Ahem…The Selection of Analog Photon Storage Media

(Choosing Film for Astrophotography)

by Clayton W. Kessler

all photos by Clayton W. Kessler

Let me start by admitting something, I am NOT any kind of Expert! The films that I will discuss will be from a fairly non-technical background (despite the high tone of the Title!). What I want to do is give you some starting points on film selection and relate some of my limited experience with the films that I like. I will try to relate only things that I have done by direct experience. If I do discuss films that I have not used I will tell you that this is from observation, from tales told by others or from rumor! Please keep in mind my lack of expertise and remember "Your Mileage May Vary".

The only claim that I can make is that over the last two years or so I have accumulated a large shoebox of astrophoto negatives – most of them real stinkers! I have also formed some opinions as to what makes a good astrophoto film FOR ME. I tend to take color negatives – so the majority of my opinions are of the suitability of color negative film. I have opinions on color slide films and also on black and white films – but I have taken little or none of either.

There! – now that I have told you just how unsuitable I am to even hold opinions on this subject I can get down to giving the "hot scoop" on astrophoto film! As I said – I like color astrophoto prints so I shoot a fair amount of color negative film. I probably have 35 rolls of various films in the freezer as I write this and I am thinking of stocking up! All of the film that I have shot personally has been Kodak and Fuji. All of the film that I shoot is 35mm – I don’t have a camera that will handle larger format stuff. Kodak and Fuji both have several outstanding astrophoto films – and a number of very good ones. The problem is that the companies tend to change the film on a regular basis. If Kodak still manufactured Ektapress Multispeed 640 – I would use it almost to exclusion. One of the hard lessons that I have learned is that film gets discontinued and if you find something that you like you better stock up! (I still have about 10 rolls of 640 in the freezer!)

The best news that I can give you is that grain sizes have been getting smaller for years and they get better all the time. I can remember shooting ISO 400 film (ASA 400 then) 20 years ago and a 3" X 5" print was so grainy a close look showed a pebbly texture. Enlargement to 8" X 10" resulted in a very poor looking enlargement. If you wanted to enlarge a photo you shot Kodacolor 25, or something similar. Today’s 400 and 800 speed films are easily comparable to ISO 100 speed film from 10 years ago. The grain structure is very fine and will stand a fair amount of cropping and enlargement. So – for my first suggestion, stay with 400 or 800 speed film for general astrophoto work. While ISO 1000 and even 1600 film is commonly available it is not the best choice for several reasons.

In my opinion there are three main characteristics to a good astrophoto film, Grain, Color Balance and Reciprocity Failure Rate. Grain we have discussed – it affects the resolution of the shot and how much it can be enlarged. Color Balance is the sensitivity of the film to red, green and blue. This is pretty important because it affects how the final print will look and how much nebulosity shows up in extended objects. Also stars themselves are quite colorful and a well-balanced film shows those colors to their best advantage. The final characteristic is reciprocity failure. This is the loss of efficiency of the film over the exposure time. Some films maintain a slow loss of efficiency over the exposure times typical for astrophotography. Other films loose efficiency so fast it would make your head spin. For some reason the faster films seem to loose efficiency at a far greater rate that the slower ones. While this is not a hard and fast rule, it does make a good rule of thumb. As an example, Fujicolor 1600 is a very fast film but after 10 seconds of exposure it slows considerably and after 1 minute it is gathering far fewer photons than some much slower films and this trend gets worse over time. Fujicolor Superia 400 is a much better choice if your exposure is going to be longer than 30 seconds or so. For an even more extreme example, several friends were shooting slide films at last year’s Texas Star Party. One fellow was taking 10 minute wide field exposures with a "barn door" style tracker. When I discussed film with him he told me he was using Ektachrome Elite II ISO 100. I privately felt that his "dinky" 10 minute exposures would yield very little in the developed slides. Boy was I surprised! He has a fantastic set of wide-field milky way photos with lots of stars, nebulosity and great colors! After doing some research I find that Ektachrome Elite II 100 has a reputation for a very low reciprocity failure rate. Live and learn I guess….

A list of the films that I have used will follow. This is not meant to be a comprehensive list of color negative films suitable for astrophotography – it is just what I have used. If you have some favorites that I don’t mention please TELL ME. I am open to suggestion and I like to try new stuff. Please understand that none of these photos were taken with the thought to be used in a comparison test. These are just general photos that I have taken and I am using them to illustrate my OPINIONS on these films.

