Cleaning an enlarger lens with a build of "gunk"

[Todd Barlow]

Hello all, A recent darkroom purchase included several enlarging lenses that had been stored standing up on a shelf without any covering. There is a fine covering of gunk (not fingerprints or smudges, just a fine layer of dust and ?)

First I used a jumbo blower and a blast from a can off Dust Off - it removed some of the dust / gunk.
Next I used a lens pen brush and gently whisked from the centre outwards followed by the jumbo blower - again it removed some of the dust / gunk.

Looking for your best practices and experience for removing the stuck on gunk.

As always thank you in advance!

Best regards

Todd

 

[xkaes]

Most enlarging lenses are single coated. I'm assuming you can see the glass good enough to tell if there is any deterioration in the coating.

Since you have already removed any grit, the first thing I'd do is place a damp -- not soaking wet -- cloth on the glass for a minute. That should loose up most "crud". Then use some lens tissue to wipe it -- without much pressure.

Let it dry.

Then use a drop of lens cleaning solution or isopropyl alcohol on a new piece of lens tissue and wipe again.

 

[ic-racer]

Almost always a lens that "can't be cleaned" has damaged coating.

 

[RalphLambrecht]

Most enlarging lenses are single coated. I'm assuming you can see the glass good enough to tell if there is any deterioration in the coating.

Since you have already removed any grit, the first thing I'd do is place a damp -- not soaking wet -- cloth on the glass for a minute. That should loose up most "crud". Then use some lens tissue to wipe it -- without much pressure.

Let it dry.

Then use a drop of lens cleaning solution or isopropyl alcohol on a new piece of lens tissue and wipe again.

That is solid advice to me.

 

[Romanko]

I use Windex (and a lot of q-tips) to clean lenses on my old cameras. I start with covering the lens with a generous amount then blow it away with a blower, repeating several times if required. After that I proceed (gently) with q-tips.

 

[xkaes]

Windex's main ingredient is acetic acid. I can't see that helping a lens coating.

 

[Ian C]

Windex® Original glass Cleaner | SC Johnson

SC Johnson makes product ingredient information available so you can make informed choices for your family and home

whatsinsidescjohnson.com

 

[xkaes]

Thanks for the correction. Apparently only some of its glass cleaners use it. The one marked "Original" does not, but would you put ammonium hydroxide on your lens?

 

[Paul Howell]

As noted by Ian C, Windex uses Ammonium Hydroxide which is ammonia, and is not safe for coating on lens. I use lens cleaner, I still have a few old bottles of Kodak along with newer bottles of Ziess branded cleaner that I bought at the optical shop, it is designed for use on telescope and microscope lens which are coated.

 

[Yezishu]

A simple “soft” solution is kitchen detergent in purified water, or a laboratory solution of Tween 20 (Polyoxyethylene (20) sorbitan monolaurate) in deionized water, followed by wiping with alcohol or isopropanol. Clean old lenses almost always carry risks, gently wiping may itself affect the coating. It's safer to test them little by little.