View Full Version : Moonlight film

Kirk Gittings
30-Nov-2005, 12:06
A good friend of mine (and a very accomplished large fromat photographer) William Stone has a unique problem. He needs to document a lunar archeo-astronomy site where a shaft of moonlight hits a petroglyph. He needs this in color and he needs relatively short exposures (like maximum 2 minutes). This is more for a scientific purpose than art. You can see his work at:


I have not been of much help. I suggested that he turn the flash off (haha) and use a high speed color negative film.

What would you do?

Steve J Murray
30-Nov-2005, 12:17
Astronomical photographers "hyper" their film, which I think is exposing it to hydrogen gas, which increases the sensitivty quite a bit. Here's a link to an outfit that sells hypered film:


george jiri loun
30-Nov-2005, 13:48
Hypered film is used for very long star skies exposures (tens of minutes). What's his problem exactly? Using normal films (100 - 400 ASA) with exposure up to 2 minutes is no problem with moonlight.

Steve Feldman
30-Nov-2005, 13:58
Maybe I'm crazy (as an LFer I guess that's a given) but doesn't the earth move during a 2 minute exposure? And the moon moves also. I've been told that even a 10 second exposure of the moon itself will cause a movement blur. Seems to me that shaft of light would move around during a 2 minute exposure.

Scott Davis
30-Nov-2005, 13:59
He might want to try a tungsten-balanced film with a tungsten-daylight filter, to help out with the reciprocity and color-shifting issues. It is my understanding that most tungsten-balanced films have a much greater reciprocity tolerance and much less color-shift at a longer shutter speed than do daylight balanced films. Some daylight films need correction with anything slower than 1/10th of a second.

The other really arcane way of dealing with this is to shoot it as b/w color separations, then make carbro prints. That solves the color shifting due to reciprocity.

John Berry ( Roadkill )
30-Nov-2005, 14:11
You might contact this guy.

Kirk Gittings
30-Nov-2005, 14:32
"Using normal films (100 - 400 ASA) with exposure up to 2 minutes is no problem with moonlight." His testing suggests that an 100 asa film would require a 15 imute exposure.

"Seems to me that shaft of light would move around during a 2 minute exposure." It is simply a question of how muchmovement is acceptable and he thinks two minutes is acceptable.

I do not think that extreme color accuracy is a necessity. Has anyone out there experimented with pushing color negatve film?

george jiri loun
30-Nov-2005, 14:54
What does he want to photograph? The moon? The petroglyphs in the moonlight? Both? A full moon, a quarter moon?

Paul Butzi
30-Nov-2005, 15:02
It sounds to me like this is a problem of photographing by moonlight.

If I recall correctly, the moon is magnitude -13 and the sun is magnitude -26, so that illumination from the moon is something like 17 or 18 stops dimmer than illumination from the sun.

The rule for sunlight is (1/iso) at f/16.

So if you multiply that exposure by 2^17 or 2^18, you'll be in the ballpark. That gives you a range of (262144/iso) at f/16 to (131072/iso) at f/16.

If you're using ISO 1600 speed film (or a digital camera like the EOS 5d set to 1600) that gives you roughly 164 seconds to 82 seconds, not allowing for reciprocity. Two minutes falls neatly between those two values, so I'd guess that two minutes at f/16 with ISO 1600 film would be about right.

You can open up a couple of stops and cut the time some, or use slower film. That is, 800 speed film, 2 minutes at f/11, 400 speed film 2 minutes at f/8.

I'd suggest that checking my math might be in order before using those numbers.

Sounds like an interesting task - photographing the petroglyph by moonlight to show the alignment. That's pretty cool.

Nathaniel Paust
30-Nov-2005, 15:15
For long exposures, I usually go for Astia. I've done long-exposure astrophotography up to about 15 minutes with it unhypered and it has really nice reciprocity characteristics.

A few other things...
1) The moon is going to move about 1-moon-diameter in 2 minutes, so he'll want to either make sure that doesn't matter in the picture or chose a wide enough lens that it can't really be seen.
2) Polaroid film has horrible reciprocity, so he shouldn't expect to be able to proof the scene beforehand.

30-Nov-2005, 16:02
Rent, beg, borrow, steal, or buy a Canon EOS 1DsMkII with a 50mm f:1.0 lens. One of the secrets of photography (as well as for life) is to do a job right by always using the right equipment.

Michael Heald
30-Nov-2005, 16:33
Hello! I am confused if the moon will be in the picture, or whether the archeological site alone will be photographed. If the moon is to be included, then the motion of the moon will need to be taken into account, and a short enough exposure to ensure that the moon is not blurred will need to be made. If just the archeological site will be photographed under a shaft of moonlight, a longer exposure can be used, since there will be no concern about blurring of the moon's image.

Remeber Ansel Adam's famous photograph "Moonrise" was photographed at sunset with an 8x10 camera with a #15 filter, with a Cooke Triple Convertible lens at 1 second and f32 with ASA 64 B&W film!

