highscore
Hi everyone,
I’m trying to test my films. However, I don’t have a densitometer.
My assumption: The exposure times for magenta and yellow on split-grade film should be the same. Accordingly, density 0.7 = Zone 5 = Grade 2.5
My situation: The exposure ratio between magenta and yellow is currently often m=60 sec, y=6 sec
My test setup: I photographed a black sock and a white handkerchief in daylight, in the shade, using a tripod, taking three sets of three photos to obtain three test strips of three images each (exposure n-1, n0, n+1). I developed these once using my standard process, once with 10% longer exposure time, and a second time with 20% longer exposure time. My split is 60 and 3, all at 60.
Result: Yellow has increased but has not caught up with Magenta.
Conclusion: I have not exposed enough test negatives. I need to repeat the test with extended times to find the point where I achieve a longer exposure time for Yellow than for Magenta.
I’ll reduce the determined time by about 10% again, as slightly underdeveloped negatives print better.
Right. Now I’m curious to see if I can achieve a usable result with this method.
What’s your opinion?
Let’s see if you nail me to the wall.
Wolf_XL
... you might as well try measuring a distance without a tape measure. Measuring without a measuring tool isn’t really measuring at all, but merely guessing, so it won’t work... For a start, you don’t even know whether the densities in your negative behave as they should...
Urnes
Your assumption is based on the yellow and magenta filters having the same density. You also need to know what the maximum values actually are. You were trying to do two things at once that, at first glance, have nothing to do with each other.
So first, load the film (www.fotografie-in-schwarz-weiss.de/sw-fotografie/filme-eintesten.html). And then see what can be improved in the print. Why use a split grade when I end up at grade 2.5 with 70M anyway? Sure, there’s always the odd negative where I have to do some fine-tuning, but the rule should be that I load the negative and can print with a relatively constant gradient.
Regards, Sven
highscore
Hi Wolf
Well, I can measure distances using just a string, or even a plumb line in this case.
You can measure without a tape measure, as long as you stick to your own reference system.
Of course, I’d like to have better negatives so I can work more quickly in the darkroom.
But they don’t have to be technically perfect. Too much measuring kills the fun.
And I don’t have to earn a living by producing perfect (lifeless) images. If I did, I’d be using Photoshop anyway.
My negatives print quite well. However, I probably ‘waste’ some of the film’s potential.
In any case, my ‘clients’ are usually more enthusiastic about my photos than I am myself.
Hi Sven
So, I use a Krokus 3 with a condenser and the 2x2 corner filters from my Foma filter set.
Test strips carried out as a series of aperture settings.
I do split-grade because I hated the gradation screens even as a child (gradation-variable papers didn’t exist back then (or did I just not know about them?)).
My assumption is indeed that the other emulsion is only marginally exposed.
(But I’m sure you can measure that.)
However, this may be different when using colour enlargers, as they are supposed to work more ‘softly’.
By the way, I didn’t come up with this sock-and-handkerchief method myself.
I found it at
http://www.silberbild.info/negativ/film-eintesten/
.
My gradient is constant. ---> constantly poor.
If by ‘tweaking’ you mean: dodging, burning, pre-exposing the paper, using a warm water bath, etc. For me, that’s all part of a good print, if necessary.
In any case, I prefer high-contrast negatives; I don’t get the low-contrast ones onto paper very well.
Wolf_XL
...but you’d still need to know how long your line is – and for that, you simply need a measuring device. You can look at it any way you like – without a measuring device, you’re more or less flying by sight...
Urnes
Well, I think your problem starts earlier than that. Can you already spot the outliers on the contact sheet? If so, the problem actually lies with the exposure or the exposure metering. Calibrating the film would then only be the second step. Better negatives start with the exposure metering. Depending on the camera, you simply need experience to know when to overexpose or suffer from underexposure.
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Regards, Sven.
highscore
Hi Sven
Thank you very much for your reply.
