It may be that your meter/metering technique/shutter/aperture/lens/thermometer/developer/developer dilution/agitation technique are cumulatively sufficiently different from the conditions used to determine the ISO speed of the film as to require you to meter at a different Exposure Index ("EI").
If using your meter at an EI of 320 and increasing the exposure by one stop worked for you, it would be worthwhile just using an EI of 160 instead.
WRT the shots you metered at EI 400 and were unhappy with, was they lacking in shadow detail, or were they low in contrast and highlight "sparkle"? If the former, your problem was with under-exposure. If the latter, your problem may be with under-development.
That's why I asked what is the ISO when I shot at 320 but the EV is plus 1.
As for why I was unhappy, well honestly, the contrast was low and lacked the sparkle I always want.
How are you calculating exposure? Do you spot meter on the shadow textures you want to place on Zone III? If you do then the box speed of 400 ISO and development for the same 400 ISO can work quite well.
Out of curiosity, what developer and dilution did you use? Out of the mainstream developers, I can't think of one that would give particularly dull results with HP5+, unless you are using it in a way not intended. As Matt mentioned, there are plenty of other things apart from speed rating that could be wrong, and it is well worth the effort to figure out exactly what it is that is not working for you as it should.
There is in principle nothing wrong with settling on an EI of 160 for your workflow, assuming that you scan only. I would rather understand how and why I deviate from the norm, though. That gives one far greater control and enables good decisions in difficult circumstances. While it may give the best results for your current scanning setup, there is something to be said for getting the best negative, and optimising your equipment and techniques around that. In future, that would enable a better scan from the same negative, or alternatively a better darkroom print. While Mark is correct in saying that keeping development constant, one may be able to get remarkably similar looking prints from EI 50 through 800, I must point out that you will definitely see deterioration in the shadows or highlights, depending on at which end you are. Whether that matters for a particular print is entirely dependent on how important those zones in the particular image are, and how well you can print a difficult negative. HP5+ captures easily more than 10 stops of dynamic range, but to get the extremes onto paper in a way that looks natural is not always that easy.
What dorff said.
The purpose of the negative is not to give you an exciting scan or print. Its purpose is to hold all the detail of the scene necessary to make your final scan (through Photoshop adjustments and curves) or your final print (through contrast filters, burning/dodging).
Whatever EI and developing schemes get all the detail you need on the negative are the right ones.
Thanks, I never though of it that way. I usually try to get the shots I want even if it means blowing out the details because that way I don't have to spend so much time dodging or burning. Though I don't mind playing with filters.
What film speed do you like your prints best at? That's the speed you should be shooting at.
Making negatives that work well with the rest of your work flow will remove a ton of frustration in the darkroom come printing time. And to make such negatives, some testing is required.
You are probably unique in what your situation is, and if you think about it, all of these factors play into what speed you should expose HP5 at to give YOU pleasing results:
- Your lighting conditions / quality of light where you live and photograph
- Your metering technique
- Your meter accuracy
- Your lens
- Your shutter accuracy
- Your water supply
- Your film developer
- Darkroom thermometer precision and accuracy
- Your film developer dilution
- Your agitation technique
- Your printing paper
- Your paper developer
- How long you develop your paper for
- Paper developer dilution
- Darkroom 'safety level' (how dark is it really, and is your safelight safe?)
- Are you going to tone your prints or not?
There are a zillion factors that play into how you should expose your film!
Now go shoot some film, have fun, and figure out what you must do to get the results you want.
Thanks! I'm still learning, I decided to stick with HP5+ for now. At least until I have a good handle on it before going to other types.
Well, you have some advice to sieve through here! Technically, Thomas covers a great many things that you should consider, but if you are like me and have limited time juggling family life, a professional career and a few other interests, then you would want to take a few short cuts with the least risk of losing something important. So think about the following:
Change one thing at a time, until you are sure you understand how that affects you. The most important things are (in my view): Choice of developer and dilution; agitation (do not underestimate this!); developing time; temperature; exposure (including any bias/fault on your camera or lightmeter). If you add filtration, that will change a few things, especially how skin and sky are rendered. If you do not have a densitometer, and cannot make darkroom prints, it will be quite difficult to benchmark. So if you could maybe borrow a densitometer, or mail your test negs to somebody who can print or measure them for you, that would help.
The following is an easy (but tedious) way to get to more or less understand the materials you are working with. You want to know how to expose and develop while being able to maintain detail in both the shadows and highlights into the zones that are important to you. The technique I use comes from John Blakemore's Black and White Photography Workshop. You have to take something like a single-tone towel or coarse fabric - something that has texture. Flat and smooth objects like white walls and paper do not give you any means to gauge whether detail is visible or not. Colour patterns won't help either. So you take your towel, and using the zone system designation, photograph it at zones 0 through X. Develop and print (or scan) for zone V, then print all frames at the same exposure, and assess where you are in terms of visible detail. That will then give you an indication of how to expose. You could force the contrast up or down by changing the developing time, but only if you know what you are doing, and having exhausted your tests at the standard developing time. You will do this once for every film/developer combination, which is why almost all the experienced guys advocate sticking to as few as possible. Three films and three different developers already give you 9 tests to run. It grows exponentially if you have more. It might surprise you, but after having done this with FP4+, HP5+, Acros and TMax 400, I am back to exposing at box speed and developing at standard times with Rodinal 1:50, with agitation once a minute as two gentle inversions. This gives me more than enough in the negatives to work with in terms of dynamic range, and the negatives have punch and accutance when printed close to Grade 2, assuming average lighting and subject contrast. There is one important caveat: I expose for a zone, rather than averaging with the camera lightmeter. That is usually zone IV, the "high shadows", sometimes zone III. I almost never bother about the highlights, but if the contrast is high and the highlights are very important, I might meter them and reduce the developing time. Since I shoot roll film, that is the exception and not the rule. BTW, you are lost without a spot meter, either in camera or handheld.
Since there is an aversion to zeroes and ones on this forum, I will not delve into your scanning methodology. Suffice it to say that some scanners (and/or software) fare less well with black and white negatives than others. You might want to solicit advice in the appropriate forum on that topic. It took me a while to figure it out, and I am still not nearly as happy with scans than with my darkroom prints from the same negative. The upshot of this is that it motivates me to make darkroom prints, since I absolutely want to see what the negatives are capable of.
EDIT: Drew makes it sound as if it is easy to use printing techniques to salvage a negative. While experienced printers make it look easy, in reality it is not so simple. At the very least, it is time consuming. There are some scenes that are nigh impossible to expose optimally for the entire dynamic range, and then such techniques are very useful to get a quality print. But they are for most of us the exception and not the rule. You should not expose and develop your film in such a way that special techniques are required for every subject. Then you are definitely doing something wrong.
Thanks everyone for the great advice! Its so much more fun when there is so much more to learn. The possible premutation may drive some people crazy but I just love this kind of stuff!
Well, my point is not that each of those items have to be individually accounted for.
The point is that they cumulatively can make a big difference.
And that's precisely why we need to figure out for ourselves how to rate our film.
Sure, somebody else can tell us to start at 250, but then if we are interested in the best results, which I presume the OP is, (or they wouldn't be here asking), then you have to go see for yourself ANYWAY.
The idea is to save ourselves the trouble and just go do a fairly rudimentary speed test, and be done with it.
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh