What factors affect grain?

[sterioma]

I have just completed developing two rolls of Tri-X (35mm) + Rodinal. In both cases the E.I. has been 400. First time the dilution has been 1:50 (14 min), second time 1:25 (7min).

I was expecting to see some less grain in the second roll (since developing time has been decreased), but I virtually couldn't see any difference. On the other hand, I can see a great variance in graininess amongst different pictures from the same roll, but I couldn't quite figure out what to attribute the difference to.

I should add that I have assessed the grain by evaluating scans from the neg (at 3200 DPI) and trying to use the 50mm as a loupe to read the negative itself. Will bring the negatives to the lab soon to have some sample prints.


So, given a film/developer combo, which are the factors that affect the graininess of the negative?

Exposure?
Developing time?
Agitation?
...
others?


P.S. I've read that a sudden change in temperature between developer/stop-bath/fixer/wash can cause the grain to cluster, but I would exclude that since I carefully tested my temperatures throughout the process.

[clogz]

Comments on the possible factors I will leave to the more technical minded people here. However, one thing is very important: subject matter. A picture with lots of highlights and middle greys will show more graininess.
Hans

[TPPhotog]

With 35mm the difference between the grain on Rodinal 1+25 and 1+50 is very very slight. I'd also go with Hans here on subject matter.

The way I test (which is why I don't often) is shoot a whole roll of the same picture and chop up the roll to develop in different soups / dilutions.

[modafoto]

Exposure?
Developing time?
Agitation?
...
others?


The more you underexpose and overdevelop the film, the more evident the grain will become. If you rate the film (Tri-X) at ISO 400 and develop for the suiting time it will be more grainy that if you rated it 320 or 250 (and develops for the suiting time).
Also, if you agitate too much it will lead to overdevelopment and, therefore, also to more grain.
Last I will comment on the use of Rodinal with Tri-X. This combo is GREAT, but it is a good thing to experiment with rating the film 250-320 instead of the 400 it says on the box. The reason is, that Rodinal decreases the speed a bit.

Please correct me if I'm wrong, but this what I have been told and experienced.

[sparx]

I would have thought pushing the film would have more effect than different dev dilutions. Don't dilutions affect contrast more than grain?

[sparx]

Thankyou Morten for beating me to it :p

[TPPhotog]

Yep Pushing the film boosts the grain beautifully if that's what your after. But as both films where shot at the same speed it shouldn't be a factor here for the comparison. On some frames your errrrm exposure might be a bit off but I didn't want to mention that (where's the blushing emoticon on here?).

[sterioma]

On some frames your errrrm exposure might be a bit off but I didn't want to mention that (where's the blushing emoticon on here?).

No need to blush :)

I am here to learn and therefore if also an exposure problem is (perhaps) to be blamed, I need to know about it! :)

Tonight I will try to post some sample from the scans, so that maybe the diffrerence in grain is easier to spot for you guys. I have found that resizing the scan removes most of the grain (and sharpness for that matter), so maybe I will post some small crop at 100%.

[ThomHarrop]

Another factor in grain is wet time. Overly long fixing or washing times can also cause migration of silver grains and add to clumping (which is what we see as excessive grain).

[Flotsam]

Years ago, I worked as a B&W printer in a Lab over in White Plains. One day the guy that processes the B&W film came into the printing room with a roll that was about as reticulated as any that I've ever seen. It was was first thing in the AM and in his pre-coffee condition, apparently didn't notice that his wash water was coming in at 150 degrees F. The effect was quite interesting,although not exactly what he client was going for. We gave him back his roll along with an admonishment not to leave his camera in his glove compartment on a sunny Summer day ;)

[Nicole]

The more you underexpose and overdevelop the film, the more evident the grain will become. If you rate the film (Tri-X) at ISO 400 and develop for the suiting time it will be more grainy that if you rated it 320 or 250 (and develops for the suiting time).
Also, if you agitate too much it will lead to overdevelopment and, therefore, also to more grain.
Last I will comment on the use of Rodinal with Tri-X. This combo is GREAT, but it is a good thing to experiment with rating the film 250-320 instead of the 400 it says on the box. The reason is, that Rodinal decreases the speed a bit.
Please correct me if I'm wrong, but this what I have been told and experienced.

Hi M, please help me understand the different effects again.
If I use Tri-X 400 and expose at 320, do I ask the lab to process at 320 or at 400? In doing either, what effects can I expect?
Thanks M!

[ann]

shooting at 320 should give you more shadow detail and i wouldn't tell the lab anything, this dfifference is very small, however if they are using kodak's numbers don't be surprised if they are over deveoped, it is a common issue at least in this area fir the labs to overdevelop ,which does increase the grain

[sterioma]

I am finally home so I can post a couple of samples from the same roll (Tri-X at E.I. 400 and Rodinal 1:25 for 7 minutes). I have attached both the complete picture resized (and smoothed by the algorithm) and the detail from the scan at 3200 DPI.

To me the difference in graininess is quite different. What do you guys think?

Stefano

[modafoto]

Hi M, please help me understand the different effects again.
If I use Tri-X 400 and expose at 320, do I ask the lab to process at 320 or at 400? In doing either, what effects can I expect?
Thanks M!

