RGB LED

Joe Farina · Post by **Joe Farina** » Mon Oct 07, 2013 8:20 am

Today I ordered one of these, but it will take a while to get here. It's a RGB LED light bulb, which they claim has millions of color variations, with remote control.

I want to find out if this has a single RGB LED or multiple LEDs (i.e., if the emitters are located in a fairly small area). There must be multiple emitters, but if they are clustered together in a small area (somewhat "spatially coherent" as a whole), it should be OK for illuminating holograms. I will need to remove the diffuser in front.

http://www.ebay.com/itm/300673002025?ss ... 1497.l2649

This might be useful for multi-color holograms, perhaps as a diagnostic tool.

a_k · Post by **a_k** » Sun Oct 13, 2013 5:51 am

Hello Joe,

The diffusor in front of your RGB might be disturbing when used to illuminate holograms. Other high power LEDs have their emitters exposed and come closer to being ideal point light sources. You can get kits with the remote + IR receiver/driver for RGB and a more suitable RGB LED. Or a set like yours, but with a clear bulb with reflector like this one:

http://www.ebay.com/itm/NEW-3W-4W-E27-1 ... 5d44e121a0

The millions of colours (2^24 usually) are generated by modulating the intensity of each of the 3 colours, not by actually changing the emitted weavelengths. What you have are 3 bands with a width of about 20-30nm each.

Joe Farina · Post by **Joe Farina** » Sun Oct 13, 2013 10:34 am

Hello Ahmet,

Thanks for the link and information. The diffuser on the one I ordered will most likely be a problem as you said, but I was planning to remove it. (I don't know what I'll find underneath.) The good thing about the one you linked to is that the emitter is visible, and the cover is clear. I almost ordered one like that, but I hesitated because they said "16 colors" instead of millions. Probably these are all basically the same, with millions of colors possible, but I hesitated because it wasn't clearly stated. I haven't been keeping up on RGB LED technology, so thanks for the clarifications. Once mine comes in, I will remove the diffuser and see how it works, and order one like you mentioned, if needed.

With the two-color holograms I've done, the effects can become odd and inexplicable. Reconstruction sources have a very drastic effect on the colors of the image. The color variations possible with a RGB LED might help me to get a better grip on things. I have taken a long break from making holograms to re-organize my layout, lab, etc., but I'm starting to get geared up again.

lobaz · Post by **lobaz** » Wed Oct 16, 2013 4:53 am

Well, it is necessary to test. For example, look at these two:

: Halogen, clear

: LED, diffusor

I would expect the first one (halogen) to be better, but opposite is true! The image reconstructed with the LED is much sharper - check the ear or the shoulders.

: Halogen illumination

: LED illumination; led_hologram_mini.jpg (48.27 KiB) Viewed 3084 times

(The hologram is 26x36 cm by Alex Gontar)

Petr

Joe Farina · Post by **Joe Farina** » Wed Oct 16, 2013 7:24 am

Thank you Petr for posting those photos. The LED-illuminated image is indeed sharper. It seems that whenever a hologram is slightly blurry, it detracts quite a bit from the overall impression, but when everything is sharp, the results can be spectacular. By the way, that is a very high quality portrait hologram.

It appears from the box of the LED bulb that it's only 4W, yet it does a superb job of illuminating the hologram.

142laser · Post by **142laser** » Wed Oct 16, 2013 8:09 am

I think variable LED illumaintion with bright LED's can really enhance hologram display; something new to play with for you guys! Cool. Need an RGB control box...

BobH · Post by **BobH** » Wed Oct 16, 2013 8:59 am

I expect the LED lamp above to be much better. The narrow spectral bandwidth takes away the color blur, and the smaller diameter of the effective source reduces source size blur. Excellent portrait by Alex Gontar! The BEST color for portraits, if it stays that color. Keeping it out of ALL direct sunlight and only illuminating it with the LED will help tremendously toward that. NEVER illuminate reflection holograms on silver-halide with the sun. Never, never, never!

Dinesh · Post by **Dinesh** » Wed Oct 16, 2013 9:02 am

This was made with an led, about 2003. This kind of display can only work with an led. It was made for a Medal of Honor recipient and his medal floats about 2in in front of the background

Joe Farina · Post by **Joe Farina** » Wed Oct 16, 2013 1:50 pm

This is another LED which I will be testing:

http://www.ebay.com/itm/360641859342?va ... 1439.l2649

The one I ordered is a 30W warm-white outdoor floodlight. I need a warm-white LED for a general-purpose inspection light for holograms.

Joe Farina · Post by **Joe Farina** » Thu Oct 17, 2013 9:38 am

Here's another I bought for testing, this one shouldn't need modification.

http://www.ebay.com/itm/171041174275?ru ... 26_rdc%3D1