harv
I am currently testing Fuji Neopan Acros 100 (120 format) in a 1:50 Rodinal solution.
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At the moment, I am getting the following densities:
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ZONE I II III IV V VI VII VIII
Standard 0.10 0.24 0.38 0.54 0.72 0.90 1.10 1.29
Actual 0.16 0.34 0.50 0.62 0.76 0.92 1.10 1.34
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Am I interpreting this correctly, that the highlights are fine but the shadows are too light?
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Should I now develop for a shorter time so that the density of the shadows increases (towards 0.1)?
I’m just a bit confused at the moment because the evaluation table I downloaded says I should develop for longer?!
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piu58
Zone I reads 0.16 – but according to conventional wisdom, it should be 0.1. This cannot be adjusted during development, but rather during exposure: the film can be exposed to 1/3 … 1/2 stop less light (by increasing the ISO to 120 or 144).
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The other zones also tend to be slightly too dense. With the reduced exposure, they will probably fit quite well.
To check this, you can plot a curve and apply the half-stop correction; then you’ll know for sure. However, the remaining difference is likely so small that it isn’t worth fiddling with the development process.
Renate
Hello,
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The effective speed of the film is read from the shadows. The table shows that there has been some overexposure. The speed is therefore higher than the setting on the light meter.
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The development time is read from the highlights (Zone 8). Here, the table shows me that the development was pretty much exactly N-grade. If you vary the development time, the steepness of the curve changes, whilst the shadows remain almost the same.
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You can find detailed information in Dr Otto Beyer’s book, Exposure and Development in Black-and-White Photography.
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Best regards
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Renate
harv
The exposure was at ISO 100. Developed for 11 minutes in Rodinal 1:50 at 20 degrees. Agfa Kipp.
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To abstract your advice: a new exposure with the light meter set to +1/3 to +1/2 stops should give me an N-curve for the Acros.
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Correct?
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Is this the first film I’ve read about that has a slightly higher speed than the manufacturer’s specification?
harv
I found this on Otto Beyer’s website:
http://www.fotografie-in-schwarz-weiss.de/sw-fotografie/filme-eintesten/39-film-developer.html
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The Acros has better detail in the shadows and softer highlights. That would actually match my curve.
If I meter at ISO 125, it should be fine.
Tandemfahren
Hi, er... "harv", (could you please give yourself a nickname so people can address you?)
This is the first time I’ve come across this too. And with plain old Rodinal, no less!
By the way, I always plot the curves on plain graph paper, with one zone/stop corresponding to three squares; that way you can see the third-stop increments in a very ‘analogue’ way and can also estimate the sensitivity correction (by manual extrapolation, if necessary).
What do you use to measure the densities?
harv
Tested with the Trialux. Index set to MCP 312, height set to 20x25. 6x4.5 negative stopped down to f/8.
Best regards, Stephan
Tandemfahren
Hi Stephan,
I’m not familiar with the Trialux, but just to be on the safe side, I suspect there might be a mistake in your reasoning (I was a bit surprised by the extremely precise density values).
Could it be that you didn’t measure the negative density, but rather potential positive densities?
Just checking... there was a similar case the other day.
Frank
harv
As far as I know, it measures the negative density. It gives the time, which I can then convert manually into density.
Tandemfahren
OK, I can't really say at the moment. Has the fog been lifted?
Frank
harv
Of course
harv
I’ve just measured an HP5+ film with an exposure at ISO 200. The residue is standard: 11 minutes in Rodinal, etc.
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ZONE I II III IV V VI VII VIII
Standard 0.10 0.24 0.38 0.54 0.72 0.90 1.10 1.29
Actual 0.12 0.26 0.37 0.46 0.62 0.80 0.97 1.18
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Conclusion: Speed at ISO 200 is correct. Extend development time for the highlights.
How much longer do you suggest? Starting time 11 mins. +10% +5%?
piu58
This is the first film I’ve read about that has a slightly higher speed than the manufacturer’s specification.
That’s not necessarily the case. The light meter can also be a bit off. In these small ranges, within a stop, you have to expect that.
