C41 processing and appearance of grain

[radialMelt]

Hi all, continuing on my C41 processing at home journey and I've come up on another question that my initial searches are failing to clarify. Thanks again to the members here for sharing their knowledge.

To keep this brief, I am wondering what variables in typical C41 processing (specifically processing by hand in a Patterson tank) have the potential to increase the appearance of grain in the final negatives? E.g., over or underprocessing, underbleaching, water quality... etc

Thanks in advance!

 

[koraks]

Over- resp. underdevelopment strongly influence grain appearance (and thereby acutance) in my experience. Pulling C41 film (overexposing and under-developing) results in somewhat 'mushy' and soft images if you look closely. On the other hand, overdeveloping results in somewhat more 'crisp' images. It's a bit of a subtle difference and the terminology is debatable.

Skipping bleaching (or underbleaching, but I wouldn't recommend that, given the risk of unevenness) will also emphasize grain, and reduce saturation at the same time, due to retained silver.

Other variables won't make much of a difference for the most part, except fogging including using (very) expired film, as it scavenged images from fogged C41 film tend to come out somewhat grainy especially if scanned and then contrast-boosted in digital post.

Water quality I wouldn't worry about too much as it's mostly insignificant unless you use some kind of industrial waste water or something. Any reasonable clean tap, bottled or even demineralized water will be fine to mix up commercial developers, bleaches and fixers. Drying/water spots/marks of course are associated with calcium content in wash water, but that's another matter altogether and addressed in many threads on the forum.

To give some context to further discussion: are asking because of troubleshooting an issue, exploration of avenues for creative expression or out of general curiosity?

 

[radialMelt]

Thanks koraks. I am asking out of a combination of curiosity and troubleshooting. I've processed a bunch of Portra400 and it is scanning much grainier than I would have expected; significantly grainier than the 250D that I pushed to 400. I didn't bring this (the scanning variable) up since I understand that scanning can have a major influence on this too (and this is not the hybrid forum) and I am more acutely aware of the scanning side of things.

On the other hand, processing C41 is quite new to me and I'm still working on my routine. I thought perhaps exploring variables with respect to the development would be a good way of beginning to track down the source of the added grain. I think I may be overdeveloping some as my images are also quite contrasty. Perhaps some temperature/time experiments are in order. I suppose my developer could be over-replenished making it more "fresh" as well, thus resulting in overprocessing?

 

[koraks]

I see, thanks for clarifying. It's a tricky situation because it's hard to obtain an objective benchmark for your processing, given the lack of easy access to control strips etc. for consumers.

One thing I would suggest is to send a sample roll off to a reputable lab and keep that as a reference. By looking at overall contrast of 'typical' scenes and mask color and density, you can infer one or two things about your own processing.

I'm not experienced with replenishing C41 developer because my use is far too low volume for that. I just buy the smallest Fuji lab chemistry kits I can find, mix those to working strength using the starter and use it one shot. Even if a replenished regime may be feasible for a home user (but I think it's really challenging), at least this one-shot approach keeps me sane and confident that I get the same results every time. Over-replenishment can (will) certainly result in more contrast and more pronounced grain in your negatives. The result may be (very) significant indeed, so if you suspect this might be an issue, I'd look into the chemical management side of your process.

I'd also be hesitant to compare Vision3 250D to Portra 400. They're really different films, even if they're roughly the same speed. I wouldn't be able to say with any certainty how these films compare in terms of grain given the many differences involved in emulsion technology and processing (you mention pushing the 250D and possibly even cross-processed in C41 developer). I also believe there are no present data from the manufacturer that would allow a comparison of rms granularity of both films.

 

[radialMelt]

All good points, thanks koraks. Just to qualify my comparison of 250D, I only really made that remark because I would expect 250D @ 400iso to be significantly more grainy than Portra @ 400iso, but this is based entirely on anecdotes that regard 250D as quite grainy when pushed to 400.

I may have to reconsider replenishing my Flexicolor chemistry. It's definitely a bit of a wildcard in an already complex process.

 

[koraks]

this is based entirely on anecdotes that regard 250D as quite grainy when pushed to 400.

Hm, I can't confirm those anecdotes. I shoot a lot of 250D currently, which I overdevelop (in ECN2) to get the right contrast for RA4 printing. I find the film remarkably grain-free; 8x10" prints from 35mm show virtually no grain at all. I don't shoot a lot of Portra 400, at least not in 35mm (only 120 currently), so I'm not confident in making a comparison.

 

[radialMelt]

Hm, I can't confirm those anecdotes. I shoot a lot of 250D currently, which I overdevelop (in ECN2) to get the right contrast for RA4 printing. I find the film remarkably grain-free; 8x10" prints from 35mm show virtually no grain at all. I don't shoot a lot of Portra 400, at least not in 35mm (only 120 currently), so I'm not confident in making a comparison.

Ah! Good to know. Thank you again