New HP5 Plus data sheet

[Andrew O'Neill]

That new data is much closer to what I have been using for decades. Their old data was way too high.

[Pere Casals]

reciprocity corrections given by Ilford (or others) really ought to be for Zone V

Bryan, I agree in that the new HP5 corrections look calculated for Z-V, but I suspect that the older ones look to be intended more for film speed correction, this is the capability to record detail at -3 stops.

Well, this was 1 stop difference for 30s exposures...

Anyway, in night photography, and as an starting point, overexposing a bit may harm less than crunching the shadows...

Shooting some in the conditions one expects to be in gives a wealth of information - more-so than testing at home. IMO.

Yes, I agree, just making some bracketings at night one may get the sweet point, and by the way with the bracketing one goes home with the image.

Anyway making a LIRF calibration is not that weird if one likes testing, just we need to spend 3 sheets and some 2 hours.

It's straight, we develop 1 sheet at N, another one at N-1 , and N-2. In each sheet we made several contact copies from the narrow density wedge (T2115) with the exposure times we want... the rest is like always, and with that info one is able to nail the shot in any situation...

With Neopan all that was unnecessary

That new data is much closer to what I have been using for decades. Their old data was way too high.

Andrew, yes... but this also depends on how we correct LIRF. If there are several ways to meter plus personal shifts, by adding the LIRF corrections...

IMHO its is true that the old corrections tended to overexpose the mids, but it is also true that the new corrections should have a tendence to underexpose the shadows.

As we also have a dynanic range contraction with LIRF then there is no single good correction.

IMHO this matters on how we use the correction:

> if using the old correction then it had to follow a N- development to not cook mids and highlights,

> if using the new correction we have to understand that we may loss Z-III, so sometimes we may want to overexpose 1 stop, but then, in practice, we are using the old corrections...

So, perhaps, we can conclude that if our scene is not contrasty then the new correction is better, but if we have a contrasty scene then the old correction provided a safety belt, but then we may have to rely on a following N- development...

[Steven Ruttenberg]

Okay, so this sounds like a chemistry class How does all this help? I made a 30 min exposure on Tmax 100 of a mural (posted in another thread) and simply developed it "normally" in Tmax developer at 68 degrees F. From what I can see, it came out fine.

I want to get into long exposure, not only for daylight using an ND filter for rivers, streams and to remove people when shooting architecture in the city, I want to do night time photography. So, if I expose say the darkest part of the scene, that meter reading is correct to place that spot in Zone V. Let's say now, I make a long exposure of that using an ND filter that gives me say 2 hour expsoure for that point to be in Zone V. Or, I make a night time exposure that is say 2 hours using ambient light (typically a best guess for exposure times) How would I develop my negatives?

I am using Tmax100, Acros 100, Delta 100 and how HP-5 400.

Do I increase time, decrease time? How do I use the info in the data sheets? I don't want to loose shadow detail, especially in the darkest areas, but don't want to "cook" the highlights or mids as some have said.

I find all this interesting, but at the same time, I am trying to stick to the basics till this is second nature.

[Corran]

Steven, the reason this is important for HP5 especially (and other 400-speed films generally) is that they experience reciprocity failure to a higher degree. And as RF continues to increase, the contrast increases as well. So if one wants to get the best negative, it should be accounted for.

Luckily for you, T-Max 100 has pretty good reciprocity characteristics. And if your mural photograph had lowish contrast and you developed normally you might've just been extra lucky and gotten a free N+1 effect that worked for the image, and not realized why.

Moving on, once you get into really long exposures, you should really pay attention to this. Your 2 hour exposure on TMX will likely come out very thin if you don't account for RF. Been there done that. I don't have my old chart handy but I think those kinds of exposures will need a 2+ stop correction. Google searching will find recommended times and you can go from there - manufacturer charts don't go up that high as far as I've ever seen. And again, your contrast increases so take that into account.

Acros 100 generally has the best reciprocity characteristics of any film. I suppose you would do well to use it for your intended long exposures, because IMO that's it's only good characteristic.

[Andrew O'Neill]

Bryan, I agree in that the new HP5 corrections look calculated for Z-V, but I suspect that the older ones look to be intended more for film speed correction, this is the capability to record detail at -3 stops.

