Completely white background, how to?

[Bro Photo]

Hai gais! Lately, I've been doing a lot of shoots requiring a completely white backgrounds...I've been doing fairly well with consistent lighting but 2 hotshoe flashes aren't providing enough power to overexpose the white vinyl backdrops that I use.

The way that I blow out my white backgrounds is dodging the highlights @ 10-35% opacity with the "preserve tone" unchecked. But when I open up levels and drag my midtones to the right, it still shows detail in the highlights...
That and sometimes the background can have a color tinge to it and not be completely white. How do I make my backgrounds completely white without using the eraser tool or white paint brush?

[namphoto]

Two external flashes, at full shot through an umbrella, softbox, or even bounced of large white v-flats are more than sufficient to blowout a background. It's all comparative to your mainlight. I don't know the exact ratio, 5:1 6:1? I have no idea, but raise your aperture drop your key lights, and it'll blow the background out.

When you say white vinyl background.. is the background material vinyl, like that shiny stuff.. because if it is, your subject will have pretty darn far away from the background so that the light isn't reflected off onto the subject's shoulder.

Once you've shot it right, simply use a raw converter to find white balance so you don't have any color shifts on the white, and it's probably a good idea to check for chromatic aberration. In photoshop you can manually find white balance by checking with numbers (if you don't know, you can search it).

Sometimes you mess up, so photoshop is your friend. Create a levels adjustment layer, slide your shadows slider nearly a third of the histogram to the right. Make sure you have a duplicate of the original image and use your dodging tool, set to highlights (if its selected at shadows or midtones, this may be why your highlights aren't being totally blown out), opacity ususally 15 - 10 %, and just over and over trace around your subject. Try to be careful at this point, but if your brush hits the subject then it usually isn't that big of a deal. When done, make sure you delete your levels adjustment layer. Good luck.

[Bro Photo]

Originally Posted by namphoto

Two external flashes, at full shot through an umbrella, softbox, or even bounced of large white v-flats are more than sufficient to blowout a background. It's all comparative to your mainlight. I don't know the exact ratio, 5:1 6:1? I have no idea, but raise your aperture drop your key lights, and it'll blow the background out.

When you say white vinyl background.. is the background material vinyl, like that shiny stuff.. because if it is, your subject will have pretty darn far away from the background so that the light isn't reflected off onto the subject's shoulder.

Once you've shot it right, simply use a raw converter to find white balance so you don't have any color shifts on the white, and it's probably a good idea to check for chromatic aberration. In photoshop you can manually find white balance by checking with numbers (if you don't know, you can search it).

Sometimes you mess up, so photoshop is your friend. Create a levels adjustment layer, slide your shadows slider nearly a third of the histogram to the right. Make sure you have a duplicate of the original image and use your dodging tool, set to highlights (if its selected at shadows or midtones, this may be why your highlights aren't being totally blown out), opacity ususally 15 - 10 %, and just over and over trace around your subject. Try to be careful at this point, but if your brush hits the subject then it usually isn't that big of a deal. When done, make sure you delete your levels adjustment layer. Good luck.

Thanks for the reply, I got my wording wrong. Atm, I'm lighting the background with 1 flash and the subject with the other flash thru an umbrella. I suppose I could increase my aperture but I'm usually shooting around f/5.6 and any wider, I'd risk having uneven focused body shots. :s then again I could increase ISO...the vinyl is porous and doesn't reflect much light, so spill isn't really a concern.

I shot with a custom WB but it wasn't with 18% gray. I'll do a search about the numbers.

The dodging way you described is exactly what I do but with heavier opacity and with levels adjustment but eliminating midtones to expose the data in the highlights. Yet still there's some artifacting in the shadowy areas that I dodged, I usually notice this when I tilt my screen. It's like spotting dust in my viewfinder

I don't have much problems with CA, (thanks to L lens ) but I could see how that would add problems when dodging out the BG.


Thanks for reply!

I read somewhere you can pinpoint the beginning of the highlights and clip it via curves but I can't seem to find it again... Shoot!

[Algarve Images]

As Namphoto has already mentioned the ratio is important and an ideal high key setting would be 4 lights, for example if the subject reading is F8 then the two backlights burning the BG should be F11..
There is a diagram here at:

http://jerrycentral.com/2008/07/09/h...hting-diagram/

Another method, easier if you have a sunny window to place the subject in front of it make sure it has net curains or even better a white silk blind to diffuse the light.
Use fill flash, bump up the ISO and your bg should be burned out.
Here's an example taken in a living room against a bright window with only fill flash...
1/60 @ F4.5
ISO 1600
I underexposed the original so you can see the window, the covering is a net curtain and it worked...
Regards,
Gary...

[Bro Photo]

Oh! Thanks for the link Algarve Images. If I'm not mistaken the diagram looks like there's only 3 light sources and a reflector. I'll be ordering some Alienbee's this week so lighting will be a lot more easier to manage.
Good example picture too! But I don't think commercial photography would benefit from the light bleed :/ or 1600 ISO haha! Actually, that looks pretty clean.

But since this thread is in the post production section, does anyone know any other alternatives or more efficient ways to correct imbalanced BG lighting?

[Flora]

For the colour tinge, you could try with a Hue/Saturation Adjustment Layer:

• pump up saturation to 100% to identify the colour cast/casts
• Go to the 'guilty' colour/s and decrease the saturation completely and increase luminosity to 100%

If necessary add a Selective Color Adjustment Layer go to the Whites and decrease the black completely.

Of course, it would be easier if you could post the problem part of your image...

[Bro Photo]

Originally Posted by Flora

For the colour tinge, you could try with a Hue/Saturation Adjustment Layer:

• pump up saturation to 100% to identify the colour cast/casts
• Go to the 'guilty' colour/s and decrease the saturation completely and increase luminosity to 100%

If necessary add a Selective Color Adjustment Layer go to the Whites and decrease the black completely.

Of course, it would be easier if you could post the problem part of your image...

Thanks for the info! The pictures are on hold by the company I work for but I think I can swing an upload since I took them.

[Bro Photo]

Here's an unedited, resized and compressed image I took a few days ago for a website.
When dodging out the highlights and edging into the underexposed areas there's some data left when I adjust my levels. Sometimes when I create marques and hit delete which leaves behind 255/255/255 RGB white, my background is subtly noticeable alongside the white deleted areas. It's not that bad but I'm really anal about pp'ing simple photos like this one.

You can see (well I can at least @_@) a yellowish tinge artifacting around the left girl if you tilt your screen slightly. Haha, I feel pretty goofy about such little details you can barely see.

[Algarve Images]

Originally Posted by Bro Photo

Oh! Thanks for the link Algarve Images. If I'm not mistaken the diagram looks like there's only 3 light sources and a reflector. I'll be ordering some Alienbee's this week so lighting will be a lot more easier to manage.
Good example picture too! But I don't think commercial photography would benefit from the light bleed :/ or 1600 ISO haha! Actually, that looks pretty clean.

But since this thread is in the post production section, does anyone know any other alternatives or more efficient ways to correct imbalanced BG lighting?

Yep,
looks like 3 lights and thats good for me too as i've ordered 3 elinchrom's from UK.
The D3 is clean up to 1600 and usable at 3,200/6400 for smaller prints, at 800 ISO there is no visible diference from base ISO of 200

[Flora]

Hi again,

using the Hue/Saturation at 100% saturation on your original you can see the different tinges in your background: yellow, red, magenta etc. and there are also a couple of patches of grey. (Attachment 1)

So, even before seeing your corrected version, I also opted for a selection and simply used a Levels Adjustment layer on the selected background.
(Attachment 2) from left: original, white background, adjusted luminosity particularly on the girls faces + lightly increased saturation.

After seeing your correction I used Hue/Saturation at 100% saturation on it and saw what you meant about the very light tinge specially around head and feet of the girl on my left. (Attachment 3)

Probably, the selection you made wasn't very accurate that's why those spots had retained a subtle colour cast. Reselected the background, I used a Selective Color Adjustment Layer (Attachment 4) and the tinge disappeared.

[jerrycentral]

You can use any type of lighting for the front. One light is good but you could also use a main plus fill. You can certainly do this with 3 lights.
JerryCentral

[Bro Photo]

Originally Posted by Flora

Hi again,

using the Hue/Saturation at 100% saturation on your original you can see the different tinges in your background: yellow, red, magenta etc. and there are also a couple of patches of grey. (Attachment 1)

So, even before seeing your corrected version, I also opted for a selection and simply used a Levels Adjustment layer on the selected background.
(Attachment 2) from left: original, white background, adjusted luminosity particularly on the girls faces + lightly increased saturation.

After seeing your correction I used Hue/Saturation at 100% saturation on it and saw what you meant about the very light tinge specially around head and feet of the girl on my left. (Attachment 3)

Probably, the selection you made wasn't very accurate that's why those spots had retained a subtle colour cast. Reselected the background, I used a Selective Color Adjustment Layer (Attachment 4) and the tinge disappeared.

Thanks a bunch, Flora. Very informative! I just didn't want to spend additional time trying to correct color casts...etc. Because I work with time sensitive projects. Even dodging out the highlights take a lot of time and I want to be as efficient as possible!

[Bro Photo]

Originally Posted by Algarve Images

Yep,
looks like 3 lights and thats good for me too as i've ordered 3 elinchrom's from UK.
The D3 is clean up to 1600 and usable at 3,200/6400 for smaller prints, at 800 ISO there is no visible diference from base ISO of 200

Nice, I own a 5D and it does nicely @ higher ISOs, too bad it doesn't have an integrated portrait grip and current AF/ISO performance... >.<
WTB 1D Mark III!

