B&W S8 in new chemistry

[Freya]

I'm trying to get my head around the changes in chemistry for Plus-x and tri-x.

My understanding is that both the older and newer films react the same way if put in the same chemicals so it's really the changes in chemistry I need to worry about.

I have some old rolls of plusx but these will be 100 ASA in the new chemistry just like new rolls right?

The Tri-x is 200ASA in the new chemistry. Cameras will expose this as 160ASA. How noticeable is this overexposure? It seems like about 1/3 of a stop overexposure? 64T has a similar problem, (I guess more like 1/2?). Do you think I could just "wing it?".

If a camera was adjusted for 64t would it also give better results for triX?

What is other peoples experience here?

love

Freya

[MIKI-814]

I'm trying to get my head around the changes in chemistry for Plus-x and tri-x.

My understanding is that both the older and newer films react the same way if put in the same chemicals so it's really the changes in chemistry I need to worry about.

I have some old rolls of plusx but these will be 100 ASA in the new chemistry just like new rolls right?

The Tri-x is 200ASA in the new chemistry. Cameras will expose this as 160ASA. How noticeable is this overexposure? It seems like about 1/3 of a stop overexposure? 64T has a similar problem, (I guess more like 1/2?). Do you think I could just "wing it?".

If a camera was adjusted for 64t would it also give better results for triX?

What is other peoples experience here?

love

Freya

Forget that mess with the Tri-X ASA, because it is really a 160 ASA film and not 200. It will be perfectly exposed as 160 (by experience).

About the 64T, I don't understand what is the problem apart from the fact that many cameras are not able to read a 64T cartrdge automatically (but many others do). Which model is yours? Tell us and will try to tell you how it would expose the varius stocks.

Anyway, you cannot set the camera for ASA 64T and expect any good result for the TRi-X...

[paul]

Forget that mess with the Tri-X ASA, because it is really a 160 ASA film and not 200. It will be perfectly exposed as 160 (by experience).

That is probably a result of the light loss by the prism and lens; you need that extra 1/3 stop exposure because of the loss of light.


Paul

[Freya]

Anyway, you cannot set the camera for ASA 64T and expect any good result for the TRi-X...

*giggle*

I meant if I open up the camera and adjust the auto meter to read 40ASA as 64ASA. That would have a knock on effect with all other filmstocks of course, as the meter would now read a half stop faster or something like that.

The cameras I would probably use would be a canon 318M (my throw it in a bag and forget about it cam) or either a Bauer c107XL or Bauer c108 as those are my 3 fave cameras with internal metering at the mo.

love

Freya

[Freya]

That is probably a result of the light loss by the prism and lens; you need that extra 1/3 stop exposure because of the loss of light.

Paul

But surely the camera metering is already compensating for this, especially if it is ttl metering! ;)

It may be that even reversal has enough lattitude to deal with that one third of a stop, or peoples cameras are so far gone after all these years that the metering isn't that bang on anyway or we don't have the magic eyes to see the 1/3 stop difference? ;)

It could also be that labs have adjusted their timing?

Anyway that appears to be 2 votes for no problem!
Anyone else have experience?

Kodak seem to imply the problem is more with plus-x where there is a full stop difference, which makes me lean more to tri-x too.

love

Freya

[David M. Leugers]

Tri-X reversal is ASA 200 in daylight and 160 ASA under tungsten illumination. Automatic exposure S-8mm cameras rate the film at ASA 160. If the daylight is not too bright, you will get acceptable exposures at 160ASA that your camera uses because the difference between 160 and 200 ASA is just less than 1/2 F stop and the latitude of the film can handle that. I personally prefer to expose at 200 ASA under daylight by setting the exposure manually.

For the new chemical development process, it does not affect Tri-X at all, and all Plus-X (new and old formula) will need to be exposed at 100ASA. If you have Plus-X developed in the old process, expose at 50ASA no matter if you are using the newer or older stock. At this late hour, I go for the new process to eliminate any mistakes but I make sure that I identify the old Plus-X rolls are to be processed in the new chemicals at 100 ASA.