Well, this was 1 stop difference for 30s exposures...

Anyway, in night photography, and as an starting point, overexposing a bit may harm less than crunching the shadows...




Yes, I agree, just making some bracketings at night one may get the sweet point, and by the way with the bracketing one goes home with the image.

Anyway making a LIRF calibration is not that weird if one likes testing, just we need to spend 3 sheets and some 2 hours.

It's straight, we develop 1 sheet at N, another one at N-1 , and N-2. In each sheet we made several contact copies from the narrow density wedge (T2115) with the exposure times we want... the rest is like always, and with that info one is able to nail the shot in any situation...

With Neopan all that was unnecessary




Andrew, yes... but this also depends on how we correct LIRF. If there are several ways to meter plus personal shifts, by adding the LIRF corrections...

IMHO its is true that the old corrections tended to overexpose the mids, but it is also true that the new corrections should have a tendence to underexpose the shadows.

As we also have a dynanic range contraction with LIRF then there is no single good correction.

IMHO this matters on how we use the correction:

> if using the old correction then it had to follow a N- development to not cook mids and highlights,

> if using the new correction we have to understand that we may loss Z-III, so sometimes we may want to overexpose 1 stop, but then, in practice, we are using the old corrections...

So, perhaps, we can conclude that if our scene is not contrasty then the new correction is better, but if we have a contrasty scene then the old correction provided a safety belt, but then we may have to rely on a following N- development...

My corrections were set up so my zone III is indeed zone III. I've always gotten full shadows. Development compensation has never been necessary.

[Steven Ruttenberg]

Steven, the reason this is important for HP5 especially (and other 400-speed films generally) is that they experience reciprocity failure to a higher degree. And as RF continues to increase, the contrast increases as well. So if one wants to get the best negative, it should be accounted for.

Luckily for you, T-Max 100 has pretty good reciprocity characteristics. And if your mural photograph had lowish contrast and you developed normally you might've just been extra lucky and gotten a free N+1 effect that worked for the image, and not realized why.

Moving on, once you get into really long exposures, you should really pay attention to this. Your 2 hour exposure on TMX will likely come out very thin if you don't account for RF. Been there done that. I don't have my old chart handy but I think those kinds of exposures will need a 2+ stop correction. Google searching will find recommended times and you can go from there - manufacturer charts don't go up that high as far as I've ever seen. And again, your contrast increases so take that into account.

Acros 100 generally has the best reciprocity characteristics of any film. I suppose you would do well to use it for your intended long exposures, because IMO that's it's only good characteristic.

Will need to take some time to digest this new to me item. Doesn't seem overly complicated once you get the basics down. Thanks for the reply.

[Pere Casals]

My corrections were set up so my zone III is indeed zone III. I've always gotten full shadows.

I would ask how do you calculate/adjust that. Do you apply the correction to a +2 stops exposure time and then you underexpose the result by 2 stops ?

Development compensation has never been necessary.

Of course, the need of N- comes from the scene contrast, anyway it is clear that LIRF increases the contrast in the negative, because shadows have way more LIRF than highlights, so it's easier that a N- contraction is suitable in LIRF conditions, because then it's way easier to blow highghts if still wanting shadow detail.

Note that it can happen that highlights in a shot may not experiment any LIRF, while shadows are in severe LIRF, in this shot (https://www.flickr.com/photos/125592...n/photostream/) for example I found that.

[neil poulsen]

Will need to take some time to digest this new to me item. Doesn't seem overly complicated once you get the basics down. Thanks for the reply.

For color film, these manufacturer posted compensations make sense. Film development is well defined, and it's an easier matter to define compensations that result in pleasing photos.

But for black and white, I would need to know the methodology by which these numbers are arrived.

It seems to me that reciprocity failure is a failure in film speed -- additional exposure is needed, as more light is required for adequate exposure. Film speed is determined to obtain proper shadows, so what Steven has suggested above makes sense.

Of course, exposure is only half the story. One also needs sufficient development to obtain good highlight details. So, it's interesting to me that Steven has found that no compensation is needed in development time, as one adjusts for reciprocity failure.