[jerrycentral]

Originally Posted by Algarve Images

As Namphoto has already mentioned the ratio is important and an ideal high key setting would be 4 lights, for example if the subject reading is F8 then the two backlights burning the BG should be F11..
There is a diagram here at:

http://jerrycentral.com/2008/07/09/h...hting-diagram/

Another method, easier if you have a sunny window to place the subject in front of it make sure it has net curains or even better a white silk blind to diffuse the light.
Use fill flash, bump up the ISO and your bg should be burned out.
Here's an example taken in a living room against a bright window with only fill flash...
1/60 @ F4.5
ISO 1600
I underexposed the original so you can see the window, the covering is a net curtain and it worked...
Regards,
Gary...

I looked at your web site ... Nice work. I did notice a few of your High Key shots showed a little flare that degraded your contrast. Flare is quite a problem with high key so make sure that you have a clean lens and use a lens shade. If your background is too bright it will make flare. We try to light the background until it just starts to blink with over exposure on the LCD. The Black cards are also helpful in shading the lens and keeping the background lights from spilling on the subject.

[W.Smith]

Not to put too fine a point on it, but the secret is not so much in the light intensity ratio between subject and a white background, but in the light intensity difference between those two. That difference needs to be 2 stops. I.o.w. the white background needs to reflect 2 more stops of light into the lens than the subject does. You achieve that by throwing much more light on that background than on the subject. (But too much, and you get flare. It's a precise balance).
This is where spot metering – but better yet: a separate flash meter – comes into its own. OTOH: simple test shots (with a stand-in 'subject', like a mannikin) help you find the ideal lighting setup ahead of the actual session.

When there's no going back to the set to reshoot you can try to rescue the shot in PP. The simplest way I sometimes use, if the photo lends itself to it (wispy hair is a killer): make a copy. Open it. Precisely select the subject. Invert the selection, so that the background is selected instead. Overexpose (In PS/CS3: Image–>Adjustments–>Exposure) by 2 stops. Voila!

[Algarve Images]

Originally Posted by jerrycentral

I looked at your web site ... Nice work. I did notice a few of your High Key shots showed a little flare that degraded your contrast. Flare is quite a problem with high key so make sure that you have a clean lens and use a lens shade. If your background is too bright it will make flare. We try to light the background until it just starts to blink with over exposure on the LCD. The Black cards are also helpful in shading the lens and keeping the background lights from spilling on the subject.

_________________________________________________________________
Thanks Jerry,
that was my first and only time in a studio, i do remember that there were no black cards to reduce light spill and i did have a lens shade, on the wrongway of course lol , we were packed in like sardines, 6 on the couse and very little space for manouvre, i am so glad i shot raw + jpeg, gradually i am altering the white balance and reducing the ghosting/flare on all the shots little by little.
Eventually when i get my lighting set up, i'll have months to experiment and get used to how it works (just been told the system is still out of stock so will have to wait a bit longer)
W. Smith has a good idea...("a stand-in 'subject', like a mannikin") for a dummy run (excuse the pun) immediately my mother came to mind he he... god bless her
regards,
Gary
ps... Jerry your website is very informative, will be visiting over there on and off

[Algarve Images]

A quick note,
have been on the phone to my Nikon dealer in the UK, quite apart from convincing me to buy 4 elinchroms now arghh! he mentioned Lastolite who have the portable Hilite bg in which lights are inserted and zipped up inside, one or two depending on size of the bg, the advantage is portability and it can also be used in a much smaller room (allegedly) because the subject can be positioned very close to the bg without creating shadows.
Anyway there are loads of video tutorials on the site re: hi key
http://www.lastolite.com/video-demos.php
Might be of some help, also there's some may be relevent stuff on photoshop...
regards,
Gary

[jerrycentral]

Gary
We just bought 4 Elinchrom 600rx monolights with the skyport radio system and we are happy with them except that we can not use our umbrellas with them. They require a 7mm umbrella shaft and all our umbrellas are larger. We are happy with the Elinchrom, they are nicely built and have a fast flash duration that we like. You will have plenty of power with any Elinchrom lights, and your High ISO performance will never be needed. A problem you may have is getting the light low enough to put you light where the need to be ..... VERY CLOSE!

I have been a professor of photography for 28 years and have taught portrait photography for all of those years. So I may get teacherly because that's my job. Sorry!

I just found this site because of your link back to my blog and it looks like an interesting forum.

[Algarve Images]

Thats good to hear Jerry, glad i went with Elinchrom, have ordered the lastolight Highlite also as it can double as a huge softbox,
regards,
Gary

[Bro Photo]

I think I'm going to order 3 alienbee's AB800s to start out with and build up from that.

[holgaman]

One method I like to use is the Replace Color adjustment. Make a new layer first, and then go to Image - Adjustments - Replace Color. Make sure the localized color clusters box is checked (CS4), and then slide the fuzziness slider all the way to the left. Click on the background and then hold the shift key while dragging the cursor through the area you want to affect, watching the display in the Replace Color box as you go. Don't go too far, you want to add the last bit with the fuzziness slider to make the edges of your selection smoother. Then go to the saturation slider and set it at -100 and up the lightness to where you need it . If you did select a bit of the subject, you can cover that up later with a black brush on a layer mask. It's pretty fast and easy and does a nice job one you've gotten used to it.