Difference between light bulbs; incandescent vs LED.


Site Donor 2023
Jan 9, 2009
New England
Can anyone tell which is the LED and which is incandescent? For some it will be obvious, but practically speaking, can you tell the difference?

The LEDs are several years old. They replaced the incandescent bulbs, which I still use in the winter time to use them up (I have all electric heat). I have the fans on low reverse to circulate the heat.

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I would guess the one with the printed text is a glass incandescent.

Led will be a plastic bulb with a white base. They can also flicker when a heavy load like the ac or drier turns on.
I have had several of those filament led bulbs crap out on me. Most of my CFLs lasted longer than the filament led. I still haven’t replaced all the CFLs in my house yet. They keep going.

The new led bulbs are nice since they got rid of the shadow that the base made. They have come a long way from the corn cobs and even the L prize design.
LED's are said to be BAD for eye health but save power. so you might need the $$$ save for your eye health as supplements as well as foods containing critical nutrients can keep eyes healthier. i take a LOT of supplements + except for close work mt 74 YO eyes work great + am amazed what i can read even without glasses!! i shy away from LED's BUT incandescent are harder to find, but i DO!!
The A19 is a bulb size. If all the bulbs are A19 then I can’t use that to discriminate. The incandescent will be the one with the most uniform amount of light emitted in every direction, including back at the base. LEDs won’t try to emit much light back at the base, as it’s often absorbed into the luminaire.
if I had a prism to split the light into spectrum bars it’d be easy.
Can't tell from that photo, since it is not exposed for the bulbs, so the differences are blown out.
I'm a DP, so it's part of my job to see things like that - If I would be there, I could tell.
They are always too much on the green side, compared to a incandescent.

In a way isn’t that actually a good thing? You have usable light and a warning that the bulb need to be changed. The alternative is darkness a millisecond after there was light. No warning.
I’ve seen B/O ones illuminating either the freeway or a billboard on the 4:30am drive to work. 30Hz full-on to full-off. I strongly prefer how other bulbs fail!