rover" [email protected] said,
>To my understanding, the term refers to fact that exposure taken at longer >than 1 second or so do not follow the same time rules then faster exposures, >that proper exposure takes a lot longer then a meter would suggest.
Not exactly, altho you are on the right track. I'm afraid I've been out
of school to explain it to you in technical terms, but essentially, the
different emulsions in the film begin to react differently when exposed
for longer than several 1/100's of a second. There are color and contrast
shifts that are not controllable. When taking long exposures, it's best
to bracket widely and do tons of experimentation. Don't expect to
discover any rules and don't believe your meter, as it's going to only
give you averages. But that's part of the fun. Just experiment and enjoy.
Dave
From: [email protected]
Newsgroups: rec.photo.misc
Subject: reciprocity failure - flash
Date: Fri, 31 Jul 1998
Understand reciprocity failure sets in e.g. at 1/1000th second shutter
speed or slightly higher. A flash units will fire at e.g 1/5,000th or
1/10,000th of a second and I have never seen any mention about reciprocity
failure in magazines or any text books when using flash. Can I assume
flashes are already calibrated for this for on camera flash. What about
strobelights and incident meters. Do I need to adjust aperture?
Having said that I have found that Velvia seems to be more accurate at 25 iso
setting when using on camera flash. Elite seems to need 1/2 - 2/3 stop
overexposure when using on camera as well as strobe lights.
I am using Nikon F801 (N8008) and F90 with SB25 and Bowens strobelights.
Any comments?
John Iversen
[email protected]
From: [email protected] (Mr 645)
Newsgroups: rec.photo.misc
Subject: Re: Tungsten film & reciprocity failure
Date: 1 Aug 1998
sounds more like the film was underexposed (although i missed the
original post). i have seen this very often in the agfa line. it can
tolerate some underexposure but the first color layer to suffer from
this underexposure, is the magenta layer. therefore the greenish tint
to your negs. this would also explain the speckly look to the prints.
and although the lab could correct out some of the greeenish tint, the
speckly look is not something the lab will be able to correct.
I am not sure about the Fuji Film, 2 minutes is longer than I have tried.
Unfortunatly Fuji tech help is not so easy to come by, perhaps your local
dealer will have info for you. Kodak has an 800 number, 1-800-242-2424
ext.19 and the guy at the other end will quickly answer any techincal
questions on Kodak films. I know that Kodak 64T goes to 30 seconds with
no correction, but I don't recall 2 minutes.
Jon
http://www.interpoint.net/~mr645
From: [email protected]
Newsgroups: rec.photo.misc
Subject: Re: reciprocity failure - flash
Date: Sun, 02 Aug 1998
I believe you are correct about reciprocity with elec. flash. I also believe
that at close distances and wide open, the camera/flash metering electronics
may not be fast enough to properly TTL. Finally, I believe electronic flash,
at a given zoom setting, controls exposure by the length of the flash and not
by the brightness of the light. Therefore, I would suggest stopping the lens
down and/or using a diffuser over the flash (or setting zoom flash to wider
focal length).
[email protected] wrote:
> Understand reciprocity failure sets in e.g. at 1/1000th second shutter speed > or slightly higher. A flash units will fire at e.g 1/5,000th or 1/10,000th of > a second and I have never seen any mention about reciprocity failure in > magazines or any text books when using flash. Can I assume flashes are > already calibrated for this for on camera flash. What about strobelights and > incident meters. Do I need to adjust aperture? > > Having said that I have found that Velvia seems to be more accurate at 25 iso > setting when using on camera flash. Elite seems to need 1/2 - 2/3 stop > overexposure when using on camera as well as strobe lights. > > I am using Nikon F801 (N8008) and F90 with SB25 and Bowens strobelights. > Any comments? > > John Iversen > [email protected]
Date: Mon, 3 Aug 1998
From: "Michael A. Covington" [email protected]
Subject: Reciprocity failure
Responding to a couple of questions...
Yes, there is recip. failure at extremely short exposure times (< 1/1000
sec.) as well as at extremely long ones (> 1 sec.). Or, to be more precise,
there is reciprocity failure at extremely high light levels (requiring less
than 1/1000 sec. to take a picture) and at extremely low light levels. The
film, of course, doesn't know how long the shutter is going to be open, but
it does know the intensity of the light reaching it... and it's more
efficient at some intensities than at others.
