Bleaching rear lens element

[Shootar401]

Can a normal black light such as the kind you find at Home Depot or Lowes be used to bleach the rear elements of an Aero-Ektar lens? Or will I need some special UV light source?

Thanks

[john wilton]

I put a compact fluorescent backlight bulb from home depot in a reflector and suspended it over a yellow 35/1.4 nikkor (first version0; after a weak the yellow was gone.

[joselsgil]

I was recommended to leave the lens in the sunlight. I have not tried it just yet as the lens and shutter are still being repaired.

[john wilton]

The heat buildup involved with prolonged exposure to ever-moving sunlight cannot be good for the lens and its mechanical parts. Blacklight recommended.

[jcoldslabs]

I was able to clear a severely browned/yellowed Aero Ektar with a CFL black light. I positioned the light directly over the rear element and put a mirror under the front element to maximize the amount of UV passing through the glass. Took a few weeks but there was hardly a trace of discoloration once I was finished.

I tried sunlight for a brief time but I wrapped the lens barrel in tin foil to keep the heat down a bit. I would say a bulb is a safer (but slower) option.

Jonathan

[John Kasaian]

Awww, the yellow glass gives it character!
For piece of mind have it checked at the nuclear medicine lab at your local hospital.

[Sevo]

Blacklight or nail polish hardening lamps are perfectly fine, indeed best for the job, as energy in the range from deep blue to near UV is what you need. If nothing else is at hand, 6500K fluorescent will do better than mid or far UV.

[lenser]

Does this also work to destroy fungus?

[Sevo]

Does this also work to destroy fungus?

No! That is, fungus doesn't thrive in well-illuminated places, and UV-A behaves quite like visible light when it comes to that - but these conditions only hinder growth, and won't kill the spores. For sterilization you'd need UV-C or at least short wavelength UV-B. Safety issues aside (both cause cancer and can blind you), I strongly doubt that UV irradiation is a appropriate solution for fungus infested lenses - glass is opaque to the shorter UV (B and C) wavelengths, so you'd have to disassemble the lens to isolate each element and irradiate it from both sides. Besides, effective wavelengths will also bleach paints and destroy rubber and plastics - effects that are generally not welcome on a lens.

[jk0592]

Wouldn't a yellow tinted lens act as a "built-in" yellow filter useful for b/w ?