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No, these aren’t outliers caused by incorrect exposure – I can rule that out; it’s more like a recurring theme. No matter which of my many cameras I’m using at the time, whether purely mechanical or fully electronic, with 135 or 120 film, manual exposure or in-camera exposure.
I was able to achieve correct exposure even 30 years ago, even with those tricky transparency films in backlighting. Of course, I produce rubbish too!
I still take safety shots (aperture bracketing) today when I’m not sure. And the middle shot in an aperture bracketing sequence is almost always ‘right’.
My main aim with this thread is to share the experiences of this presumably old method.
After all, even 100 years ago, our forebears were producing perfectly exposed and perfectly developed negatives without any electronics.
And if I ever fail to achieve what I subjectively consider to be good results (because I’m being too daft about it), I’ll buy a densitometer.
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Regards, Marcus
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Urnes
OK. So you think there isn’t enough contrast for your liking. In that case, it makes sense for you to test the film now. But if I remember correctly, the magenta filter (Foma Grade 5) is twice as dense as the yellow filter and therefore takes twice as long to develop anyway. That could explain why the difference is so great.
Regards, Sven.
Wolf_XL
... you'd be better off buying the Densi straight away – because whether you're a bit of a klutz or not, it'll save you a load of time... :-)
Tandemfahren
Hi highscore,
Here’s my mustard, because you’re French and your main character has an eel and all that sort of thing...
“Density 0.7 = Zone 5 = Grade 2.5” – with all due respect, that’s nonsense. The density of the negative for Zone V should be around 0.7. That has nothing to do with the gradient at first glance.
"...a black sock and a white handkerchief in daylight..." you really do need to measure the brightness of your objects, otherwise the exercise is pointless (except for the film manufacturer whose product you’re destroying there)
"I reduce the calculated time by about 10% again because slightly underexposed negatives print better" – c’est quoi ça?
In plain English: you can roughly test films without a densitometer (you don’t necessarily have to talk about measuring). However, you need to know the approximate true sensitivity of the material, and you need to know the contrast range of your test subject; otherwise, the exercise is ‘pour le chien’, as we so flippantly say here :-)
The exposure of transparency is quite different from the exposure of black-and-white negative film.
I made myself a densitometer from a Gossen Six; it cost a tenner and a few scraps of MDF offcuts, plus two grams of black wall paint.
On the other hand, you just need to set the ISO sensitivity one or two thirds of a stop lower than what’s on the box, and then extend your development time until you achieve the same exposure times for most everyday scenes when using split grading. It’s amazing how close you can get to the mark with such a quick-and-dirty approach.
Frankgröße
highscore
Thanks Sven, Wolf, Frank
I’m just going to respond to Sven and Frank for now. No offence meant, Wolf.
If the yellow Foma filter has a density that is only half that of the magenta one, that goes some way towards explaining my exposure times.
I can explain my rather nonsensical reasoning regarding the grade 2.5. My assumption is based on the fact that if I achieve the same exposure times with the split-grade filter, then I might as well expose without a filter using white light. The results should be the same. (Am I right about this now? *shudder* *shudder* *biting my nails*)
My waste of material is still within reasonable limits.
Half a roll of film, a few test strips and three sheets of paper is not much, in my view.
And I only mentioned the transparency films because the exposure latitude is much smaller.
Speaking of which, I’ve also been exposing the Foma 200 at just 23 DIN for some time now.
User Gastgeber also mentions in his review that this film doesn’t always quite reach its rated sensitivity.
Mercy. I read profiles from time to time too.
Urnes
You could have explained that without going off on a tangent about the Splitgrande. Yes, basically that’s right.
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I don’t measure it either. But my negatives were too pale for my liking too. So I started with overexposure of my films slightly (by 1/3 to 1/2 a stop) and (I develop in A 49) extending the development time a little (within the limits of the instructions). Now it works out so that I’m at grade 3 and can still use my sheet films for cyanotypes. It doesn’t matter whether you use white light or the 3rd magenta filter. Otherwise, there are at least two test strips: one for the gradient and the second for the time.