Low-intensity reciprocity failure (LIRF), the kind that shows up in long
exposures, tends to produce reduced speed and increased contrast.
High-intensity (short-exposure) recip. failure (HIRF) produces reduced speed
and reduced contrast.
I would be wary of meters that try to calculate this for you -- it varies a
lot from film to film. For example, in a 5-minute exposure, Ektachrome E200
is a good bit faster than Tri-X Pan.
Michael Covington
Author, Astrophotography for the Amateur
http://www.mindspring.com/~covington/astro
[Editor's Note: My understanding is that reciprocity effects on the short
end become important at flash durations less than 1/10,000th of a
second...]
From Nikon Digest:
Date: Tue, 4 Aug 1998
From: RIBNITZ Robert [email protected]
Subject: re:reciprocity effects
HGi there,
I think what you call low intewnsity reciprocity effect starts at
1/10.000, not 1/1.000. I have nwver had problem using 1/1.000,2000 or
higher speeds with my F801, F90, or FM2.
What you say correctly is that at low speeds (long exposures),
compensation is necessary. this is usually done by lengthening exposure
by about a third (so instead of 12s you'd do 16s), if I am remembering
corectly
Sorry to be so picky
Robert
From Nikon Digest
Date: Wed, 5 Aug 1998
From: "Bernard Languillier" [email protected]
Subject: reciprocity effects
Hi there,
This is not Nikon related but... About the reciprocity effects. As far as I
know, no general comment can be made about the speed from which reciprocity
effect occurs, it is film dependant.
however, a quick look at the Kodak page,
http://www.kodak.com/cgi-bin/webCatalog.pl?section=&cc=US&lc=en&product=KODA
K+PROFESSIONAL+EKTACHROME+Film+E200
advertising the new KODAK PROFESSIONAL EKTACHROME Film E200, will confirm
that indeed, for that top of the range film, reciprocity effect only starts
to appear for speeds faster than 1/10.000 s. However, as they do not mention
such a figure for most of their pro films on their page, I assume that the
other ones don't perform as well...
As far as low speed are concerned, for the same slide film, Kodak says that
no correction is needed up to 10 seconds, which is absolutely outstanding if
I am right.
Bernard
Date: Mon, 17 Aug 98
From: Michael Heal [email protected]
To: [email protected]
Subject: Re: slide film for macrophotography
While not 400 ASA, I'd recommend Kodak E100S, but it depends why
you asked for a 400 ASA slide film. E100S, while it doesn't have
great latitude, IMHO, does keep its EI 100 rating, contrast, and
colour at remarkably long exposures. In my experience, 10 second
exposures require no compensation. At that point I'd guess it's
faster than many EI 400 films. I've read that holds true for even
longer exposures, but haven't tried that. E100S has much finer
grain and overall better quality than the very few other slide
films I've tried.
P.S. Kodak's original marketing said there would be three versions
of this film. E100, E100S, and E100SW. I've never seen E100, the
lower-saturation version that uses the same technology. Does it
really exist? I'd likely prefer it as I generally find the colours
from most slide and colour print film too saturated and look
artificial, to my eyes anyway.
rec.photo.film+labs
From: "Only Me..." [email protected]
[1] Re: Color corrections in long night exposures
Date: Sat Sep 05 16:54:02 CDT 1998
For me, that's the attraction of night photography. Wildly differing colour
temperatures, and reciprocity failures of each layer of film produce
wonderful colours. being faithful is all very well, but I like to capture
images that make people go "wow". I purposely choose a film that freaks
under such conditions. Provia is a good one for night city scenes.
Good Luck
David
From: [email protected] (Regnirps)
Newsgroups: rec.photo.film+labs
Subject: Re: Reciprocity?
Date: 26 Aug 1998
Reciprocity (failure) in film lingo is the term used to describe that
exposure time and film density are not reciprical. In other words, its not
a straight line that describes exposure/density. We would like it to be
reciprical, so we call it a failure!
Fortunatly, the end of the curve where exposure times are short is nearly
a straight line, but people like astronomers using long exposures are
getting from a 1 hour exposure what you woyld expect from maybe 10 or 15
minutes if the relationship were linear. In many film it is noticiable on
anything longer than say 1/4 sec and you need to make a correction.
Soaking the film in hydrogen gas and no water vapor or freezing it in a
cold camera can go a long way make it more reciprocal.
Charlie Springer
From: "Fred Whitlock" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Reciprocity failure?
Date: Thu, 20 Aug 1998
Film is designed to be used under what one would consider normal shutter
speeds like a few seconds to 1/10,000 of a second or so and the film speed
(ISO rating) is assigned to that film based on its use within that range.
Actually when light is dimmer or more powerful than normal and very extreme
exposures are required the film doesn't exhibit it's normal ISO rating.
This is usually a problem with very long time exposures since the very very
fast exposures don't usually enter in to most people's photography.
Basically the film needs more light with long exposures so the exposures
need to be even longer. That's a simple laymans description of reciprocity
failure. The film manufacturers publish reciprocity tables to allow you
look up the correct compensation for long exposures. Sometimes this is
published on a data sheet that accompanies the film. Sometimes you need to
get the data sheets from the manufacturer. Good shooting.
Fred
Maplewood Photography
http://www.maplewoodphoto.com
From: "Roger" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: reciprocity failure
Date: Thu, 20 Aug 1998
This occurs at very short or very long exposures when the light reaching the
film does not give full exposure. For instance 1/8 sec may give f/2.8 but
if you changed to 8 secs at f/22 the frame might not look fully exposed and
there could also be a colour shift - often magenta or green (because not all
the layers in colour film have the same reciprocity performance). Generally
you are OK between about 1 sec and 1/10000 sec for most films, and I've
found Fuji Reala goes to 30 secs without any real problem. Some films like
Vericolor III are only recommended for 1/15 sec and shorter, while others
like Vericolor Type L (Long) are recommended for much longer exposures.
For indicated exposures of more than a few seconds I usually bracket, adding
a stop or so to be on the safe side (very short exposures are unlikely to
cause a problem unless you use high-speed multi-flash setups to freeze rifle
bullets etc). The film manufacturer can invariably supply reciprocity data
including the proper exposure compensation and colour correction filters
needed. The Kodak Professional Data Guide lists all their films.
Roger Cantwell
Date: Thu, 20 Aug 1998
From: "Bug" [email protected]
Subject: Re: Q: Shooting city skyline at night
Probably not the precise help you are expecting, but KChrome 64 works well
anywhere between 2.5 and 4 mins. Watch out for very bright light sources
(sodium etc in street lighting), and bracket like a mad person. Have fun,
the results can be stunning!!
From: [email protected]
Newsgroups: rec.photo.technique.misc
Subject: Re: Q: Shooting city skyline at night
Date: Thu, 20 Aug 1998 05:55:15 GMT
To get close to neutral color try using any of the following filters: CC30M,
Singh-Ray Flourescent type 1, Tiffen FLD., or CC20M+CC05R.
Date: Sat, 03 Oct 1998
From: "L. J. Powell" [email protected]
Newsgroups: rec.photo.technique.misc
Subject: Re: Night Exposure-Yellow Tint problem?
Ron wrote:
> I've been trying some night (sky) shots (in a rural area) and one problem > I've encountered is that many of the colour prints come out with a distinct > yellow tint instead of a "pure" black sky. > > I don't know whether this is caused by > -exposure settings > -film choice (Fuji 200) > -something in the developing > -other factors? > > Any comments would be appreciated. > > Ron
A really good candidate for causing this problem is the lab that prints
the negatives. Their equipment is adjusted assuming an average color of
the images - the average of ordinary images shot in daylight is some kind
of gray. But if you have an image that is predominantly one color, then
that color can get shifted when the neg is printed.
One sure fire way to get around this is to shoot chromes - since there is
no separate printing process, what you see is what you get. Then, if you
need a print, you can have one made but since the chrome is a faithful
replica of the original, it can be used as a go-by when making the print.
Louie J. Powell, APSA
Glenville, NY USA
From: "Mark" [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: reciprocity values
Date: Fri, 07 May 1999
From a post a while ago by John Sexton on CompuServe's PhotoForum...