Don't tell them anything. It is just a third of a stop overexposure which is OK (if not better) with negative films (gives you more "information" on the film = shadows detail).
Try doing a roll with exposures at 200, 250, 320 and 400, and write which frames have been exposed in which way. Then you can evaluate the negatives and see what kind of rating you like (at the given development the lab offers).

Don't you have the possibilty of developing yourself. I will give total control and you'll save some money.

Greetings Morten

[Helen B]

Please don't read the things you already know, or the bits where I'm talking rubbish.

I think that it's quite difficult to compare graininess without controlling lots of things - including what you use to make the comparison. I guess that it's OK to use a scanner for comparison, if it is the scanner that will be used for final output. A lot will depend on the scanner - and particularly the interaction between the film granularity and the scanner resolution. Grain aliasing and all that.

Contrast affects the appearance of grain, as does density. Therefore if you don't develop the two films to the same contrast, and compare areas of the same density (preferably of the same subject) then it's difficult to be objective. You may not wish to be objective, of course, and that's perfectly valid as well.

Some extracts from the Communist Party (Marxist-Leninist) Manifesto:

Overexposure increases graininess and decreases sharpness with conventional monochrome negative film, if the development time stays the same. Hence the saying: 'Expose just enough.'

Overexposure decreases graininess with chomogenic B&W and colour negative film if the development time stays the same.

Increasing developer dilution slightly increases graininess and sharpness (a very general, and dangerous, er, generalisation). The effect varies between developers, but in many cases the change is caused by the change in sulphite concentration: from a high sulphite environment (say 80 to 100 g/litre) to a low sulphite one (say less than 30 g/litre).

Best,
Helen

[modafoto]

Overexposure increases graininess and decreases sharpness with conventional monochrome negative film, if the development time stays the same. Hence the saying: 'Expose just enough.'

Overexposure decreases graininess with chomogenic B&W and colour negative film if the development time stays the same.

Ok? I thought it was the rule for all of them...

Thanks for expanding my knowledge!

[TPPhotog]

I am finally home so I can post a couple of samples from the same roll (Tri-X at E.I. 400 and Rodinal 1:25 for 7 minutes). I have attached both the complete picture resized (and smoothed by the algorithm) and the detail from the scan at 3200 DPI.

To me the difference in graininess is quite different. What do you guys think?

Stefano
Mmmmmm Stefano sorry not helping me I'm affraid :( I'd suggest you shoot a whole roll of one picture with no other variations. Cut a few frames off at a time (in darkness of course) and try souping each length in different dilutions. That way you will be able to compare the results without any other distractions.

[sterioma]

Helen, thanks for your comments.


I guess that it's OK to use a scanner for comparison, if it is the scanner that will be used for final output. A lot will depend on the scanner - and particularly the interaction between the film granularity and the scanner resolution. Grain aliasing and all that.

I haven't got the space and money and the time to learn to do my own prints right now, hopefully this will be an option next year. In the mean time, as I mentioned before, I am using the scanner to evaluate the negatives I am producing (I have just developed 3 rolls so far!). I guess I will need to invest in a loupe. As far as the prints are concerned, I am evaluating trying both to have the prints from the scan and from the negatives (by a lab), and decide what I like better (and what's cheaper).




Contrast affects the appearance of grain, as does density. Therefore if you don't develop the two films to the same contrast, and compare areas of the same density (preferably of the same subject) then it's difficult to be objective. [...]

Actually the samples I have posted are from the same roll. I was experiencing a different grain across the different frames, so that's the reason of my post.

[Helen B]

Oh, I told you not to read the bits where I was talking rubbish...

I did realise that they were from the same roll - but perhaps didn't make the differences between specifics and generalities clear enough. This is the root cause of all human conflict, I believe. Were the two frames scanned with exactly the same settings? (Is the software doing something behind your back, out of your control?) How does the local contrast differ in the two examples? How does the density differ? These are the kind of questions to ask yourself, I guess.

The local contrast, density change and overall density will affect, to some degree or another, the exact way in which the developer works grain-by-grain. The more agitation, the less the effect, in general.

I've got nothing against scanners (and you don't need to justify using one) but some of them do behave oddly when they are dealing with opaque grains/grain clumps when the grain 'size' is in the same ball-park as the scanner resolution. Just another influencing factor.

Best,
Helen

[Woolliscroft]

I've got nothing against scanners (and you don't need to justify using one) but some of them do behave oddly when they are dealing with opaque grains/grain clumps when the grain 'size' is in the same ball-park as the scanner resolution. Just another influencing factor

That's true, especially if you have anti dust/scratch software running as it can knock out small gaps between grains by interpreting them as dust spots. However, is there really that much difference in the grain between the shots you posted? One shows a lot of detail, the other large areas of mid tone. Grain always tends to be more visible in the latter than the former even though objectively the same size. I never did much like Tri-X because of the grain, although I am having to use it now since Delta 400 vanished in 220. If you don't like it but need the speed you can always use Delta or Tmax.

Incidentally, I notice that the Pro medium format version of Tri-X is rated at 320. Is it the same emulsion or is it really a bit slower?

David.