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An alternative for you might be to control the process via the developer, i.e. two-bath development.
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Regards, Sven.
jochen53
Hello,
Using a light meter (e.g. Lunasix 3, Lunasix F, Minolta Spotmeter) capable of displaying 1/3 EV, you can also measure negatives on a light box. The light box is covered with a piece of cardboard that has only a small opening for the area to be measured. 1 EV = 0.3 log density; 1/3 EV = 0.1 log density. Unexposed film = base density. You can even construct characteristic curves from test negatives. Whilst this isn’t as accurate as using a densitometer, it works well for home use.
AntiLynd
It’s not quite as accurate as using a densitometer, but it’s fine for home use.
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From my own experience, I can well understand the fun of measuring, but I do wonder whether, once the level of inaccuracy compared to a densitometer reaches a certain point, it isn’t better to stop measuring altogether and learn to assess the quality of your exposures and developments visually. On the one hand by looking at the negative as a negative, and on the other through prints. It certainly seems more educational to me.
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Especially since you can get decent densitometers for under ten euros. A pleasant side-effect of the increasing digitisation of X-ray laboratories.
piu58
>You can also measure negatives on a light table.
It also works with an enlarger without the optical system – this makes a good makeshift light table. Positioning the head horizontally makes it easier.
AndreasJung
Hello AntiLynd, hello photographers
That sounds interesting:
"Especially as you can get decent densitometers for under ten euros. A pleasant side effect of the increasing digitisation of X-ray laboratories."
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Can you give me a tip on where to get an affordable densitometer – or name the manufacturer? Everything I’ve found so far has been over €200 (goodness me... even on eBay). The spot meter solution doesn’t work well for me. So if I’m going to get one, it has to be a proper densitometer.
I’d be grateful for any tips.€
sputnik
Have a look for a Techkon RT (for reflection and transmission).
You can use it to measure both reflected and transmitted light.
They’re really handy, not those bulky things you find in labs.
I paid €50* for my RT112 years ago and the thing is absolutely accurate (I had Mr Heiland send me a test chart he’d measured himself).
The RT120 is the successor model and has (as an extra?) its own little light unit that you can clip on.
They’re sold for quite a bit more, but basically can’t do a single thing more than the RT112 – unless you don’t own a light panel.
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*OK, normally they are a tiny bit more expensive – mine was missing the battery compartment cover. ;-)
AntiLynd
Hello Andreas,
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Mine is called the Densonorm 21E, made by a manufacturer and label printer called Pehamed. The same device is also available under other brand names, for example as the IBA Duolight. I paid 13 euros for it, having bought it through a major online auction site. It replaced an X-Rite 891 I’d bought shortly before for two euros more, which I found too fiddly to use (motorised film strip feed).
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Good luck
Nils
highscore
Hi
I’ve just bought a
Bacher RT 1 Mini light table with 2 sensors
on eBay.
Is it any good?
Or should I have saved my money instead?
Regards
Highscore
janoschsimon
Have a look for a Techkon RT (for reflection and transmission).
You can use it to measure both reflected and transmitted light.
They’re really handy, not those bulky things you find in labs.
I paid €50 for my RT112 years ago and it’s absolutely spot on (I had Mr Heiland send me a test chart he’d measured himself).
The RT120 is the successor model and has (as an extra?) its own little light unit that you can clip on.
They’re sold for quite a bit more, but basically can’t do a thing more than the RT112 – unless you don’t own a light panel.
…
*OK, normally they are a tiny bit more expensive – mine was missing the battery compartment cover. ;-)
That’s exactly what I’m looking for :D I don’t have a light panel though – does it have to be a special one??
…
Best wishes, Janosch