Regards,
Mark
=====
From: John Sexton, 74160,2651
Welcome to the world of "reciprocity success"!!! You have to be an optimist
to work in some of the lighting situations I find myself in. Sometimes it
is truly CREATIVE photography... since I don't have a clue what my camera is
pointed at!
Here is some information that works for me with T-Max 100:
I hope this helps.
John
=====
Dr. Mark M. Tanny [email protected] wrote
From: "Only me...." [email protected]
Of course we can, however, that's not really a very polite way to ask,
is it?
However: Basically, Reciprocity law is the linear relationship
between aperture and shutter speed to obtain a given exposure value. i.e,
1/250th at f8 is the same as 1/125th at f16. Why? Because the amount of
light that reaches the film is the same. Each aperture stop on your lens
allows twice as much light to pass. Larger numbers allow less light to pass,
so f8 allows twice as much light to pass as f16. So, take the first
example: 125th at f8. If we now close down the lens one stop to f16, we
need to "reciprocate" because we've cut the light by half, so to obtain a
correct exposure we increase the shutter speed by twice the amount.
changing from f8 to f16 halved the light, and changing from 1/250th to
1/125th doubled the light. The two setting achieve the same amount of
light hitting the film, and the actions of aperture and shutter speed have
a "reciprocal" relationship. If you know the correct exposure is 1/30th
at f22, then you can work backwards to get a result without having to take
another light reading: 1/30th at f22... 1/60th at f16.... 1/125th at
f11.... 1/250th at f8... etc.
However, the law fails when very short or very long times are used. In
fact, the reciprocity law is only valid with most emulsions between 1/1000th
and 1 second. Outside these times the linear relationship between the two
variables becomes less reliable, and the further outside these times you
venture, the greater the error will be.
For instance: With colour negative film, if you need to use a speed of
one second, a good rule of thumb is to add one stop... for 10 seconds add
two stops, and for a 100 secs, add 2.5 stops.
As you can see, B+W film is the worst effected, followed by colour neg,
then the best characteristics are from colour tranny film.
However, the above figures are rough guides, and technical data on each
emulsion should be consulted if you're to be very accurate.
In the real world though, the best way to combat this problem is to
bracket ( take a shot under exposed, one at the meter reading, and one over
exposed by a stop). You can bracket as widely as you think you need to, and
the longer the times you use, the more you should bracket (2,3, or even 4
stops over and under if you're shooting something like a city scene with
lots of conflicting light sources, and changing characteristics.
One other thing that separates colour film from mono film, is that each
layer of colour film has it's own reciprocity characteristic (col film uses
separate layers to record cyan, yellow and magenta which are the
"opposites" of red, green and blue, which as you know, combine to make any
colour). This means that not only does the exposure time change, but the
colour characteristics do too. Night shots can really exaggerate the
differing colour temperatures in a street scene, and you'll get orange ,
blue, yellow lights where you thought there were only slight variations.
This is usually an advantage in such work, but in the studio, when colour
rendition is important, you should either use speeds within the reciprocity
of the film, or correct the shift with filters.
Yes: Like the above paragraph, I've experienced severe colour shifts in
long exposures. I once had green skies, and purple street lighting! It
looked cool though :-)
With mono film, I've just had badly underexposed negs. You only make
the mistake once though, and quickly learn the above rule of thumb, or if
you shoot lots of film, you end up actually knowing the correct times for
each type of film.
There have been many books written on the subject, and photo mags
regularly feature some sort of article on it at regular intervals. Also,
search Deja News for newsgroup posts on the subject, or visit the web sites
of the major film manufacturers to get tech data.
I hope the above helped, even though it ended up longer than
anticipated.
Regards,
David.
Postscript:
Ooops! That last line is misleading. By increase shutter speed, I of
course meant increase the amount of light.. by DEcreasing the shutter speed,
i.e, from 1/250th to 1/125th.
David.
Date: Sun, 26 Dec 1999
Jerry:
Astrophotographers (most are amateurs, as few professionals
image with film anymore, it's almost all done with CCD's) do
use film that is hypersensitized, and
astrophotosensitization seems to act at least somewhat in
the way that is described in the reference Nature article.
