Rodinal - dilution and grain?

Many people seem to dilute Rodinal at 1:50 or 1:100 but I seem to

remember someone saying (Barry Thornton perhaps) that increased

dilution and developing times has the effect of increasing grain.

Have I remembered incorrectly? What are your thoughts and

experiences? I am most curious regarding Rodinal with FP4+ and APX

100 but also, what would be a good dilution to control the grain in

Tri-X?

 

Steve

IIRC, developer dilution, all other things being equal, will increase grain size because of the increased time in the soup. With many developers, increased dilution will also show an increase in apparent sharpness. Many people think the increase in sharpness makes up for the increase in graininess. Clearly, YMMV.

I use the 1:25 dilution with Rodinal and don't see any grain problems with Tmax 100 or Agfa 25. You probably ought to shoot some test rolls with whatever film you are using and try both dilutions. Let us know the results.

AFAIK, Rodinal's grain size <i>decreases</i> in greater dilutions. There is some evidence this is due to the activator which is used in that particular developer--KOH. Personally I would <i>never</i> use it at the 1:25 dilution, 1:50 is the standard dilution and dilutions over that are not uncommon. At 1:50 developing times are not too long (10mins or so) in standard tanks. 1:25 produces golf ball grain.

I've found just the opposite of what Nicholas claims -- maybe I'm doin' something wrong but I'd figure after several hundred rolls of APX / dilute Rodinal...<P>Dilute Rodinal developer and the increased time the developer takes to work causes film grain to swell -- that means an increase in grain size.<P>There is also an increase in accutancy and shadow detail. That <i>may</i> explain why grain appears smaller to Nicholas (or larger to me?) -- I not at all sure of that though.<P>There has been hundreds of threads concerning Rodinal and/or dilute developers. I suggest you search the archives for more information.

I just made a small (5x7) print from FP4+ (rated at 125) using a 1:25 dilution @ 19 degrees C for 8 min. Now, I realize that 5x7 is not large but the grain is not obvious at all so I wouldn't expect it to become golf ball size on a larger print. I will do this to see what its like. I'll also try other dilutions.

Thanks for the advice.

Steve

My limited experience with Rodinal agrees with Nicholas Twist. I like 1+50 over 1+25 any day of the week. finer grain, better sharpness, nicer tonality - IMO. I would think twice about using anything faster in 35mm than 125 ISO nominally rated film (APX100, FP4, etc) espcially tri-x or HP5, those in rodinal always end up looking very grainy espc in 8x10s. Although HP5 rated at 200 deved in 1+50 rodinal is barely acceptable grain for my tastes in 35mm. For 120 film its a different kettle of fish, rodinal makes wicked negs in that format!

 

Try it all out, and settle on what you like :)

Grain has more to do with the inherent qualities of the film than any developer used to process it. Tri-X or HP5+ processed in Microdol-X will never be as fine grained as Plus-X or FP4+ developed in Rodinal. That's just the way it is. If grain control is your goal, then perhaps you should consider using another developer. D-76 or ID-11 will produce a nice balance between grain and sharpness for Tri-X. Use it straight for finer grain or dilute it 1+1 for a little more apparent grain and increased acutance. You'll get similar results with XTOL with the added bonus of about 1/3 stop of increased shadow speed at higher dilutions. I can't say with any certaintly what the differences in grain would be between using Rodinal at 1+25 vs. 1+50. My limited experience with several films in Rodinal at 1+25 vs. 1+50 has shown, and this agrees with a lot of popular wisdom, that Rodinal behaves more like a compensating developer at higher dilutions.

Rodinal is not like most devs. It is a low sulfite/high pH dev.

 

High pH leads to very quick emulsion swelling, which leads to grain crumpling. Low sulfite means there is no solvent effect on the halides, so grain is very sharp, not masked by many filaments.

 

When one dillutes it, pH goes down and also emulsion swelling and grain.

 

Other devs, D-76 for instance, are low pH, high sulfite.

 

The low pH makes swelling to happen much slowlier, and high sulfite means grain will be masked (and sharpness will be lowered).

 

When one dillutes D-76, the film stays longer in the dev, there is more time for the emulsion to swell, the reduced sulfite content masks less the grain, so the overall effect is of a grainier neg, but sharper.

 

So, what applies to one family (low sulfite, high pH - Rodinal, FX-1) does not applies to the other (high sulfite, low pH - D-76 and most others).

 

I hope the above is clear.

FWIW, I use Rodinal 1:100 for Tri-X sheets (in a homemade BTZS tube, 20 C* for 20 minutes) and find that they are very sharp. Of course, the grain is present, but on that size negative, enlargements are still good. I would not try this on 35 mm b/w films, tho. I also would not -- and do not -- use Rodinal on "T" grain films such as Kodak TMX/TMY/TMZ or Ilford Delta 100/400/3200. For those, I use Ilford DDX.

Don't confuse grain size with acutance - grain size is the actual average diameter of the grain, while acutance refers to the sharpness, ie. how distinct the edge of the grain is. Less diluted Rodinal (eg. 1+25) tends to have higher acutance than mroe dilute (eg. 1+100.) A higher acutance leads to two aesthetic impressions: the grain appears more prominent, ie. the image looks more grainy, but the image appears sharper as the grain is in tight spots, not fuzzy blobs. Whether you like high acutance or not is up to you. Personally, I like acutance, but I vary this depending on subject matter and film format.

 

In terms of actual grain size, I've become more and more convinced that this is mostly a property of the film and only to a smaller degree affected by the developer, as acutance easily gets mized with grain size. Of course some developers work much better with some films, but a 400 speed film doesn't become Tech Pan no matter what you soup it up in...

Grain is a bit complex. For instance, what one calls print grains are actually voids...

 

For anyone interested in the matter, take a look at:

 

http://www.imx.nl/

 

Under techniques, click on film basics and B&W film. Or read the whole topic, very interesting.

I've never had the experience of grain getting larger with higher dilutions of Rodinal. Just the opposite. Higher dilutions look to me to produce smaller grain, for whatever reasons. It works well with Tri-X too, up to about 9x enlargement. My one try with HP5 was not so good though. Much over a 5x7 (with 35mm) and it seemed to fall apart.

 

Dean<div></div>

I personaly found that FP4 in rodinal at 25:1 had larger more mushy grain and less sharpness than FP4 in rodinal at 50:1 which seemed have finer tigher and less mush grain. I always assumed that rodinal is highly alkaline at 25:1 and this high PH level lead to grain clumping and the mushy look I experience with FP4 at 25:1 but the 50:1 solution is probably has a lower PH and so the grain does not clump so much. I shot a lot of APX 100 and developed in rodinal 25:1 and personaly I found it to be OK much better than the FP4 at 25:1 but I have personaly found both films to be more preferable in D76. I develop FP4 in D76 1:1 and APX100 in D76 1:0 and I am happy with how they come out. As for TriX I have developed a few rolls in rodinal 50:1 the sharpness is great but depending upon the subject matter it can look a little grainy for my tastes for TriX and HP5 I like HC110.

 

Regards....