Ilford HP5 Plus and Rodinal with Salt – An Experiment to Minimize Grain and Improve Contrast . . .

. . . A video to accompany this test is on my YouTube Channel and you will find the link at the bottom of this post. Also, quite a long thread has grown from this experiment over at APUG.ORG and a point has been raised about the 4th set of images below (1:100 with Salt). I have added the revision below.

In an attempt to find the best method for reducing the appearance of grain to a minimum when shooting Ilford HP5 Plus and processing in Rodinal (Adox Adonal), I conducted the following experiment.

I shot 24 exposures of HP5 Plus of the same scene, with the same light. Then cut it into 4 equal lengths. Then I developed each strip using the following (controlled) methods :-

1. Straight Rodinal 1:25, 20c, 6 min’s, agitate 1st min, 10 sec’s every min’ after.

2. As above but with salt at a ratio of 30g/litre, time, temp’ and agitation kept the same in the interest of clarity.

3. Straight Rodinal 1:100, 18c, 1 hour and ambient room temp’ kept at 20c (to help maintain dev’ temp’), agitate 10 sec’ after 30 min’s.

4. As above but with salt at 30g/litre.

All with 3 sharp taps after each agitation. All were Stopped and Fixed the same way. 30 sec’s Stopper, 5 min’s Fixer, Ilford rinse method, wetting agent, dryed over night by hanging.

Then 1 frame of each was scanned on an Epson V500, with no sharpening or adjustments in-scanner or PhotoShop, just straight from the ‘can’.

First up is (my usual method) the Rodinal 1:25, 20c for 6 minutes, agitation for the 1st minute, 10 seconds every minute thereafter.

On inspection, I was quite happy with the result. As this was the first scanned strip, I had nothing to compare it against . . .

. . . next, Rodinal 1:25 + Salt (same method as above).

After scanning this one, the difference was quite a shock. I particularly like the results of this one. The salt, whilst not making much noticeable difference to the grain, has boosted the contrast throughout the image to another level.

After viewing this, I realise the standard 1:25 seems quite ‘bright’ and not as clearly detailed . . .

. . . next up, Rodinal 1:100, 18c, 1 hour, constant agitation 1st minute, 10 seconds agitation at 30 minutes.

What I find apparent here, is that there’s very little difference in contrast with the 1:25 standard and also very little difference (if any) in terms of grain size, clustering or shape. Maybe with the weaker dilution but increased time, the results are the same. Two ways to skin a cat, if you’ll pardon the expression . . .

. . . and finally, Rodinal 1:100 Salt (method as standard 1:100).

What’s apparent here is that there is a more noticeable difference with the 1:25 Salt. With the rake head for example, the contrast seems to have more balance, as though the salt was loosing it’s potency over the longer developing time (?) Also, the grain appears more structured and `busier`. I am particularly pleased with the look of this negative. (Addition. A member of APUG spotted that on the right hand 3rd of the image, there is a quite pronounced ‘lighter streak’ down the image).

. . . So there you have it. The results of the 4 tests were quite surprising for me. It would seem that none of the four methods had any real effect on grain size, clustering or sharpness. However they (to my eyes), fall into two distinct groups as far as contrast is concerned. Both the standard 1:25 and 1:100 appear to make similar images, maybe a factor of wildly different dilutions but offset by wildly different times. The same could be said of the salt solutions, however the longer period of the 1:100 Salt seems to effect the longevity of the salt itself?

So in summary and based on pixel peeping only at the moment, my money is on the 1:100 Salt.

The video for the above test . . .

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