Royal Gold 1000 seems like a natural for Astrophotography. It has that magic sounding "ISO 1000" speed rating and it is very common. You can get this film in almost any drug store or department store. I have used it several times and it works OK but I must admit it is not my favorite – or even close. I find the grain to be somewhat objectionable and the reciprocity failure to be quite pronounced.

I took a roll at the NCO Wilderness site at Boon Michigan under pretty dark skies and they came from the processor with a very brown tone. I was able to correct for this after I scanned the negatives but I was never satisfied with them. The photo displayed is the best one that I got from the Boon roll and it took a LOT of color balancing in Photoshop to get it to this point.

On the other hand – I know of several amateurs that use this film quite a bit and get stunning results. One fellow that comes to mind is Rich Brenz, from Cadillac. You can check out some of his shots on the NCO photo pages. I rate this film as OK overall and I would certainly use it again – but only if my more favored films were not available.

This film has been discontinued by Kodak, but I decided to include it because it has been my favorite astrophoto film to date (besides I still have a few rolls left! J ). While this film was available you had to get it from a well stocked camera store (I used Adrays’) or via mail order. It came packaged in five roll, 36 exposure, "Pro Packs".

The Ektapress films all seem to be very red sensitive and this one is no exception. Red emission nebulas jump out of the photo due to the high red saturation but the blue end is great too. M42 shows a great variation of red tones with some yellow in the center.

On the other hand, the Trifid nebula shows the characteristic blue reflection nebula above the red emission nebula while the faint red wisps to the left of the Lagoon are easily visible. I have found this film to have relatively low reciprocity failure and it takes to long exposures quite readily. Over all I would rate this film as excellent – and if anyone knows where I can buy some more LET ME KNOW!

The only reason that I have not taken many deep sky objects with this film is that I usually had Multispeed 640 available for the wide sky shots – and I like the Multispeed 640 better. That being said, I do like the results of the Lunar and planetary shots that I have taken with this film – at least in respect to the film performance! Pro 400 is available from well stocked camera shops in the five roll 36 exposure "Pro Pack". This is an excellent film and is capable of much more than I have done with it. My understanding from the Astrophotography Mailing List is that PPF400 is being discontinued by Kodak. If this film is satisfactory to you, a word to the wise would be to stock up now!

Now for the really good news! When Kodak discontinued production of PJM 640 they introduced a family of films to take it’s place. Included in this family is Ektapress 400 commonly known as PJ400. This is a relatively new film and there are no plans, that I know of, to discontinue it. It is also very close to PJM 640 in performance, reciprocity failure and color sensitivity. In my opinion they act like, and appear to be the same film. I guess that I now have a new favorite!

The red response is great as shown in the shot of the North American Nebula (NGC 7000). Lots of faint wispy red tendrils have been recorded. The Lagoon and Trifid shot shows the faint red wisps left of M8 and the blue reflection nebula in M20. This is a GREAT film and I highly recommend it for astrophotography!.

Figure 7 M8/M20, PJ400, 20 minutes, 200mm f3.5

It is available from well stocked camera stores like Adrays’ and Huron Camera in five roll 36 exposure "Pro Packs". It is also available via mail order.

I have not taken many exposures with the Ektapress 800 yet. The little experience that I have shows that the film works well but it suffers from more grain than the 400 speed version. It also seems to suffer greater reciprocity failure. Given my choice I will use the PJ400. This being said, the Kodak web site reports that the company is introducing an improved version of PJ800 with a finer grain structure. I am looking forward to getting my hands on some of the "new stuff" and trying it out!

Fuji makes some fantastic astrophoto films. When I started taking astrophotos I used Fuji Super G+ 400 as my main film. It was easy to find and highly regarded in the various magazines. The Fuji Super G+ 400 film has been discontinued recently but you can still find this film in many stores. I found quite a bit at Meijers not long ago but, be careful, some of it was outdated. One of the nice things about most of the Fuji film is their availability. I can go to most drug or department stores anywhere and get some good astrophoto film from Fuji.

Fuji films are generally not as red sensitive as the Kodak Ektapress films are. They still get a good deal of red but starfields show more blue and green tints. This can result in spectacular photos of the milky way and some nice views of star clusters and galaxies. Reciprocity failure is low and the grain is fairly small. The photo above shows a lunar landscape taken not long ago on SG+ 400. I would rate this film an excellent astrophotography film and well worth the time to try. Keep your eye out for closeout specials on this film – just check the date before you buy. Just a few years ago this was THE astrophoto film for color negatives.

