Over-exposed Tri-X---to pull or not to pull? Eumig nautica, orange filter on

Jordan B Moss · September 25, 2023

Hello! I shot a few rolls of Tri-X at the water (both above water and under water) using a Eumig Nautica for the first time. I'm pretty sure it'll be overexposed but some clarification would be helpful!

1. I switched on the orange filter (switched to sun icon) because I was hoping the orange filter would help with contrast while underwater. The Nautica can only do ASA speeds 25D, 100D, 40T or 160T. My understanding is that Tri-X would normally be rated at 160. But since I had it in daylight mode, does that mean it was rated at 100?

2. By how many stops does the orange filter darken the image? I've seen the number 2/3 used--does this mean my film (which normally would have been 200) was effectively a 133 speed?

3. Anyone have experience pulling Tri-X? Would you recommend that I pull it one stop when I get it developed? I'm reluctant to do this because I usually lean toward underexposing film and then pushing it--I did this with one roll of Tri-X with a different camera and I loved the deep blacks and the heavy grain. Am I better off pulling and then potentially having low contrast or processing normally and potentially having overexposure? Which is easier to work with in post? New to BW reversal so not very sure.

I'm considering getting the least important roll processed normally and then waiting for the result before processing the rest but curious what others think.

Thank you!

David Mullen ASC · September 25, 2023

If there is an internal reflective meter, it reads the light after the filter so automatically compensates for the internal 85 filter going in, or any filter in front, just as it compensates for overcast versus sunny conditions. The 85 filter has a 2/3-stop loss.

If it has an external meter, next to the lens, it probably would be set-up to compensate for the internal 85 filter being switched in but wouldn't know if an ND filter was added in front. Just a guess.

Martin Baumgarten · September 26, 2023

The EUMIG Nautica despite its underwater design, is basically the same camera as the EUMIG Mini-3. The lens is the similar short zoom non-focus design. The meter uses an external window in front and is not TTL. The film cartridge will move the Built-in #85 Orange Filter out of the imaging path via the push switch in the film chamber.....if the cartridge does not have the Filter Notch. And TRI-X film does NOT have the Filter Notch....so it doesn't mater if you set the Filter Switch on the side of the camera to Daylight or Tungsten...the cartridge pushes the Filter out of the way. In order to make use of the built-in Filter, you will need to break off a piece of the cartridge front wall to make your own "filter notch". This is easy enough to do with a pair of needle nose pliers, or a very sharp knife.....cut down a slit on either side where the notch should be, then just break off this tab you make.

Okay now to your questions:

[1]. TRI-X will be rated at ISO/ASA 160.....and the only way to drop that rating down via adding the built-in Filter is to make your own filter notch. So have set the filter switch to Daylight....didn't do anything...the cartridge had pushed the filter out of the way, thus rating the film at ISO 160.

[2]. Yes, you are correct, it's 2/3rds of a Stop less light......IF you had a filter notch on the cartridge. But that was not the case so the film was shot without the use of the built-in #85 Filter and was rated at ISO 160. I have always made the Filter Notch on those cartridges that don't have one, IF I ever wanted to be able to make use of the Filter especially with B&W film to take advantage of the orange filter effects...absorb blue, render great sky and cloud details, and water looks great as well. TRI-X is rated at ISO 200 under Daylight and the ISO 160 rating still works fine within the film's exposure latitude, for most shots.

[3]. As far as "pull processing" TRI-X goes, yes, it can be down and still looks fine. 1-Stop will not hurt it. I have pushed it up to 3 Stops also. IF the film is over-exposed.....as a Reversal Film, processed as Reversal......you will lose detail. If processed as a Negative, it will still have details, despite having some more density in it.....unless you pull the Negative processing a bit as well....then just normal density and still have all the details.

[4]. Regarding "post digital processing", the best quality is achieved similar to Color Negative film, meaning exposing TRI-X for and processing it as B&W Negative. The "Look" is different between Reversal and Negative, so you would have to conduct a test, having a given cartridge film removed and one half processed as Reversal and the other as Negative......and compare the results. I prefer to project my films, but I do hope to digitize everything as a backup. Film backups are too costly compared to digital and in digital there isn't the generational loss that happens each time a film is duplicated another generation.

[5]. Your idea to process ONLY one of the film first...is excellent.....this way you will be equipped with the information you need to make an informed decision of how to proceed. I would examine that processed film....and if you do feel the need to make a lab processing adjustment....try it ONLY on one film first....and then examine that one....before proceeding to the others. Reversal film can not be digitally repaired in post compared to an over-exposed Negative Film, since the detail is not in the film. Processed as a Negative, it should be processed in a good continuous tone B&W Developer, and NOT in the Reversal Process without Reversal....as it would be too contrasty.

I have used TRI-X in bright sunlight.....always made use of the built-in filter, and used Neutral Density Filters to cut the light down [or Polarizing Filter, similar filter factor to some ND Filters]. I've had the effective ISO down as low as ISO/E.I. 20 on some setups.....always looked great. To use and ND filter on that camera though, you'd have to also place a small equivalent ND plastic/gel filter over the meter window port to compensate for the filter that you add to the lens.

Best of luck on your project!

Jordan B Moss · September 26, 2023

So I'm looking at the film compartment and I'm not seeing the push switch you're describing which would shut off the orange filter. Here is an image of my compartment, and then an image with some tungsten film in there. I don't see any switch poking thru the filter notch on the tungsten roll. The only thing that sticks out other than the center gate is the ASA pin. I wonder if there might be multiple versions of the Nautica and perhaps mine doesn't have that push switch? Or perhaps a prior owner removed it?

