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-   -   White balance card (https://www.dvinfo.net/forum/photon-management/102673-white-balance-card.html)

Ian Stark September 2nd, 2007 08:37 AM

White balance card
 
Just seen a tip in an article that suggested laminating a piece of white paper and using it to white balance. It also suggested you could use a write on/wipe off board the same way.

Sounds like a reasonable idea but is there any issue with using a shiny surface for white balancing.

Adam Letch September 2nd, 2007 04:41 PM

I would initially have said yes
 
because we have a large peice of cardboard we use, one side is laminated the other not, and you get different results from each side.

Having said that, I have a portabrace white balance card, they're like $4.95 and thats made from plastic, but with a flat/matte finish using a textured surface, and I also have a DSC colour chart I use most of the time, which on the back is a white balance card, but its a smooth plastic. And that still works fine?

Any other thoughts out there?

Adam

Ian Stark September 2nd, 2007 04:59 PM

Ah, but doesn't light go the other way in the southern hemisphere? ;-)

I've used the WB card from (ex)Serious Magic's (ex)DV-Rack and that's a slightly shiny surface. 9 times out of 10 though I use any old piece of white paper!

If I'm honest, I can't say I have noticed any difference white balancing to any material in particular, but as time goes on (and as my clients go from Mom 'n' Pop to High Street names) I'm trying to be more and more professional about what I'm doing. This is done in the certain knowledge that sooner or later I will come up against another director/cameraman/whatever who will tell me I'm an idiot. I'd like to have a considered response up my sleeve.

I use a homemade 'slate' (actually a £2 write 'n' wipe board from a stationery store which I have marked up with 'production', 'shot no', 'date', 'tape ref' and 'take'). I think I'll just paint the reverse matt white.

Cheers.

Ian . . .

Bill Davis September 2nd, 2007 07:07 PM

Ian,

I'll also note that back in the days of analog production, white balance was a LOT more critical than it is today.

Today, every major NLE has the ability to correct white balance problems in post.

Sure it's nice to get it right in the field and I'm NOT arguing against good shooting practices. They are a sure sign of professionalism.

Just noting that I haven't seen a shot where the WB was wrong that I couldn't correct in a click or two in post for years now.

(same reason I don't mess with those "warm cards" or other WB accessories - you want a cooler or warmer shot - just dial it up in post.)

FWIW.

Glenn Chan September 2nd, 2007 08:08 PM

1- Fixing white balance in post doesn't give the exact same results as doing it right in camera. Things like knee settings will muck around with the highlight colors, so you can sometimes get weirdness in the highlights after you fix WB.

Also some of the color correction plug-ins fix WB by adding a color tint... but they don't clip away erroneous highlight colors (I'm not sure if this is a good explanation). So if in the original shot you have an overexposed blob of white, it will pick up a tint after you white balance. So that blob is no longer white.

But you can generally get the shot looking good, so it's not a huge deal unless you are way off with the white balance. And it definitely makes sense to get it right in the field.

2- There are subtle differences in the "whiteness" of an object. If the object doesn't reflect each wavelength of light equally, then it's not perfectly white. Usually our visual system ignores subtle differences in whiteness so it's not a huge deal. If you take two "white" objects and place them right beside each other, you will see the subtle differences.

That's the difference between the DSC chart and a DIY chart.

Other than that, in practice it's probably not something to worry about considering people are using warm and cool cards. (Which would technically be "wrong".) Though the DSC chart looks more professional, which might make a difference to your clients??

Brian Drysdale September 3rd, 2007 09:14 AM

I hate to get anti techy about this, but it was pretty standard practise on shoots with broadcasters like the BBC etc, just to use white paper - commonly a reportor/director's notebook or the call sheet. Although, in recent years you'd need to be more careful about some of the "colder" papers.

Often a 1/4 CTB gel was stuck in front of the lens to warm it up whilst white balancing.

Seth Bloombaum September 3rd, 2007 04:39 PM

Quote:

Originally Posted by Bill Davis (Post 738351)
...I don't mess with those "warm cards" or other WB accessories - you want a cooler or warmer shot - just dial it up in post...

I purchased warm cards and never used them, for the same reason as Bill.

Then, one day I was shooting under some sort of sodium-pressure or such stadium lights at an artificial turf field, and could *not* get the turf to look green by white balancing. I was glad I had the small warmcards in the camera case, they really helped that day, especially since I was handing off the tape to someone else to edit and I wouldn't be able to cc in post.

SOP at my first paying job at a TV station in the 70s was to use a cloth diaper to white our RCA TK-76 cameras, which also came in handy for mopping the brow on a hot day, or a thousand other uses.

Mike Cavanaugh September 4th, 2007 10:27 AM

Watch a news crew - 9 time out of 10 their station vehicle is white, and they use the fender to WB.

While run-n-gun videography isn't everyone's style - it works.

Heiko Saele September 4th, 2007 02:04 PM

I always use a sheet of paper to white balance and I'm good with that. I know the numbers my camera tells me when I w/b with white paper and so it works well even in mixed light conditions (like I want to get that "4000K" when it's tungsten but with a lot of daylight coming in through windows etc...).

I'm one of the news guys you're talking about - but I don't w/b on the hood of our car, I can w/b while walking with the camera on my shoulder (left hand grabs the camera's sunshade and the paper, right hand switches the w/b lever) :)

I always try to get the numbers a little higher than neutral - and if there's only one kind of lights around I like to use a 1/4 CTB on the lens. But that's only for our DXC D30 shoulder cams, the DVX100 and HVX200 are not neutral by default, they don't need any warming up.

Stephen Eastwood September 4th, 2007 09:00 PM

I use a WhiBal which are basically totally neutral and contain a pure black and white as well as a ruler of inch/centermeters if needed. I also mainly use a wratten filter to WB on such as an 82A or B or 81A or B or cc filters and then remove the filter to create the opposite effect while neutralizing any strange color cast present from bounce. This way I can shoot warm/cool or tinted without filtration on lens or after the fact color correction.

I will never understand why and when people got into the habit of shooting poorly and trying to fix it later. It goes to show a lack of respect for ones own work and that same mentality tends to bleed into other areas as well little by little. I hear make up artists saying on most still shoots "I wont bother with covering this or that up you'll just fix it in post...." I can easily do that, but why not do a better job in the first place? Hell, why should I light a scene or pictures we can just flat light everything and fix it in post, so it will take a little longer and look like crap, its easier than having to carry more lights and think of where to put them.

I live for retouching, I love to use it to perfect that which is not, and do things beyond the capabilities of the situation on occasion, but I hate having to fix laziness, maybe its a work ethic issue. Maybe its just me?


Stephen Eastwood
http://www.StephenEastwood.com


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