Adox CMS20 – Fast Becoming a Favourite Slow Film

It’s always fun to try a new film – especially if it’s one of the more exotic ones.

This post is a mini test of 35mm Adox CMS20 black and white film, which claims to be ‘The sharpest, most fine-grained and highest resolving image recording system in the world‘ with an equivalent of 500Mp of detail on a 35mm negative. It’s original purpose was as an ultra high resolution and high contrast document film, but if developed properly it can yield a full range of mid-tones.

So, I had to give it a try.

Zuiko 50mm f1.4 at maximum aperture

Sample from the top left plus a few dust spots

As you’d expect it’s slow – 12 or 20 ISO, so your first problem might be finding a camera with a slow enough film speed setting. The Olympus OM2 goes down to 12 so that’s what’s been used here, along with my sharpest lens, a Zuiko 28mm f2 shooting at f5.6 or f8 – and a few from the Zuiko 50mm f1.4.

Zuiko 50mm f1.4 stopped down to f5.6

Adox recommends a specific developer, ADOTECH II CMS which is quite pricey by comparison with ID11 or Rodinal, but as I wanted to do something approaching a proper test I used that. The processing is different to most films – the developer smells strongly of something like acetone, fixing takes a very short 45 seconds and is followed by a short wash time of 5 minutes. Caffenol, Rodinal and HC110 can all be used too.

Zuiko 28mm f2 at f8. This is Knowlton Church, now a ruin, in the centre of a neolithic earth circle (a ’causewayed enclosure’) which is 4000 or so years old. A spooky location for a film test. There’s loads on Google if you’re interested.

As a general impression it looks a little like Ilford PAN F, and the slow speeds allow some nice shallow depth of field effects with a fast lens. It shares PAN F’s tendency towards high contrast darker images which I quite like.

28mm f2 at f8 – White Mill Bridge.

The ultimate question though is – where’s the grain? Here are some enlargements from a scan from a Plustek 7500i set at 18 by 12.6 inches at 350 dpi which is close to it’s maximum physical resolution.

Here’s a shot of White Mill –  a National Trust property on the River Stour. No spotting or dust removal just straight from the scan.

28mm – White Mill

And here’s a couple of small samples from the shot  :-

The dovecotes in the centre of the picture. The brickwork is still sharp.

Enlargement from the top left of the shot

No grain at all, except a slight speckling in the sky which is just discernible. It’s easily out-resolving my best lens and scanner and showing no grain – something I can pick up with PAN F. These are only scans – Adox claim it can be printed grain free up to 2.5m horizontally from a 35mm negative and I’ve no reason to disbelieve them after this mini test.

The only downside of this film is that there’s no grain to hide small dust or spots, so for a large print it will take a lot of cloning/spotting.

If you haven’t already, give a few rolls a try – if nothing else shooting at 12 ISO is an experience! It’s available in 120 and as sheet film too – in 5×4 with a top lens, the resolution must be astonishing.

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