Olivinyl
Hi Harv,
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In my experience, HP5+ in a 1:50 Rodinal solution has a sensitivity of a good 250 ISO. In your case, I’d extend the development time by 1 minute to 12 minutes.
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By measuring the densities on the enlarger’s base plate, you’ve also directly measured the deviations caused by the Callier effect of the enlarger system, which isn’t too bad.
Ideally, your prints should now land at a gradient of 2 to 2.5 on your first attempt (if your values match the target values).
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Best regards, Oliver
harv
In my run, it came out at almost exactly 200, because the shadows are almost exactly at the standard densities.
I’ll give the 12-minute exposure a go.
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I’m going on a little trip on Saturday. With Acros and HP5+ in my bag, of course. We’ll see how it turns out in the darkroom.
harv
While we're on the subject of testing: has anyone measured the Silvermax in the Silvermax developer?
Ewald
I am currently testing Fuji Neopan Acros 100 (120 format) in a 1:50 Rodinal solution.
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At the moment, I am getting the following densities:
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ZONE I II III IV V VI VII VIII
Standard 0.10 0.24 0.38 0.54 0.72 0.90 1.10 1.29
Actual 0.16 0.34 0.50 0.62 0.76 0.92 1.10 1.34
?
Am I interpreting this correctly, that the highlights are fine but the shadows are too light?
?
Should I now develop for a shorter time so that the density of the shadows increases (towards 0.1)?
I’m just a bit confused at the moment because the evaluation table I downloaded says I should develop for longer?!
?
____________________________________________________________________________________________________
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You have a gamma value of 0.5, [ (1.1 - 0.5) / 1.2 = 0.5 ]; the curve is too flat. It should be 0.7 to display all values on paper at gradient 2. Extended development (+50%, protected) makes the curve steeper. Or try Rodinal 1:25.
For Acros 100, I use Adox 49 developer, with a dilution of the stock solution to 1:1, time 13 mins, agitation, resulting in a gamma of 0.71
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Best regards,
Ewald
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harv
If I were to increase the development time by 50% to boost the gamma, the highlights wouldn’t look right anymore.
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Since the shadows are slightly above normal, wouldn’t the better solution be to reduce the exposure of the shadows a little? Or am I thinking about this the wrong way?
Renate
That’s right; if you want to match the standard curve exactly, you need to reduce the exposure of the shadows. You then adjust the value for Zone 8 using the development time.
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However, you do have a bit of artistic freedom here. If the shadows have slightly more exposure than with the standard curve, you’ll see more detail in the shadows on the paper. Depending on the film and the contrast of the subject, detail in the highlights may then be lost. The TMax 400, for example, has a wide margin for manoeuvre, whereas the TMax 100 has significantly less. I’m not very familiar with the Acros. The shape of the curve is always the decisive factor. If the curve flattens out at the top, no detail is possible in that zone.
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Best regards
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Renate
sputnik
It really should be 0.7 to display all values on paper at the 2nd gradient.
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I really don’t want to get involved in the 1001st discussion about film test discs, but when I read statements like that (and I read them VERY often), I wonder whether most testers only ever photograph standard test patterns under standard lighting conditions and whether they all have exactly the same lighting in their enlarger heads.
There is no other way to explain these rigidly fixed, universally applicable target gammas.
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Diffused light is not the same as condenser light.
A shot taken in shifting sunlight is different from one taken under a cloudy sky or in the shade.
A gradient 2 on paper X is not necessarily identical to the gradient 2 of paper Y.
Not to mention that the shape of the curve also plays a significant role in determining which average gamma is best reproduced on paper.
And ultimately, there is also personal taste to consider.
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In short: do a rough test, then make prints and see how it goes.
Once I know which gamma works best for me overall, I can of course use that as a guide when testing another combination. And if I want to compare films, naturally as well.
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But just as one person swears by Nikon and another by Canon, one sticks to their tried-and-tested 0.50 and another to 0.80.
Both – and everything in between – can be ‘right’. It just depends on the circumstances.