In any case, for color film, astrophotographers tend to use E100 and Ektachrome 200. E100 is available in 4x5. Both films can be pushed two stops easily. The reciprocity characteristics of both films are excellent.

Unfortunately, color print films will have up to two stop loss, even at two minutes exposure. Films like Portra 800 have limited benefits over pushed Ektachrome or E100.

Two books may be helpful. Michael Covington's "Astrophotography for the Amateur" and Robert Reeve's "Wide-Field Astrophotography" provide excellent discussion of films and exposures for all types of astrophotography, including various types of lunar atrophotography.

Best regards.


Jerry Thirsty
30-Nov-2005, 17:05
The table in Kodak's "Existing Light Photography" lists a starting point of 30 seconds at ISO 100, f/2 (or equivalent), but this doesn't take into account the reciprocity failure. This seems to jive approximately with my recollections of shooting moonlit scenes by trial and error. From your description, it sounds as though he is expecting a beam of moonlight to be coming through an aperture of some sort (window, or cleft in the rocks?) and falling on the face of the petroglyphs. If the goal is to make the beam of light visible in the air, maybe something that would add a fog to the air would help. A fog machine if power is available, dry ice in water or some sort of fireworks if it isn't. And obviously the beam will be brightest under a full moon.

Jorge Gasteazoro
30-Nov-2005, 17:17
Hmmm....excuse the stupid question, but how the hell is a viewer going to know it was illuminated by a shaft of moonlight? Are the moon and the petroglyph going to be in the same shot? If so, doesnt this preclude a "shaft" being present? I have yet to see a "shaft" of moonlight illuminating anything so I am curious to see what one looks like.... :-)

If it is just moonlight going through a hole, what the heck is wrong with painting with light? Heck, why not just do it during the day, I am sure the sunlight would be a better choice...... :-)

Kirk Keyes
1-Dec-2005, 10:24
If it is for scientific purpose, then does film format matter? And I assume we are photographing the pattern of the moonlight as it illuminates the petroglyph.

Then us 35 mm with a fast lens, and then try one of the latest tranparency films from Fuji, as they have really low reciprocity failure. Check out Kit Coulter's web site on night time photography. He's done a lot of film testing and he recommends Provia RDP III http://home.earthlink.net/~kitathome/LunarLight/moonlight_gallery/technique/reciprocity.htm
I've heard that the new Velvia 100F works well to, but that may be too contrasty.

Kirk - www.keyesphoto.com

David A. Goldfarb
1-Dec-2005, 10:42
I'd be thinking Provia 400F rollfilm pushed two or three stops and would run some tests, since even if the astronomical event only occurs at a certain point in the year, moonlight happens every clear night.

Recently I was photographing something on the old Fuji RMS (still have about 20 rolls of 120 or so), which was supposed to be pushable to EI 1000 with a 4-stop push. I never liked it past 400 (2-stop push), but this was happening at twilight, and it was a little behind schedule, so darker than I had anticipated, and the only choice was to go for the "Hail, Mary" 4-stop push. I just had the film processed a couple of days ago, and the exposures were fine (not so sure about the images, but that's a different issue--I was panning a moving barge at about 1/5 sec. with a 360/5.5 Tele-Xenar wide open and a 6x7 back on my Tech V--the results were "interesting"). In any case, I'm fairly sure that Provia 400F at 1600 will give a better result than RMS at 1000, and RMS at 1000 is better than I expected.

Kirk Gittings
1-Dec-2005, 12:33
"Hmmm....excuse the stupid question, but how the hell is a viewer going to know it was illuminated by a shaft of moonlight?"

The quality of the question aside.

The "client" a scientist will be present and would know if it was faked. The site requires a difficult 1500 ft ascent up a butte. Permission to visit this site is very restricted and must be applied for like a year in advance. The date is very important for the test so there is no ability to do a film test on site before hand and there is no time to bracket exposures. You have to get it right the first time or wait a year. Hence my suggestion to shoot color negative fim, which I do for twilight shots all the time with no braketing but of course with much brighter light sources..

Kirk Gittings
1-Dec-2005, 12:38
This is the project.

www.solsticeproject.org/lunarmark.htm (http://www.solsticeproject.org/lunarmark.htm)

Jorge Gasteazoro
1-Dec-2005, 12:55
Ah, even though you did not like the quality of my question, it makes a lot more sense now. This is pretty much the negative of a sun dial... :-)

As was stated above, I would go with a hypersensited film, show up a day or before to the region and make some test exposures on the ground with a similar slab of rock projecting the shadow. Alternatively I remember reading about latent image intensification, where you exposed the latent image to a green light if I recall correctly after the exposure. It would be a matter of testing on a moonlight exposure see if it works better than hypersensitized film. I would not go with color since you are pretty much locked with development choices and tricks... :-)

David A. Goldfarb
1-Dec-2005, 13:34
Why would the film test have to be done on site? You just need to know what the exposure for moonlight is with the film you're using under similar conditions (phase of the moon, cloud cover).

