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LED shadow vs incandescent lighting

12/28/2021 11:43 AM

Hello Everyone - (Not sure if this is the correct Forum) I've got a question that I've researched but so far have been unable to get a definitive answer to.

It 'seems' LED lighting creates darker shadows compared to incandescent lighting. I tested this in my shop by installing various temp LED lights over my shelving and workbenches. The shadows were dark enough to create a real problem (for me) seeing things under shelving or anything out of direct view of the LED source. In fact, it was bad enough that when working on small parts on the bench, if my head came between the light source and the object, the shadow would prevent me from being able to see inside the object. I needed to add a head lamp. Not the case at all with incandescent.

Incandescent seemed to 'bounce' around much better under these types of conditions. Also, the lower temp LEDs, 2700k vs 5000k, seemed to create less shadowing but never as good as incandescent. I was using 100watt bulbs for both types and tried tube LEDS (as well as fluorescent which were almost as good as incandescent).

I thought maybe the LED didn't have as much energy as the incandescent type due to the temp of the light. But being just a guess, I'm really curious if anyone has a good explanation.

Thanks!

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#1

Re: LED shadow vs incandescent lighting

12/28/2021 12:57 PM

Thanks! That puts a whole new light on things!

I will re-think me shop lighting.

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#2

Re: LED shadow vs incandescent lighting

12/28/2021 2:01 PM

Your problem seems to be a combination of lumens, diffusion and color heat related ...shop lighting is usually in the 6500 - 7500 region...

You need a bright blue-white light with high lumens output for working conditions, and you need diffusion of the light to avoid glare and disperse the light...

https://www.ledmyplace.com/products/t8-4ft-v-shape-led-tube-30w-integrated-6500k-clear?variant=31263595277

I like to mix the colors in the high range to help with color rendering factor...2 equivalent of the 4 footers above for every 36 square feet of floor space should be adequate...

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#4

Re: LED shadow vs incandescent lighting

12/28/2021 4:46 PM

I think you're right.

Smaller light sources cast darker or sharper shadows. Incandescent lamps usually emit light in all directions, so they often have reflectors to redirect the light to the work area. The incandescent bulb plus reflector is a much larger light source than the LEDs. Being physically larger, they shine around objects, and so cast "softer" shadows.

If you've ever been in a total solar eclipse, you've probably noticed how sharper the shadows are when most of the sun is obscured.

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#5

Re: LED shadow vs incandescent lighting

12/28/2021 11:26 PM

In incandescent bulbs, light produced is multi directional from some length of the filament while LEDs are almost from a point and almost uni-dimensional .

Therefore shadows would be sharp and dark .

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#6

Re: LED shadow vs incandescent lighting

12/29/2021 12:50 AM

My preference is to use fluorescent daylight tubes for general workshop lighting with more lights set up to fill in the work area rather than more lamps per fitting. Daylight tubes give better colour rendering as well I use triphosphor tubes in kitchen areas.

No good around rotating machines, lathes, Mills, drills grinders but for those I use halogen downlights or incandescent lamps to provide concentrated lighting into the specific work area.

As you have noted leds are more of a point light source and have darker shadows making it harder to find small items that have fallen from the work bench into a parallel universe, or is that a perverse.

I am not a fan of the 4ft led tube replacements and find their light is more of a blue colour.

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#7

Re: LED shadow vs incandescent lighting

12/29/2021 1:50 AM

You don't specify which kinds of LED lamps you are using. There are literally hundreds of styles available. Any Lamp with essentially a single point source of light will cast sharp shadows, whether that source is incandescent, arc, LED, or whatever.

If you want soft shadows, then you need a diffuse light source, hopefully with large, rough-surface reflectors. I've found that the (slightly under) 4ft LED shop lights (from Costco) are essentially perfect for general shop lighting. Not only do they provide brighter and whiter light than the fluorescents they replaced, they also appear to have a good mix of phosphors such that I don't notice any flicker, as I did with the fluorescent lamps. Someone in this thread mentioned not using LED lamps around rotating machinery; I use these lamps above all my machines, including the lathe and mill, with no problems.

For close work, some form of additional light is needed. but the same concepts apply. I commonly use a "crookneck" lamp with a screw-in LED Lamp of the type that looks pretty much like an old-fashioned frosted glass incandescent lamp bulb.

I like the color temperature info that SE provided, but there is very definitely a LOT of personal preference involved. I'm rarely interested in using light to create a mood; I'm nearly always interested in being able to see fine detail. I gather that many people like the "warm white" color; to me, "warm white" is only slightly better than candles, and is clearly inferior to "cool white".

Finally, there is clearly a significant variation between people's needs/desires for light. Just as my hearing is weaker than it used to be, my ability to see is also apparently going downhill. My wife commonly works and reads with much less illumination than I prefer. She sets the brightness on her phone and computer display to a level that I consider very dim!

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#8

Re: LED shadow vs incandescent lighting

12/29/2021 2:08 AM

Bright white LED lights without a proper lens diffuser are glaring and produce sharp shadows....that's why lampshades and light globes exist...they do make LED bulbs and fixtures with diffusers...

... 36W LED Ceiling Light Fixture, 13in Flush Mount Light Fixture, Ceiling Lamp for Bedroom, Kitchen, Bathroom, Hallway, Stairwell, Super Bright 3200 Lumens, 5000K Daylight White...

https://www.waveformlighting.com/home-residential/aluminum-channels-for-led-strip-lights-are-they-worth-it-an-in-depth-look

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#9
In reply to #8

Re: LED shadow vs incandescent lighting

12/29/2021 2:28 AM

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#10

Re: LED shadow vs incandescent lighting

12/30/2021 9:47 AM

Thanks everyone !

You all have given some great suggestions and info. Having already tested the different temp lighting to no avail, I think lumens and diffusion sound promising to provide a solution. I'm going to run some real world tests and I'll post my results back here when I'm done.

As a side comment relating to one of the posts, I have occasionally noticed a strobe effect on some rotating equipment from fluorescent lighting but never from LED which does seem curious.

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#11
In reply to #10

Re: LED shadow vs incandescent lighting

12/30/2021 12:52 PM

Fluorescent lights provide a peak of illumination at each positive and negative power line voltage peak, so pulse at 120 Hz (in the US and other places that use 60Hz).

LEDs operate at vastly lower voltages, and the circuitry that provides the low voltage for the LEDs commonly contains a capacitor, which smooths out the peaks and valleys, so they give a very steady light.

On the other hand, LED flashlights that have a dim setting commonly use pulse width modulation to reduce the brightness, and so flash quite noticeably. That flashing occurs at a much faster rate than 120 HZ, so may or may not be observable on rotating machinery. It IS usually noticeable when used to illuminate rain or dripping water

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#12

Re: LED shadow vs incandescent lighting

12/30/2021 3:25 PM

How about this idea/fact. The intensity of the LED causes your irises to contract more than they would with incandescent, which in turn renders shadows less visible.

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