Rodinal 1+25 vs 1+50


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>>Azriel:Rodinal, it's old as dirt but people still use it. This awesome little one shot developer has been around since the 1890's, and is still considered a top choice for black-and-white photography, because it is super easy to use.

The version I have is called Blazinal. It's chemically identical, but has a much better name.

Hi everyone, Azriel Knight here, and today I want to look at the dilution differences of Rodinal.

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If you've seen my previous experiments, I make a strong effort to only change a single variable, while ensuring everything else is the same.

In this case, I need two identical, or nearly identical frames from the same strip developed separatly.

In order to accomplish that, I set out for a generic photo that had both highlights and shadows, and something that people in general can recognize: a sunset.

I considered doing it indoors in a more controlled environment with strobes to ensure, ah, precise exposure, and I may consider that in the future, but I needed something universally recognizable, and a little more interesting than a lineup of random 80's toys.

I used a handheld light meter to gauge a good average and also compared that with my camera's meter, a Nikon FE, and both gave the same result. I chose to overexpose slightly, I got a reading of 1/160, and went 1/125. In hindsight, I suppose I could've, uh, used exposure compensation, but it worked out fine and we're more concerned about how they compare to each other, anyway.

I shot all my frames quickly, both photos that you'll see in today's example were shot within a minute of each other. In the future I may use a motor drive to narrow that gap.

In the darkroom, I separated the two strips into their own tanks and developed each one as normal, except I did at 1+25, and the other at 1+50, of course.

Why do this at all? Well, I think the most important formula here is this: will the extra time it takes to develop a 1+50 be worth it in terms of savings, and can I live with, or do I like the results.

One 500mL bottle could develop 43 rolls of 35mm film, or it could do 86. To develop 43 rolls of Tri-X, not including stop and fix at 1+25, is a total of 5 hours and 1 minute. To develop 43 rolls with the same at 1+50 is 9 hours and 19 minutes, but you'll still have half the bottle left. Before I show you the scans, there are a few things to keep in mind here, like exposure differences shot to shot due to the slight variation of shutter speed, and the setting sun, the slight curve differences of the film when being scanned, as well as the crop of each frame, not to mention any slight variation in the exposure of the scanner itself. Lastly, the temperature difference in the developer: I did try and keep it at 68 Fahrenheit exactly, but there's probably a half to 1 degree variation. I should also mention that different film will yield different results.

I'm using Tri-X because it's an old, readily available, and popular black-and-white film. It's a forgiving film, so while you get the same kind of results with different films, the degree of severity may be more dramatic. Okay, here are the scans I'll leave them up unlabeled for a few seconds each.

These scans have no editing in them whatsoever, but you will still have to consider YouTube's rendering and your monitor.


Alright, here's the 1+50 and 1+25. Just eyeballing it even as a negative, it seemed obvious to me that the 1+50 lacked the punchy highlights, but arguably about the same amount of mid-tones to shadows.

Let's have a look at the histograms.


You can say there's more contrast to simplify things, but how much contrast from the darkest to lightest areas is just not consistent across, it varies. It would be more accurate to say it has more contrast in the midst of highlights, while retaining shadow detail. The last thing I want to mention here is sharpness.

If you look closely at this tower here, called the Bow Tower, you can see the 50 is sharper, it's not by leaps and bounds, but the pattern in the building is more noticeable here.

Scanner can give some great info, but I don't think it's without its drawbacks. I realized the only was I was gonna see the whole picture was to come back here into the darkroom.

I made a series of test strips and here's the breakdown of that. My goal here was to see how the image renders on paper and how the grain looks in the highlights.

I made four strips, two from each negative. Using my enlarger, I set out to make a small section of the biggest enlargement. To do this I set my enlarger all the way up to the top, in this case 22in long is as big as I can get with my current setup. My test strips were five by seven glossy RC sheets, I did one strip with 2 1/2 contrast filter at 10 second intervals, and the other with a number 5 filter at 40 second intervals.

Doing this for both negatives, and developing in Dektol. I did the number 2 1/2 strips just to see what a generic exposure looked like, some of this is just about personal taste, but from the 1+50 strip, I would have gone with a 20 or 30 second exposure and the 1+25, I would likely do a 40 to 50 second exposure.

I thought if I did a long with a number 5 contrast filter, I could bring out as much grain as possible in the highlights, thus being able to see how it was effected.

I would expose the hell out of the highlights and the tiny black grains would poke through, so to speak. Looking at the two strips, and putting the 120 second exposure from the 1+25 and the 80 second exposure from the 1+50, the 1+50 looks like it has a little more grain.

I can't be sure though, I don't have an exact comparison. My task for next time will be to make sure my strips compensate better,

I need to see it for myself to be 100 percent. Alright! Now that I have what would be the analog version of pixel peep, uh, grain gawk, now that I have finished grain grain gawking at everything, here are some of my thoughts. 1+50 is a good dilution if you want to, A, stretch the use of your developer B, retain higher sharpness, and/or C, lower the contrast of the negative. Use a 1+25 if you want to, A, save time developing, and/or B, increase contrast of the image.

I am sure there are other differences and benefits that I missed here, and I would love to read them in the comments below, but my knee-jerk reaction is that 1+50 has slightly more upsides for me, it's a flatter negative so you can control your contrast more, it costs half as much and it's sharper.

I think at the very least it's a reminder of how nuanced film photography is, and even if you got your choices locked down, i.e. your camera, lens, film, and ISO, you still have other ways to control your final image. Just try not to get lost in the details, and remember the the point is to get out there and shoot.

Well that's all for now, and I hope you enjoyed this experiment.

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