[Freya]

Thanks David!

That makes total sense.
Presumably trix is the same speed as always then!
I forgot that B&W film was all back to front and blue sensitive!

Presumably this also means that tri-x was always 200ASA in daylight and hasn't moved and people have always had this problem and just ignored it!

Does this mean that the daylight filter is disabled too (to make it work at 160T always?)

So I guess the answer is don't worry be happy!

love

Freya

[MIKI-814]

Forget that mess with the Tri-X ASA, because it is really a 160 ASA film and not 200. It will be perfectly exposed as 160 (by experience).

That is probably a result of the light loss by the prism and lens; you need that extra 1/3 stop exposure because of the loss of light.

mmm but don't Super8 cameras such as most modern Canon's compensate for that? The same 1/3 stop loss rule would apply for the 64T, but we know this stock is perfectly exposed at ASA 64, not as ASA 50 :?:

[paul]

Forget that mess with the Tri-X ASA, because it is really a 160 ASA film and not 200. It will be perfectly exposed as 160 (by experience).

That is probably a result of the light loss by the prism and lens; you need that extra 1/3 stop exposure because of the loss of light.

mmm but don't Super8 cameras such as most modern Canon's compensate for that? The same 1/3 stop loss rule would apply for the 64T, but we know this stock is perfectly exposed at ASA 64, not as ASA 50 :?:

I always use an independent lightmeter, that's why thought it would be wise to give the film some extra light by underrating the asa. But if the TTL meter is used, then this doesn't apply. The TTL meter will take that in account. I was thinking too much in terms of external metering.

Best regards,

Paul

[MIKI-814]

Does this mean that the daylight filter is disabled too (to make it work at 160T always?)

Super8 B&W films are "Daylight", and Kodak cartridges for Plus-x and Tri-x are notched as "Daylight" so they disable the filter automatically (at least in the Canon's). Sensitiveness of the films themselves do not change with the filter "in" or "out": When a film's ASA is 200D/160T means that it is slightly less sensitive to tungsten light that it is to sunlight (due to UV rays and those things), and not directly related with the filter. Your B&W film without the filter, will act as 200 ASA under daylight, and also without the filter as 160 ASA under bulb lighting.

So I guess the answer is don't worry be happy!

You're right 8)

[paul]

When a film's ASA is 200D/160T means that it is slightly less sensitive to tungsten light that it is to sunlight (due to UV rays and those things), and not directly related with the filter. Your B&W film without the filter, will act as 200 ASA under daylight, and also without the filter as 160 ASA under bulb lighting.
You're right 8)

That's usefull information!

Thanks,

Paul

BTW, what's the latitude of this film?

[aj]

I always use an independent lightmeter, that's why thought it would be wise to give the film some extra light by underrating the asa. But if the TTL meter is used, then this doesn't apply. The TTL meter will take that in account. I was thinking too much in terms of external metering.

Best regards,

Paul

Then it still doesn't apply. If you have the ISO set and read the aperture for the shutterspeed the camera is running on then you just take the aperture reading from the meter and adjust the aperture on the lens. The numbers on the lens barrel are in the right position. The max opening is also OK and true with the prism in the beam.

[paul]

If you corrected the shutterspeed with a third stop (as here in this example) you can just read the aperture from your meter and use that. But somewhere, with external metering, the light taken away by the prism and lens has to be taken in account either via the aperture, shutterspeed or asa.

Kind regards,

Paul

[aj]

The camera and lens manufacturer have put the numbers in the right place. When it is on 2.0 it has effective opening of 2.0 and brings this onto the film. They have compensated for the light loss in the beamsplitters or where ever like coatings and glass-transmission-rate at design time. 30 years ago.

[paul]

The camera and lens manufacturer have put the numbers in the right place. When it is on 2.0 it has effective opening of 2.0 and brings this onto the film. They have compensated for the light loss in the beamsplitters or where ever like coatings and glass-transmission-rate at design time. 30 years ago.

Then the aperture settings are T-stops?