The modern version of hypersensitization used by most
professionals and amateurs involves soaking ia a mixture of
hydrogen and nitrogen at elevated temperature and pressure.
This both increases the films speed at any exposure (a minor
effect for exposures under a couple of seconds), reduces the
slope of the characteristic curve somewhat (just as
described in this article, typically an undesirable effect),
and increases fog level (not a problem if kept to no more
than od=0.4-0.5 for Tech Pan). But by far the most important
effect of astrophotosensitization is in virtually
eliminating reciprocity failure, the loss of effective film
speed at lower photon flux levels (that is, long exposure
times, 10-30-200 minutes).
As far as I can tell, the sensitization discussed in this
article is effective for short exposures, and thus is an
actual increase in the films real speed. The astronomical
sensitization is primarily (but not exclusively) an
elimination of reciprocity failure, not an increase in the
base film speed. Note that both of them, however, deal with
preventing the reconversion of Ag to Ag+, the nasty thing
which reverses the effect of the photoionization event and
makes film so very inefficient per photon. So they both
effect the same problem inherent with film, but seem to act
on a different time scale, and thus to have diferent effects.
BTW, Kodak used to make film that was naturally resistant to
reciprocity failure, without hypersensitization, the old
103a series (a for astronomical). These came from the
factory with no long exposure reciprocity failure, selective
wavelength sensitizations, high speed and a lot of grain.
"Hypersensitizing" this film had no effect, as it was
already free of reciprocity failure. This is long gone,
however. Reciprocity failure can also be virtually
eliminated by cooling the film to dry ice or liquid nitrogen
temperatures, as the initial photoionization event is not
temperature sensitive, but the recombination is a chemical
event which occurs more slowly as the temperature is dropped.
If these two sensitizations could be combined, maybe this
would give film a new life in the battle against CCD's in
astronomy. While film has a quantum efficiency of only a few
percent, CCD's range for 40-85%. 10x improvement in film
quantum efficiency would make it competitive against CCD's.
Btw, the Nature article does reference hydrogen based
astrophotosensitization, reference 19. Can anyone get the
text of this from the web and e-mail it my way?
Probably more than anyone wanted.
Rick Kelly
Tim Shoppa wrote:
From: [email protected] (Richard Knoppow)
[email protected] (Msherck) wrote:
This is NOT a stupid question and is far from trivial.
There is something called "the intermittancy effect" which is
related to, but not the same as, receprocity law failure. When film is
exposed in series of short exposures with the same total energy as a
single short exposure the resulting density will often be less than
that given by the single short exposure, but more than that resulting
from a single very long exposure, again, given equal total energy in
each. The resulting density will also vary, in a not very simple way,
with the ratio of exposure time to intervals between exposures.
For a little more on this, and on other effects of exposure and
flashing, see:
_Fundamentals of Photographic Theory_ Second Edition, T.H.James and
G.C.Higgins, 1960, Morgan and Morgan
And several other texts.
---
From: [email protected] (Richard Knoppow)
"Lee Carmichael" [email protected]@flash.net wrote:
It depends on the film as does reciprocity effect. The change in
electrical charges in the silver halide crystals which form the latent
image tend to leak off after a certain amount of time. This has
several effects. There has been a tremendous amount of research into
how to keep the charges stable. Some films, like T-Max, have
relatively little reciprocity effect compared to older films.
However, to answer the question directly, the amount of change in
contrast or curve shape will depend on the film and how extended the
exposures are. Note that there is also a short exposure effect. In the
early days of strobe, when most strobe flashes had very short duration
times (maybe 1/10,000 sec) the effect could be great enough to require
something like N+2 processing to get relatively "normal" negatives.
So, the answer is that while the effect is often detectable only
with sensitometric methods it can be visible and a significant problem
in practical photography.
...
---
From Hasselblad Mailing List:
I use Velvia a lot. But I would recommend Provia 100F. It basically has no
reciprocity failure. So your exposure length is inconsequential. I have
been using this film a lot lately in 6x6 and 4x5. Marvelous neutral color.
Green will render magnificently.
Jim
From Minolta Mailing List;
Hello,
This email message is a notification to let you know that
a file has been uploaded to the Files area of the minolta
group.