Kirk Keyes
1-Dec-2005, 13:59
"Why would the film test have to be done on site?"

This is a good question. Even just going to a similar setup would work. Wouldn't have to be Fajada Butte.

"You just need to know what the exposure for moonlight is with the film you're using under similar conditions (phase of the moon, cloud cover)."

If you are planning on shooting on Dec. 15, then it's kind of late for that, as the moon is new right now, and there will not be a day before the 15th when suitable testing could be done as even the couple nights before full moon, the moon will have risen before sunset.

But you may want to try some test shots the night before after sunset, the moon will be higher, and about the same brightness, so all you should have to do is account for atmospheric effects. My calcs indicate the moon will be about 14 deg above the horizon 30 minutes after sunset on the 14th and about 4 degrees on the 15th.

Thanks for the paper link above - I was goingto ask if it was at Chaco.


Paul Butzi
1-Dec-2005, 16:30
The date is very important for the test so there is no ability to do a film test on site before hand and there is no time to bracket exposures. You have to get it right the first time or wait a year.

Others have already pointed out that you can, of course, do tests during full moons in conditions that duplicate the site, in advance. You can go to the site having already worked out most of the details.

Beyond that, it's perfectly possible to bracket, even if you don't have time to make multiple exposures one after the other.

I checked the rule book, and it does not say that a photographer can only use one camera at a time.

Go there with four SLR's. You can even rig a tripod with a horizontal or vertical bar and multiple heads. Set the cameras for different exposures. When the moonlight hits the petroglyph, trip the shutters all at the same time. If necessary, you could actually have more than one person on hand so that you don't have one person frantically trying to drive multiple cameras.

David Luttmann
1-Dec-2005, 16:51
While most of the film I used to hyper was Kodak Tech Pan, I did process some Kodak PPF400 when it was available, along with some of the old Ektachromes. Hypering film that is only going to be exposed for 2, maybe 3 minutes is not going to give much of a speed advantage.....at most a half stop if you're lucky. As well, you'd have to do some tests with regards to how long to hyper each different film you may work with. Base fog and color shifts between layers can be a real problem when hypering color film. Storage is also an issue. Hypered film looses sensitivty when exposed to humidity. That is why I often went with the cold camera approach as it locked in color and lessened the chance of massive color shifts.

Unless you have a great deal of experience in hypering the films you choose, the results will in all liklehood be poor. Your best option is to go for a neutral chrome like Astia, which holds up well with regards to reciprocity characteristics, especially in short exposures less than about 4 minutes, and use a digital SLR to see how well your metering really is.

But don't bother hypering.....at best, the chrome films suggested will only benefit by about 3 stops....but that is only in exposures of 15 to 20 minutes or more. It is not relevant here.

You may want to to choose a digital capture device to benefit you in two ways:

1) Knowing you've got the shot

2) Accurate color without having to worry about shifts between layers during your exposure.

Best of luck.

Kirk Gittings
5-Dec-2005, 18:40
from william stone:

Thanks very much for posting the moon-lighting inquiry on the Large
Format forum. I appreciate your doing that. As expected, some of the
responses were off target, but there were a few helpful ones in
there as well.

I've since come across some helpful info on the web, including:

tm which has a lot of good technical info, and

http://www.mkaz.com/photo/tools/moonlight.html which gives some exposure

I've pretty much decided on (still working on the plan, however) using 4

(I think 4 tripods is about as many as I can haul up there -- I'm also
doing some surveying work on the butte on this trip and need to get about
75 lbs of survey equipment, plus cold-weather camping gear, plus
photography equipment hauled all the way up) -

I think I'll use:

one 35mm and three Pentax 6x7s (from my medium format days)

I think I'll shoot the same film and exposures on all 4 cameras (have the
cameras all lined up, different focal lengths, of course - so slightly
different views, and trip the shutter one after the other, then close the
shutters a minute or 2 later in the same sequence); then process the 35mm
film first and decide how much to push process...then process the 6x7
films one roll at a time, fine tuning processing as I go.

I think that, from my research, the best bet for film is going to be
Provia 100F, pushed 2 stops as a starting point.

I still need to compute the speed of the shadow's movement across the
petroglyph so I can determine just how long of an exposure I can live
with. I'm hoping that 1 minute, and prefereably even 2 minutes will be

I've got an inquiry in to find out the distance from the edge of the slab
that casts the pertinent shadow to the spiral. Since I know (from astro
software) what the angular speed of the moon is (how many minutes of time
per degree of movement), I can then figure out the horizontal speed of
the shadow as it moves across the spiral. Fun stuff to work on.

Still fleshing all this stuff out...now, if the weather will just

Thanks again for the help.

best, Bill