Lens cleaning question: caked on dust

[LewisDowney]

Hello,

I am embarrassed to admit that the single best piece of glass I own has endured a terribly unfortunate circumstance. My enlarging lens, a Schneider APO-Componon HM 4/150, sat in open air for 10 years without the lens cap for the rear element.

As a result, the rear lens element has a wealth of dust on it. I imagine the dust to be slightly caked onto the lens surface by changes in humidity.

Embarrassing as this is, I am delighted to be returning to the darkroom. Would anyone care to suggest the best way for me to clean this lens? Or is this a clear case of sending it off to a pro.

Thanks in advance,

Lewis

ps. In the pictures below, the crud immediately around the outside of the lens is supposed to be there. It is foam and does not need to be removed. I assembled a makeshift lens alignment device, modeled after a commercial product sold by Calumet or Zone VI or somebody. The foam belongs to that mechanism and should not be causing any problems. Thanks again!

pps. I cleaned the back of the lens board and added a third pic of the lens. The first view from an angle makes the lens look a bit worse of than it really is.

[BarryS]

1) Blow off the loose dust with a rocket blower or similar.

2) With a high quality lens cleaning fluid, dampen (not drench) some lens tissue and lightly swab in a circular motion starting at the center. Frequently change the tissue and use only light rubbing motions. Work your way out to the periphery of the lens element. Multiple light applications will be better than rubbing too hard. Good luck.

[walter23]

1) Blow off the loose dust with a rocket blower or similar.

2) With a high quality lens cleaning fluid, dampen (not drench) some lens tissue and lightly swab in a circular motion starting at the center. Frequently change the tissue and use only light rubbing motions. Work your way out to the periphery of the lens element. Multiple light applications will be better than rubbing too hard. Good luck.

After some serious blowing, you might want to dab it at first to try to remove the dust without rubbing.

[LewisDowney]

Update! I called Opticlean but landed in voice mail and opted not to leave a message. Then I called Schneider (the east coast office in the U.S.) and after some helpful discussion was advised to call John Sioringas of the west coast office for a more definitive answer to my questions.

My questions were pretty much an effort to find out if the barrel of my lens is made of metal or polycarbonate -- with the intention of coughing up the $100 for the opticlean solution depending on the answer. Sioringus felt that is was highly likely that the barrel is made of something other than polycarbonate.

Nevertheless, he encouraged me to clean the lens in the following manner. Dilute 1 part Windex with 1 part water. Get a bunch of Q-tips then carefully wet a swab with the diluted windex and dab gently at the center of the lens, changing swabs often.

That is exactly what I did. I worked from the center of the lens outward using a number of q-tips, one at a time, in a dabbing motion. I disposed of Q-tips before they showed any schmutz. After the lens seemed clean, I cleaned it again using lens cleaning fluid and lens cleaning tissue. The entire process only took a few minutes and I incurred no expense except a half-ounce of Windex and several Q-tips. John Sioringus indicated that Windex has a weak ammonia in it and that actually is a benefit as long as the Windex is diluted.

The results seem to be fine; although I have not looked at the lens under magnification, nor have I actually started to print yet. The lens surface appears perfect from every angle I have viewed it from. If time and early onset dementia allow, I will post a photograph of the clean lens.

I imagine the Opticlean would have worked perfectly, but I went another route.

My thanks to everyone who responded or offered advice. For the time being I am cleaning floating lid tanks and mixing chemicals. Film testing is imminent.

Lewis

[Gordon Moat]

When I got my Holmes, Booth & Haydens lens, it had quite a layer of protective dust on it. Ended up using a blower brush first, which really didn't remove much of anything. Then I took Kodak Lens Cleaner, and let it slosh around on the surface. That got even more off. At that point, it was possible to disassemble the lens, and do a more proper cleaning. The result was perfectly clear optical elements . . . seems the dust really did protect the lens, for however many years it sat unused (lens dates from 1854). So take your time with it, and don't be sparse with the lens cleaner.

Ciao!

Gordon Moat Photography

[LewisDowney]

Hey thanks Barry and Gordon.

If it helps, we have a small ultrasonic cleaner. I could remove the back portion of the lens and hold it above the bottom of the ultrasonic cleaner for a few minutes. I am a little worried that the liquid will penetrate to the interior of the lens though. The liquid is water with a mild detergent, not a solvent.

For that matter, I could replace the mild detergent with plain water. Even with plain water, my concern is that the ultrasonic cleaner might cause some of the fluid to work its way to the interior of the lens.

Thoughts? I am not prone toward disassembling the lens down to the glass elements.

-Lewis

[resummerfield]

.....we have a small ultrasonic cleaner. I could remove the back portion of the lens and hold it above the bottom of the ultrasonic cleaner for a few minutes. I am a little worried that the liquid will penetrate to the interior of the lens though. The liquid is water with a mild detergent, not a solvent......

I would NOT use an ultrasonic cleaner on a glass element. With the elements in the lens, use regular lens cleaner, or just plain distilled water. If you remove the lens, use a mild dish washing detergent under running warm water, then rinse with distilled water. Use a very soft cloth, or better, a micro-fiber cloth designed for lens cleaning.

[Gordon Moat]

If you don't want to disassemble the lens, then I would suggest just using lens cleaner. The only ultrasonic cleaner I am familiar with is one I use to use with Rapidograph pens, but the solvent was something I don't think would work well on lenses. Lens cleaner fluid would be a much safer choice.

Ciao!

Gordon Moat Photography

[LewisDowney]

Yeah, maybe it is a perfectly ordinary cleaning situation; albeit one that requires extra delicacy.

[lenser]

Sounds like good advice so far, but you might want to try 'lifting' the dirt off with the first several applications of lens cleaner and tissues rather than wiping or swirling. Those activities could result in scouring into the coating or glass if there is even the thinnest grit in the dust.

By moistening the tissue and dabbing and lifting over many applications, you can get the really bad stuff off and then, when it is almost totally clean, use a camel hair brush to get rid of the final bits and then go with the moistened lens tissue in a normal wiping final clean.

Good luck.

Tim