In the case that the camera may have allowed me to use the orange filter with Tri-X, would that mean it's rated at 160 - 2/3*80 = 107? In that case, I'm guessing it'd be best to pull it one stop?

I also would like to be able to project this so prefer not to process as negative. But that's great to know, I may choose to do that for a future project!

If I want to use an external ND filter or 85 filter with the nautica, do you know the thread size? Can't find that info anywhere. Also, will I have any problems screwing the PMA filter on top of an external filter? The thread seems deeper than your average filter. Is there anything special I have to do regarding water getting between the lens and the filter?

THANK YOU for all these answers, this info is very helpful!

Jordan B Moss · September 26, 2023

To streamline my question above:

Based on some further testing/examination I'm now fairly confident that the orange filter is engaged when I hit the daylight switch no matter what kind of cartridge is in there. It seems my camera is only smart enough to read the ASA notch (to tell the difference between 25D/40T and 100D/160T), but that it finds out if the cartridge is tungsten or daylight by manual switch only. It seems that the only way to have a cartridge rated at 40 or 100 is to turn on the daylight switch (which also turns on the orange filter).

Assuming my logic above (in this comment and the last) is sound, my question is this: was the film rated at 100? Or did the camera subtract 2/3 stop from 100 because of the orange filter and rate it at ~67 ASA?

Also please ignore my questions about filter thread, I was able to find the answer elsewhere.

Thanks again!

David Mullen ASC · September 27, 2023

The easiest way to find out is to load another cartridge of Tri-X and compare the f-stop it selects to what your light meter tells you, assuming you know the shutter angle. Does this camera have no manual switch for daylight versus tungsten? My only Super8 experience was with a Sankyo XL60.

Either way, if there is only a potential 2/3-stop mistake, I'd develop it normally instead of guessing.

Joerg Polzfusz · September 27, 2023

5 hours ago, David Mullen ASC said:

Does this camera have no manual switch for daylight versus tungsten?

Yes, but it is inside the film chamber - it‘s the orange switch in the above photos. (That’s because the Nautica is an underwater camera with a minimum of buttons, switches, … on the outside.)

Joerg Polzfusz · September 27, 2023

12 hours ago, Jordan B Moss said:

It seems that the only way to have a cartridge rated at 40 or 100 is to turn on the daylight switch (which also turns on the orange filter).

The camera simply assumes that all used films are 40 or 160 ASA Tungsten. It only differs between these two types. The camera doesn’t really know 25 and 100 ASA. These two values are only the effect of „Tungsten balanced films with enabled color correction filter“ (aka: the user has moved the orange switch to sun = the user has enabled the filter = there are 2/3 f-stops of light that don’t reach the film any more). But as the camera is using TTL lightmetering, it would automatically correctly compensate for all kinds of filters .

When using daylight balanced films in this camera, e.g. Vision3 50D or E100D, then the filter switch has to be set to „bulb“ (filter disabled) unless you want to pretend that you have filmed something on Mars. (As the camera‘s film sensitivity detector is rather simple, the V50D will be exposed at an okay 40ASA, while the E100D will be heavily overexposed at 160ASA.)

For b&w films like the Tri-X, it‘s best to set the switch to „bulb“ - unless you want to use the color correction filter as an orange filter (e.g. for portraits or for increased contrast when shooting landscapes or buildings).

Even though the Tri-X is officially rated as 200ASA, Kodak has notched it as 160ASA. That’s because of the Super8-standard that doesn’t define any notches for 200ASA. However, the Tri-X is working fine when exposed as 160ASA.

Jordan B Moss · September 27, 2023

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6 hours ago, Joerg Polzfusz said:

The camera simply assumes that all used films are 40 or 160 ASA Tungsten. It only differs between these two types. The camera doesn’t really know 25 and 100 ASA. These two values are only the effect of „Tungsten balanced films with enabled color correction filter“ (aka: the user has moved the orange switch to sun = the user has enabled the filter = there are 2/3 f-stops of light that don’t reach the film any more). But as the camera is using TTL lightmetering, it would automatically correctly compensate for all kinds of filters .

This is the info I was looking for! Thank you!

My Nautica (not sure if there were multiple models) doesn't have TTL metering, it has a separate light meter above the lens. So in that case I'm thinking I'll set the camera to daylight to use the color correction filter for added contrast, but then add an ND filter so that I can underexpose by 1 or 2 stops. I really love the look of Tri-X when it's pushed so I'd like to underexpose on purpose.

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13 hours ago, David Mullen ASC said:

The easiest way to find out is to load another cartridge of Tri-X and compare the f-stop it selects to what your light meter tells you, assuming you know the shutter angle.

Wish I could do this but this camera actually doesn't tell you the aperture. It only warns you if you're underexposed. I tried finding a shot that was just on the edge of underexposed to see if I could figure out what aperture was being selected but it was too imprecise.

Thank you all for your replies!

Joerg Polzfusz · September 28, 2023

16 hours ago, Jordan B Moss said:

My Nautica (not sure if there were multiple models) doesn't have TTL metering, it has a separate light meter above the lens.

Yes, you’re right. Sorry, my mistake. I’ve last used my Nautica in the year 1 or 2 BC (before Covid-19) and I use too many different cameras. ?

However, the camera knows when you have enabled the filter and automatically takes it into account for the auto-exposure. (Sorry, I have only got a German service manual.)

Edited September 28, 2023 by Joerg Polzfusz