File : /RECIP.TXT
You can access this file at the URL
http://groups.yahoo.com/group/minolta/files/RECIP.TXT
To learn more about file sharing for your group, please visit
http://help.yahoo.com/help/us/groups/files
Regards,
From Rangefinder Mailing List;
[email protected] at [email protected] wrote:
If I might chime in here, one has to have some mental flexibility when
dealing with low light, for sometimes things are not as they seem. For
instance, John Sexton, who used to specialize somewhat in low light
photography, uses a 100-speed film, T-Max 100. Why? Because it is actually
"faster" in some circumstances than a 400-speed film! Tri-X has greater
reciprocity failure; so, at exposure greater than a few seconds, TMX is
actually faster than TX. It's not faster in daylight, but it's faster at
night after reciprocity failure is taken into account.
My friend Nick Hartmann, who produces lovely black-and-white work (most
recently bought for the collection of the Milwaukee Art Center) shot
indoors, at night, in very low light, uses the Summicron 50mm f/2. The
reason is because the contrast of that lens is obviously optimized for the
open apertures; it has very high lens contrast at f/2 and f/2.8; he's
tried various f/1.4 lenses but none seem to him to give him the image
quality he wants until they're stopped down past f/2.8. I suppose it's a
stretch to say that this means his Summicron at f/2 is "faster" than a
Summilux at f/1.4--it really isn't--but perhaps it's responsible to say
that he finds the former more useful.
I personally find the Pentax 50mm f/1.4 SLR lens more usable than the
Nikon AF-Nikkor 50/1.4 or the Zeiss Planar 50mm f/1.4 because the more
complex design (compound surfaces between the 4th and 5th elements)
translates to better "bokeh" or out-of-focus blur. Don't tell me that's
not an issue at f/1.4!
--Mike
From Minolta Mailing List:
Date: Tue, 12 Feb 2002
From: "Maisch, Manfred" [email protected]
Subject: AW: Shutter Speeds longer than 30 sec.
Hi Robin,
Fuji claims for the Provia 100F in:
http://www.fujifilm.com/JSP/fuji/epartners/bin/Provia100f.pdf
that there is no compensation for the reciprocity failure necessary, up to
128sec. For more than 4 min. exposure time, they recommend a +1/3 Stop
compensation.
Manfred
Date: Mon, 27 May 2002
From: "Mxsmanic" [email protected]
Newsgroups: rec.photo.equipment.35mm
Subject: Re: Fuji Velvia at night
"georgio" [email protected] a �crit...d
> uncle manic..
> what is reciprocity failure?
Normally you can reduce exposure by some factor, increase aperture by the
same factor, and still get a correct exposure; in other words, the shutter
speed and aperture are reciprocal to each other. However, in many films,
when the exposure time is very short (1/2000 second or beyond) or very long
(more than a second or two), this reciprocal relationship doesn't quite
hold, and doubling the exposure time might require more or less than an
exact halving of the aperture, and vice versa. This is "reciprocity
failure."
Velvia is a film that shows reciprocity failure, starting at exposure times
of about four seconds. See the Fuji documentation for adjustment factors.
At exposure times of 30 seconds, for example, a one-stop increase in
exposure is required, and a magenta filter is recommended to hold color
balance as well.
If this bothers you, shoot Provia 100F instead. It requires no correction
at all for exposures shorter than 128 seconds, and it has lower contrast
(important at night), and it renders artificial light sources a bit more
faithfully (although still in bizarre ways sometimes).
From: "Richard Knoppow" [email protected]
Newsgroups: rec.photo.equipment.large-format
Subject: Re: Mulitple Pops & Reciprocity Failure
Date: Sat, 26 Oct 2002
"Jeff Novick" [email protected] wrote...
> Can anyone tell me when reciprosity failure might be a factor when doing
> mulitple pops with flash units? I'm shooting with APX100 and have not needed
> more than 8 pops so far in doing closeup work. Ambient light doesn't seem to
> be a problem as it is either too dim or completely dark when I shoot.
>
> Jeff
Not very specific information I'm afraid. The effect is
known as the intermittancy effect. It is dependant on film
characteristics, on the number of individual exposures, on
the duration of the individual exposures and the ratio of
the duration to the interval between them. The effect is of
less exposure than one would get from a single exposure of
the same total light quantity. Short duration with long
interval results in the greatest loss of relative exposure.
---
Richard Knoppow
Los Angeles, CA, USA
[email protected]
Indicated Actual
1 sec...........1 sec
5 sec ..........6 sec
10 sec.........15 sec
100 sec.......200 sec
> In his workshop's John Sexton provides his tested reciprocity values for
> 4x5 TMax 100 (rated 80). If anyone has a copy that they could share I
> would greatly appreciate it.
> Thanks.
Newsgroups: rec.photo.equipment.35mm
Subject: Re: "Reciprocity": Why? & What?
Date: Wed, 28 Apr 1999
> The terms "reciprocity law" and "reciprocity failure" have been thrown into
> these postings a lot recently.
>
> I have two questions:
> 1) Can any of you adequately explain the terms "reciprocity law" and
> "reciprocity failure" without being arrogant or bragging about
> your superior knowledge?
Mono neg film: 1 sec - expose for two secs and decrease development by 10%
10 secs - expose for one minute, and decrease development by 20%
100 secs - expose for 20 minutes, and underdevelop by 30%
Colour Transparency: 1 sec = +.5 stop
10 secs = +1.5 stops
100 secs = +2.5 stops
> 2) Has any one of you actually in the real world of shooting pictures ever
> experienced problems due to film reciprocity failure, and if so, can you
> describe the results?
> need to "reciprocate" because we've cut the light by half, so to obtain a
> correct exposure we increase the shutter speed by twice the amount.
From: RICK KELLY [email protected]
Newsgroups: rec.photo.equipment.medium-format
Subject: Re: Researchers Make Faster Film
> Jerry Flanders wrote:
> >
> > On Sat, 25 Dec 1999 08:34:23 -0800,
Newsgroups: rec.photo.equipment.large-format
Date: Wed, 20 Dec 2000
Subject: Re: Reciprocity Effect
>One thing I've always wondered about (but oddly enough, never when I'm in the
>field with loaded film holders...*grin*). Let's say I have a film and subject
>which requires a 10-second exposure by the meter, and the reciprocity
>correction for this film indicates that I need to expose for 30 seconds. If I
>elected to expose using a series of 1-second exposures, would I need 10 of them
>or 30 of them? Yeah, this is probably stupid but I figured, what the heck...
>:)
>
>mjs
Richard Knoppow
Los Angeles, Ca.
[email protected]
Newsgroups: rec.photo.equipment.large-format
Date: Wed, 20 Dec 2000
Subject: Re: Reciprocity Effect
>Richard,
> Is this effect visual or can it only be "seen" thru sensitometry? I ask
>this because I have an tenious relationship with Ms Reciprocity and I have
>not seen too much of a difference either way.
>As usual,
>Lee Carmichael
>mailto:[email protected]
>
Richard Knoppow
Los Angeles, Ca.
[email protected]
Date: Mon, 18 Jun 2001
From: Jim Brick [email protected]
Subject: Re: color film recommendations
Date: 13 Jul 2001
From: [email protected]
Subject: New file uploaded to minolta
Uploaded by : [email protected]
Description : Transparency Film Reciprocity Chart
Date: Wed, 30 May 2001
From: Mike Johnston [email protected]
Subject: "Fast glass" and the Contax G Discussion
> Finally, in terms of overall picture quality, is a given lens at 1.4 better
> than at 2.0? Or, to use Leica as an example, is a current Summilux at 1.4
> better overall than a current Summicron at 2.0?
From leica topica mailing list:
Date: Fri, 16 Nov 2001
From: Jim Brick [email protected]
Subject: RE: Nocti Vignetting
John Shaw wrote:
>Oddly enough Sky&Telescope rated the ASA 100 Kodak Elite slide film as
>better for constellation photography than the 400, 800, and 1600 ASA
>emulsions a few years ago. Less reciprocity failure.
>
>John.
Then one should use Fuji Provia 100F which has NO reciprocity failure
until you get to 4 minutes.
http://www.fujifilm.com/Provia100f.pdf
Jim
Broken Links:
Photosource Reciprocity Failure pages were at:
http://www.users.dircon.co.uk/~migol/photo/data.html#d1 - broken as of 2/2003