Which has the highest CRI? (Just for fun)

Check this post for voting:

QUIZ ANSWER:

Why link to a post when you can just copy it so no one has to follow the link?

1. Didn’t plan this quiz. Already started there. The comments and opinions are very interesting and spark interesting topics.
2. I want all the discussions grouped in there. To make new visitors know what we were discussing

- Clemence

Who can explain to me which rule was broken in post #3?

Please tell me RC

- Clemence

Someone reported my post, and I don't have the foggiest idea why.

Definitely not me RC because I knew it was a good intention. I rarely use that button. I usually just post my expression or simply use PM. You can ask SB.
Few days ago I accidentally clicked that button while tried to push the post number (“#xxx”) at far right corner of the post box. That could be your case too

- Clemence

I'm glad it wasn't you.

I don't think so.

After clicking the report button, you have to confirm that you really want to report the post.

Well, I clicked the spam button. Off course I clicked back button immediately. I don’t know if that counts or not.

- Clemence

Do we need more votes? The test is very onesided.

Agree, looks like more votes wouldn’t yield different result. I’ll reveal the answer once the electricity goes back. It’s been 30 minutes out so far.

- Clemence

I was really hoping #4 would turn out to be a low-CRI light. It’s the obvious “correct” answer because the white shades in its image are actually white with equal values for R, G, and B. But the other three have some tint in their white areas — #1 is greenish while #2 and #3 are rosy.

But looking at the revealed answers, it doesn’t really fit the photos. Based on the measured Duv, #2 should be the greenest by far, but its image instead has a pink tint. And in person, #1 should look blue, but in the photo it doesn’t.

Usually when I photograph low-CRI lights with auto white balance, it comes out pure white. And when I photograph high-CRI lights with auto white balance, they tend to have slightly off-white shades. The result says more about the white balance algorithm than it says about the emitters.

Wait, I’ll publish the RAW files for anyone to check it. I used DxO Optics software for the conversion along with it’s built-in color rendering index profile. Stitching done with ACDsee.
EDIT: pic #2 is not rosy, it’s brownish actually

- Clemence

Why I can’t post google drive links in here? I always returned back to blank post

Ah, no more than a single link

Here you go TK:
https://drive.google.com/open?id=1mge2dx6qvCSkYAWcQ6ER1GLScdYjawxC

- Clemence

I'm voting for all the above .. because that would just be sneaky .

#5

This was more of a TINT question since the CRI is very high and indistinguishable.

But the difference in tint is very very evident. Ant that is why the optisolis won hands down. That is some amazing tint neutrality. Amazing LED.

Using the white section in the upper-right corner of the image, blurred to get an average color, the values I’m seeing are:

  1. R,G,B = 233, 238, 232
  2. R,G,B = 246, 243, 238
  3. R,G,B = 243, 239, 234
  4. R,G,B = 233, 233, 233

Normalized to 100%, the values are:

  1. 97.9, 100, 97.4 (greenish)
  2. 100, 98.8, 96.7 (pinkish)
  3. 100, 98.4, 96.2 (pinkish)
  4. 100, 100, 100 (pure white)

This is why I assumed #4 would get the most votes… because it’s actually white. However, I also guessed that #2 or #3 would be the ones with the highest CRI because lights with high R9 values usually show up a bit pink in pictures.

If #2 has a +0.0038 Duv and #3 has a –0.0011 Duv, but they have nearly identical pink-ish tints in photos, that basically means there was an error on the camera or in post-processing. Accurate color temperature correction would have produced different results for #2… something like this:

  1. 97.9, 100, 97.4 (greenish)
  2. 94.0, 100, 94.0 (green)
  3. 100, 98.4, 96.2 (pinkish)
  4. 100, 100, 100 (pure white)

… and in this case, the 92.5 CRI emitter in photo #2 would produce worse photos than the 74.8 CRI emitter in photo #1, because its tint is more green.

Thanks for the thorough inspection TK. I did nothing but take the pictures, convert, stitch, and upload. You can check the EXIF data to double check if it’s the camera or the post processing that cause errors. I took each picture twice using the camera built in double exposure. This is the only quick way to get even lighting without making a dedicated lightbox. I only use 5600K WB because this is what I’ve been using since the first time I uploaded pictures in BLF. I like consistency
If anyone think I must redo the supposed to be “Just for Fun” quiz, I’ll do it no problem. Didn’t mean to misled anyone, it is what it is. Don’t forget to include monitor limitation into consideration.

- Clemence

… those all used 5600K white balance?

The differences should look pretty dramatic unless they were re-balanced at some point. There’s no way a white sheet actually turns out pure white when the light source is 4852K and the camera is 5600K, even if the CRI is 100.

No, of course not. :slight_smile:

It’s just kind of a recurring topic with a long history of debate. Some people insist CRI can only be seen in person, others insist it can be seen even after passing through a camera, a 3-channel image file, the internet, and a 3-channel screen.

Me, I think CRI is pretty noticeable in person but basically impossible to represent accurately onscreen.

Er, unless a spectrometer is used, I mean. That allows us to get around the 3-channel limit.