Testing photographic paper

Andreas1 · 2010-07-04T22:14:23+00:00

Gutenabend, kann mir jemand sagen ob ich die famose Dichte von 0,04 log, über den Papierschleier messen muss oder über Papierweiß (Rückseite von Papier)? Al...

Andreas1

Good evening, Can anyone tell me whether I should measure the famous density of 0.04 log using the paper veil or the paper white (the reverse side of the paper)? In other words, where should I set the densitometer to zero? I need to calibrate my lab exposure meter and I’m not sure how to do it. Thanks and best regards, Andreas

cfb_de

Hi Andreas,

can anyone tell me whether I need to measure the famous density of 0.04 log using the paper veil or using paper white (the reverse side of the paper)? In other words, where should I zero the densitometer? I need to calibrate my lab exposure meter and I’m not sure.

This results in a linear shift of the curve: if you want pitch-black shadows, you include the paper haze (if present, but that’s another matter). If you want brilliant highlights, you should leave it out. I am constantly amazed at the questions that get asked. And especially by who is asking them. The number of people who can *see* a curve shift of 0.04 logD is likely to be very close to zero. Measurement technology is useful and important. But it is not an end in itself. Best regards, Franz

sputnik

Hi Andreas,
can anyone tell me whether I need to measure the famous density of 0.04 log using the paper veil or the paper white (the reverse side of the paper)? In other words, where do I need to zero the densitometer? I need to calibrate my lab exposure meter and I’m not sure how.
This results in a linear shift in the curve: if you want pitch-black shadows, you include the paper haze (if present, but that’s another matter). If you want brilliantly bright highlights, you should leave it out. I’m always amazed at the questions people ask. And especially who’s asking them. The number of people who can *see* a curve shift of 0.04 logD is likely to be very close to zero. Measurement technology is useful and important. But it’s not an end in itself. Best regards, Franz

Hello Franz, It surprises me too that such questions are asked. What surprises me even more, however, is the fact that you believe a ‘grey scale’ of 0.04 cannot be detected. A blind person with a white cane can see that – at least if you’re assuming paper white (which was what the question was about)! After buying the Heiland Controller, I got an RT112 so I could match different papers as precisely as possible, and I was actually surprised by how dark a supposed ‘just not quite paper white’ – i.e. 0.04 logD – really is! To the naked eye, the first grey scale step definitely looked lighter. That said, such a densitometer really isn’t necessary, but the 35 euros didn’t make up for it either. Incidentally, the RT112 displays the readings absolutely accurately; I checked it using a grey scale wedge freshly calibrated by Jürgen Heiland. BTW: I would never dream of zeroing my device against the back of the paper. Best regards, Siegfried

cfb_de

Hello, namesake, I didn’t mention the back of the paper either. Try making two enlargements: one with and one without compensation for the ‘paper haze’. Hang them about two metres apart in front of a white wall and ask unbiased observers for their feedback on any differences. I guarantee you that only a vanishingly small number of observers will notice the real difference. Why do I say that? Because I’ve already tried it. Both prints sold exactly as well at the exhibition (limited to ten, ten of each sold). We precision-minded types, spoilt by measurement technology, might spot it (perhaps). But then again, we do go on and on about supposedly visible twelfth stops in split exposures... Best regards, Franz

sputnik

Hello, namesake, I didn’t mention the back of the paper either. Try making two enlargements: one with and one without compensation for the ‘paper haze’. Hang them about two metres apart in front of a white wall and ask unbiased observers for their feedback on any differences. I guarantee you that only a vanishingly small number of observers will notice the real difference. Why do I say that? Because I’ve already tried it. Both prints sold exactly as well at the exhibition (limited to ten, ten of each sold). We precision-minded types, spoilt by measurement technology, might spot it (perhaps). But then again, we do go on and on about supposedly visible twelfth-stop differences in split-exposure... Best regards, Franz

Hi Franz, Your example isn’t an argument, because that could be applied to pretty much ALL the subtleties of enlarging. For the vast majority of viewers, probably even to glaring mistakes. I once sold a print that I considered a reject – one I’d preferred to redo straight away for myself – for a hundred quid. Whether a third party likes something or not, whether they spot differences or not – these are absolutely not quality criteria for me. And I can definitely see a one-tenth stop difference in the positive process. Perhaps not with EVERY subject and, of course, only in comparison. That’s clear. But that’s why such subtleties don’t get overlooked. It has absolutely nothing to do with measurement technology. I judge and evaluate PURELY VISUALLY, which is why, for example, I just can’t warm to the new MCC, no matter how good it may be in terms of measurement. The look doesn’t suit my personal taste. And that’s all that counts. Fortunately, I take photos purely for pleasure. Sunny regards, Siegfried PS: That bit about the back of the paper wasn’t meant for you – sorry.

cfb_de

Hello Siegfried, If you can visually distinguish a difference of one-tenth of a stop, you should visit the nearest university eye hospital, have your eyes certified, and get them entered into the Guinness Book of Records. This difference in brightness exceeds the ‘technically’ possible capabilities of the human eye. Our eyes have a fairly wide dynamic range when it comes to brightness values, but a rather modest resolution in terms of brightness. On the other hand, we are one of the few life forms capable of seeing colours. Our colour resolution is also modest, because we have a brain for real-time processing. We can barely perceive a 100K colour deviation, whereas our sense of touch can certainly detect this 100K from the same distance to the object :( Best regards, Franz

sputnik

Franz, Just a quick note. I’m in a rush. When I take a series of exposures with 1/10 f-stops on a piece of paper, I can definitely see the differences in brightness, and I’m absolutely convinced that anyone else can see them too, provided their eyesight hasn’t expired yet. But actually, it doesn’t really matter. As they used to say so nicely in the GDR – From each according to their ability, to each according to their needs. Best wishes and good night, S.

cfb_de

Siegfried, In a direct comparison using a greyscale chart, that is of course possible. But when using a print with many shades of grey across the surface, it simply isn’t possible anymore. That’s what I was getting at: test charts have as much to do with applied photography as the Pope has to do with the practicalities of having children. And that’s without even bringing Ulbricht into it: there’s really no need to ‘catch up without catching up’. Best regards, Franz Siegfried B.

sputnik

Siegfried, In a direct comparison using a greyscale chart, that is of course possible. But when using a print with many shades of grey across the surface, it simply isn’t possible anymore. That’s what I was getting at: test charts have as much to do with applied photography as the Pope has to do with the practicalities of having children. And that’s without even bringing Ulbricht into it: there’s truly no need to ‘catch up without overtaking’. Best regards, Franz Siegfried B.

My dear Franz Siegfried, I must speak up again, as I cannot let this stand. Please, no insinuations. I don’t make grey scale prints and I don’t photograph test charts! When I speak of an exposure series, I mean a series of 3 or 5 graduated exposures of the part of the subject that I consider crucial for the base exposure, all on ONE sheet of photographic paper! This is also known as a test strip. And when I work my way towards what I consider the optimal exposure time (and I do do this, particularly with the Heiland Split), I can see, especially in portraits, a difference of 1/10 of a stop – if I choose such a small increment, which is very rarely the case. Full stop. If YOU don’t see that, that’s fine too, of course. Just don’t generalise about people in general. However, I don’t judge my test strips from a distance of 1 metre. Perhaps I haven’t mentioned that fact yet. Yours sincerely, S.