Fuji Super G+ 800 is still available according to the Fuji Web Site. This film has always been somewhat harder to find than the ISO 400 version but usually a well stocked camera store has a supply. This film was the leader in high speed, small grain, color negative films. The grain structure is somewhat larger than the SG+ 400 and the reciprocity failure higher but not by much. Before I started using Kodak Multispeed 640, SG+ 400 and SG+ 800 were my favorite films for astronomy.

I really got started in astrophotography when Comet Hale-Bopp came around and I took lots of photos of the last "Great Comet" with Super G+ 800. This remains an outstanding astrophotography film and I would recommend it to anyone.

When Fuji discontinued the Super G+ 400 film they introduced the Superia line of color negative films. This includes a wonderful ISO 400 speed film that is the astrophotography successor to SG+ 400 – Superia 400. This film appears to have a finer grain structure and a lower reciprocity failure rate than the original and retains the less red sensitive characteristics typical of the Fuji Films.

If you compare this photo of the Cygnus region with the similar one taken with Kodak Royal Gold 1000 you can see the differences in the overall color tone. The Fuji Superia has more greens and blues in the star colors and backgrounds. I like this film a lot – it is easy to come by and it performs very well. I am looking forward to trying more of this film – especially on galaxies and globular clusters. Definitely give this one a try.

Superia 800 X-TRA is an upgrade to the original Superia 800. I never took any of the original Superia 800 so I have nothing to compare it too but the Fuji Web Site states that the 800 X-TRA was released in an effort to reduce the grain size. I found some interesting 12 exposure "Trial Size" rolls of Superia 800 X-TRA at the local Meijers for only $1.99 each. Generally speaking a 12 exposure roll is plenty long enough for astrophotography as the necessary long exposures make for a limited number of pictures each session.

I was pretty happy with the results of the roll that I recently tried. The grain seemed reasonably small and the colors were nice. The reciprocity failure seemed relatively low. All in all I am very impressed with this film and I will use it again. This film gets an excellent rating from me. The convenience of a 12 exposure roll was very nice – I typically develop a 36 exposure roll with only 8 or 10 shots on it so I throw away a lot of blank film. I wish other good astrophoto films were available in a 12 exposure roll.

You have no doubt noticed that I have not mentioned hypering films yet. The simple reason for this is I have never used hypered film! I have, however, formed opinions on hypering based mostly upon seeing other peoples pictures and what I have read on the Astrophotography Mailing List and other places.

Fuji SG+ 400 and SG+ 800 have been hypered by astrophotographers for a long time. The hypering process lowers the reciprocity failure and makes the film more efficient. I have seen many photos in magazines that have been taken with hypered SG+ and they are very nice. I have not seen any pictures on hypered Superia. I am sure that this is being tried. The Astrophotography Mailing List usually has posts that discuss hypering of various films (this is where most of the rumors that I use for knowledge on this subject come from).

Kodak PPF 400 and PJM 640 have been hypered with some success. BUT reports have it that the increase in efficiency is so slight that the time and effort to hyper these films is just not worth it. PJ 400 and PJ 800 are relatively new films, just like the Fuji Superia series. I have not seen any reports of how these films react to hypering.

My hypering Philosophy? I feel that there are a lot of good color negative films that are very efficient without hypering. The time, cost and effort of hypering my film, or purchasing film pre-hypered, is just not worth it to me.

I have shot a few rolls of black and white film. I thought that this film in a moderate speed would be good for lunar pictures. I have to confess that I did not have much success – and that the fault was mine in the main part. I didn’t have very much experience at the time and the pictures were over exposed, under exposed or blurry, or some combination. The biggest problem that I have with black and white is that the 1-hour photo shops cannot process it. It usually must be sent out overnight – at least – and I like to get results as soon as possible. With color I can take pictures at night, have them processed the next morning, analyze the photos for errors or problems and take more photos that night – using the knowledge gained from examining the previous nights results.

On the other hand, black and white film is necessary in order to take astrophotos with the highest possible resolution. The people looking for the highest resolution use Kodak 2415 Technical Pan. This film has a speed of about ISO 25 so it is necessary to hyper it in order increase it’s efficiency as much as possible. I have seen some stunning photos taken with tech pan and if I ever consider myself good enough I will give this a try.

All in all I like the color negative films. While some seem better than others to me, they are all very good and can be used to take very nice astrophotos with relatively modest equipment. I encourage you to give this a try, and to try different films. So much of the way a film looks and acts is based upon what the photographer likes. You should try as many different kinds as you can in an effort find the film (or films) that bring you the most satisfaction!

Good Luck and Clear Skies!