Ignoring the warning ⚠️

[Plasmid]

I recently purchased some replacement bulbs, oddly enough there is a warning on the box that has me concerned ( the don't look at it part). They were advertised as Microscope replacement bulbs, should I be worried?
20w 6v G4

[PeteM]

Part of a full employment plan for lawyers and graphic designers?

Seems they forgot an icon for not getting oil from fingers on the quartz envelope (thus resulting in shorter life). Got to keep the OEM busy as well?

More seriously, they do get hot and could possibly cause a fire. They are bright -- and without passing through a dozen lenses en route to our eyes might be a source of damage to someone inclined to stare at the bare bulb as some sort of hourly meditation.

[Plasmid]

I was seriously considering purchasing a dichroic UV filter just so I could use them.

Thank you PeteM,

[deBult]

Pete,

As you have only one pair of eyes, the filter is a good precaution ...

[Greg Howald]

Halogen light is mostly in the red wave length and usually has little uv. It can be extremely bright. A filter of light blue color will usually soften the light. Most scopes using halogen lighting have such a filter built into the illuminator lensing system.
Greg

[Greg Howald]

I have a scope with kohler halogen lighting. The light seemed insufficient until I had centered the light path. Then it blew me away at low magnification and gave excellent imaging at 100x without oil. I placed an extra diffuser in the filter holder so I could swing it in and out of position. This helped greatly..
Greg

[PeteM]

I might add, with respect to UV, that some of the LED bulbs do put out significant amounts in that range. Concerned, I bought some affordable UV camera filters from China. While they were clearly marked for UV, upon inspection with a spectrometer they turned out to be pretty much clear glass. Trust but verify and all . . .

Clear polycarbonate plastic, of the sort often used for high index eyeglasses, safety eyeglasses, and welder's helmet protective inserts (cheapest reliable source) does do a good job of filtering UV.

[MichaelG.]

This might be the relevant datasheet : https://www.osram.com/appsj/pdc/pdf.do? ... MP_1006707

But this one [for a 12v version] usefully includes a spectrum : https://docs.rs-online.com/be10/A700000006468680.pdf

MichaelG.

[lightshape]

Without an IR/heat filter in the light path, my critters won't survive 60 seconds with some halogen 25 watt lamps.
Stefan

[LouiseScot]

I suppose the rated colour temperature of the bulb (if that's on the box?) will give an indication of how much blue light is in the continuous spectrum. I think the blue filters reduce the infra-red (heat) and the amount of red light.
One can always convert to LED - does anyone have a circuit/details for making a variable LED light source?

Louise

[PeteM]

Without an IR/heat filter in the light path, my critters won't survive 60 seconds with some halogen 25 watt lamps.
Stefan

Far as I know, most of the better scope makers include an IR filter; typically between the bulb and where the light path enters the back of the microscope. I've had to replace some - they can get cracked by the thermal shock despite their having a low coefficient of thermal expansion.

[EYE C U]

pretty sure i damaged my eye with uv. a was looking at felt material ..now i have a circle of grey (like dead pixels of a sensor) in the center of my vision that looks like the material i was looking at..couple months now and no change

[Plasmid]

Without an IR/heat filter in the light path, my critters won't survive 60 seconds with some halogen 25 watt lamps.
Stefan

Far as I know, most of the better scope makers include an IR filter; typically between the bulb and where the light path enters the back of the microscope. I've had to replace some - they can get cracked by the thermal shock despite their having a low coefficient of thermal expansion.

How can one tell if said filters are included? Example Reichert's, Nikon's etc? Wouldn't that be normally found in the diffuser and or blue filter and or eyepieces?
And is there a stand alone filter that can be placed on top of the Illuminator ?

[PeteM]

With respect to IR - my experience is that most of the better makers include a clear IR filter fairly close to the halogen lamp source. If you see a clear glass element, with no magnification, it's likely that is an IR filter.

It could be that IR filtration glass is also sand blasted to make diffusers in some scopes? I don't have any direct knowledge.

I suppose the sure way to tell for your own scope would be to buy a spectrometer. Ones that will go reasonably far into both the UV and IR ranges can now be had for $300-400. Possibly an excuse to buy another toy?

More simply, one can measure the temperature at the slide with something like a cheap non-contact thermometer. Depending upon what you're viewing, heat may or may not be a big deal. Even with protists, one can often replenish the water supply under a cover slip.