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-   -   Fluorescent vs skin tone (https://www.dvinfo.net/forum/photon-management/142352-fluorescent-vs-skin-tone.html)

Donald Blake January 25th, 2009 02:16 PM

Fluorescent vs skin tone
 
2 Attachment(s)
Hi everyone,

I built a home made lighting kit (see JPGs) I used 3 basic lighting fixtures, they each have 2 48" T8 fluorescent tubes. Basically they're sold to be used in garages (I know I'm not the first one to do this) I have 6-6500K tubes for cold type lighting and 6-3200K tubes for wharm also.

So here's the situation;
From rescent tests I made the cold lighting makes the skin look yellowish, I want to have that regular pink skin look, even in post production with the color correction I'm having a hard time getting it. With the warm lighting tubes the skin turns out ok yet you can still notice a bit of yellow in there.

I have a camera F-DL filter which I tought would fix my problem but it dosent seem to change much, I tested the warm and cold White balance on my camera and can't seem to find the right settings or combination of all this.

Thanks in advance!

Perrone Ford January 25th, 2009 02:24 PM

Does your camera have a white balance button? Do you have a white card or a white sheet of paper? If yes to these, you should be able to do what you need.

Seth Bloombaum January 25th, 2009 04:48 PM

Perrone's post refers to one of the potential problems - a mismatch between the color temp of your cam and the tubes.

Another potential problem, maybe your tubes aren't sufficiently full-spectrum. Exciting the gasses in an flo tube to glow isn't enough to provide good color, the manufacturer also coats the inside of the tube with phosphors that glow (edit: the right phosphors will even out the color rendition). A tube that is good for video will have a relatively high CRI (color rendition index), meaning relatively more full-spectrum light than something sold for the garage.

Most tubes are now a lot better than the days in which most fluorescent lighting was truely heinous even to the eye, but of course the camera is a lot more discriminating.

So, if you're still unhappy with color rendition after the custom white balance that Peronne recommended, you may be shopping for new tubes. Sometimes hard to find the actual CRI info, sometimes easy, but you're probably looking for 85 or better.

Cool-looking fixtures, btw :-)

Steve Rusk January 25th, 2009 08:50 PM

To add to what Seth already pointed out, the best CRI rating I've seen outside dedicated Kino Flo bulbs was called Sunstick (or something like that) from Lowe's. It had a CRI of 90 and a color temperature of 5000K. They had been $20 for a box of 10, but last time I saw them, the price had jumped to $29. Still a bargain for good lighting.

Donald Blake January 26th, 2009 11:10 AM

1 Attachment(s)
Ok I managed to get the CRI info and it's at 78.

Take a look at my JPG (taken from post-production) and here's all my setings, tell me if you see something wrong ;

LIGHTING :
6 - T8 48" 6500K 78CRI tubes, horizontal with reflectors right next to the camera (60" from subject)
2 - T8 48" 6500K 78CRI tubes, vertical on the back side of the subject.

CAMERA (HDR-FX1) :
0 gain
F3.1 Iris
60 Shutter Speed
White balance set with a white piece of paper at the subjects exact location

POST-PRODUCTION (vegas) :
+0,15 contrast added
+1,20 saturation added
+0,05 red added (midtones, color balance)
+noise reduction (smart smoother)

Ok forget about the background, would this be acceptable for a information video where the subject talks about a product or a company? thanks in advance!

Perrone Ford January 26th, 2009 11:27 AM

It's hard to judge the colors because half the frame is clipped.

CRI of 78 is a bit dicey to me. I'd feel a bit uncomfortable working below 85.

Donald Blake January 26th, 2009 12:04 PM

1 Attachment(s)
Sorry Perrone I should've specifyed that the JPG you saw was just a test and the final product will be in front of a green screen, So never mind the surrounding color what I'm looking for is the Skintone color.

I tought the skintone was a little pale, so I did another one and added saturation (1,30) and took out brightness (-0,10) see my new JPG

For the CRI issue, I'll be on the look out for higher CRI tubes, but for the moment that's what I have.

Perrone Ford January 26th, 2009 12:29 PM

Can you drop an unprocessed frame grab on my FTP server? The link is in my profile. Just drop it at the root. But don't do a jpg. Do a PNG, or Targa (TGA), or a TIFF if that's all you can do. These JPGs are just to blocky for me to make any reasonable comment about the skin tone.

Donald Blake January 26th, 2009 02:23 PM

Done .

Doug Bennett January 26th, 2009 02:50 PM

the image has a blue/green cast - I would guess partly due to low CRI and partly incorrect white balance.

You cannot accurately determine WB for a 3 dimensional object by measuring the reflection from a piece of card - use a monitor or plug the cam into a laptop and use the scopes in the NLE.

Perrone Ford January 26th, 2009 03:01 PM

Mailed you back after making a few corrections.

-P

Donald Blake January 26th, 2009 03:39 PM

Ok thanks Perrone, I'm looking at your PNG and it looks more lifelike than mine, can you explain what effect did you add to it or send the VEG files in your reply?

Donald Blake January 26th, 2009 03:44 PM

Doug, is that what you do everytime you film something? you always have a laptop plugged to your camera? and what program are you using (NLE)?

Dave Dodds January 26th, 2009 03:47 PM

So the only problem is that you think she's a bit pale? Is she pale in real life? Perhaps all you need is a little warmth, like an 1/8 cto or even a cosmetic pink on the flo (WB first without the gel).

From a quick look on a regular computer monitor, I don't really see a problem with her skin tone. It looks pale, sure, but not unnatural. If the paleness is the only problem, all you really need is what I mentioned above.
Good luck.

~~Dave

Donald Blake January 26th, 2009 04:05 PM

Quote:

Originally Posted by Dave Dodds (Post 1001556)
So the only problem is that you think she's a bit pale? Is she pale in real life?

Actually the original problem (if you read the very first post) was yellow skintone with the fluorescent lighting.

And she's actually tanned in real life.

I'm having a hard time finding the right settings or should I say the right mix (lighting/camera/post-prod), I'm doing a lot of testing and I can't seem to get that winning combination. Ok I don't have the yellow skintone anymore but I don't have her real skintone either.

Can overlighting the subject ruin everything in post-production? my Iris was open at 3.1 maybe I should've closed it a bit more?


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