white balance - preferred methods?

[stewarthemley]

I have a question about white balance. I find the cards that came with my H3D2-39 (haven’t got them with me -  the narrow ones with three grades on) to be quite unreliable. Having taken a shot at the location, and then using it in Phocus (2.5) to set the balance I only have to click a few pixels away to get a very different balance. This seems to be as hit and miss as guessing it myself. In fact, right now I've stopped bothering and just use what feels best from my (calibrated) monitor. This is not a Hasselblad problem as I have the same problem with a Phase back I sometimes use and also my Canons.

So, the question is, what do people favour? Expo disc? Whibal cards? Etc... And do you find them reliable/accurate? Any advice would be gratefully received. Cheers.

[Jack Varney]

I use the Greytag Macbeth color checker and the WhiBal.

[Gordon Buck]

Please note that I'm not a pro but I suspect that many do as I do.  I have a Whibal card but usually (forget) don't use it.  I find something that is "white" (as I recall) and convert from RAW using that "white" (often clothing) as the color balance.  I compare that "white" reference to the camera auto white balance and the ACR auto white balance and make a decision.   In the process, I may click on several different areas.  Then I stick with that decision for consistency with other images from the same shoot.

[JoeKitchen]

I have found that the expo disc is only totally accurate when you take a shot with it while looking at the dominant light source; most of my work is a mix of direct sunlight, strobes and gelled tungsten, using that can be impractical.  I typically use either a WhiBal or a white piece of paper to correct on, then eye ball it a little if I feel there is a need.  Most of my clients are not super anal about making sure the color is dead on accurate, so usually that method is fine.  

If they do need things absolutely perfect, I tell them either we shoot at night with no sunlight with straight tungsten lighting, or you are going to have to accept some variation since strobes only fall in the range of sunlight and rarely match it perfectly.

[LKaven]

I use the X-rite Color Checker Passport, and take shots of the gray card and color chart respectively at the start of each session.  Usually the gray card works, but if you need closer matching, it comes with profiling software for making DNGs from your RAW files that works off your image of the color chart.

[stewarthemley]

I have found that the expo disc is only totally accurate when you take a shot with it while looking at the dominant light source; most of my work is a mix of direct sunlight, strobes and gelled tungsten, using that can be impractical.  I typically use either a WhiBal or a white piece of paper to correct on, then eye ball it a little if I feel there is a need.  Most of my clients are not super anal about making sure the color is dead on accurate, so usually that method is fine.

Thanks for the replies so far - very interesting.

I had expected the Expo disc to be my answer but Joe's reply seems to indicate otherwise. My lighting is often mixed too - offices, interiors that are too big to light, etc so at this point Whibal and/or Gretag color checker are looking good.

[JonathanBenoit]

Thanks for the replies so far - very interesting.

I had expected the Expo disc to be my answer but Joe's reply seems to indicate otherwise. My lighting is often mixed too - offices, interiors that are too big to light, etc so at this point Whibal and/or Gretag color checker are looking good.

Don't bother with interiors. Use consistant daylight balanced lighting as best you can. At that point, you are mixing usually 3 or more light sources and it is impossible to get it completely accurate. Just go by your eye.

no such thing as interiors that are too big to light.

[K.C.]

I use a Minolta color meter and the grey/white Phase One stepwedge.

They never agree and more often then not the color meter reading is what I go with.

[SecondFocus]

I shoot a frame or two at the beginning of any series with an assistant holding the Gretag color chart. But as you can see, hanging around my assistants neck is one of those gray balance cards too. If we are moving fast and the color chart is on the other side of the room or misplaced I have the gray card handy.

This was shot with a Mamiya DM33 and Profoto lighting, some sunlight coming in through the glass doors.

[LKaven]

Thanks for the replies so far - very interesting.

I had expected the Expo disc to be my answer but Joe's reply seems to indicate otherwise. My lighting is often mixed too - offices, interiors that are too big to light, etc so at this point Whibal and/or Gretag color checker are looking good.

The X-rite Passport has a mixed light method too.  You can set up two color profiles, corresponding to two different lighting types in the scene, and it will provide for a continuous range of interpolated adjustment.  So presumably you can variably tilt the balance between one source and the other.  I haven't tried this myself yet.

[stewarthemley]

Don't bother with interiors. Use consistant daylight balanced lighting as best you can. At that point, you are mixing usually 3 or more light sources and it is impossible to get it completely accurate. Just go by your eye.

no such thing as interiors that are too big to light.

Agree with the first part of your reply, Jonathan, and that's pretty much what I do. (Edit added...) although I'd like something more predictable if possible/practical.

'Fraid I disagree with the last bit though - at least with the budgets I'm getting these days!

[Frank Doorhof]

Never use clothing or paper.
There is always a colorcast in clothing due to the whitenings used in manufacturing and washing powders.
Same for paper, a normal sheet of paper is too blue.

We're using the Colorchecker passport on location, it's very fast to use and you can also use it for a quick colorbalance by clicking on the series of grays.

[stewarthemley]

Thanks again for the replies.

Just checked the X-Rite passport and it looks good. I like the case concept, which seems quite rugged, I have a long-term contract for a big building project - loads of dust, etc - and it seems to provide quite a few options.

Still interested in hearing from any real-world problems with various systems. I think that's useful for quite a few folk here. Cheers guys.

[yaya]

Stewart, some softwares allows you (in the preferences or elsewhere) to adjust the size of the picker tool which is used for Grey balance. If you use a larger picking point (e.g. 9X9 instead of 3X3) this may help overcoming the Kodak sensor's tendency to produce non-uniform Grey colours. I don't know if Phocus offers this option but you should check.

Yair

[LKaven]

Never use clothing or paper.
There is always a colorcast in clothing due to the whitenings used in manufacturing and washing powders.
Same for paper, a normal sheet of paper is too blue.

Even worse is when they use those bleaches for diffusion fabric in cheap softboxes.  That polluted light is almost impossible to balance short of full profiling.

[Dustbak]

I currently only use the Gretag Macbeth color checker inside. I have tried several others but none of these were to my satisfaction. Outside I balance to what is pleasant in my eyes. If I needed to have correct colors I would get myself one of those X-Rite color passports as well.

Indeed paper is bad practice. Some papers are made blueish (to appear white) but I have found paper which is greenish, magentaish, yellowish, etc. while all appearing white to my eyes (wonderful thing how adaptive our eyes/brain are/is).

Maybe another question would be how to whitebalance. Putting it in a different place, slightly different angle, changed lighting etc. can all generate different results.

[stewarthemley]

Hi Yair
Thanks for the suggestion. Yes, enlarging the picker helps slightly, say in Photoshop, but 1) I can’t see how to do this in Phocus (only been using it 3 years!) and I suspect you can’t, and 2) It’s a problem with the grey card itself and causes problems with all the cameras/software I use. Maybe I should change to Leaf!

Hi Frank, Dustback and KLaven,
Agree, paper/clothes are not the best as a reference. I’m surprised about the possibility of coatings for softboxes causing problems though. I’d have thought that standard flash temps (5000?) were a basic requirement. But whenever I use flash I don’t usually have a need for apparently accurate colour.
In fact, up until lately, I’ve been happy to give my version of what looks good and nobody has yet even mentioned colour as a problem. The only time I have needed “accurate” colour is when copying an artist’s work. But I’ve got round that by having the paintings, not too large fortunately, in the same room as the monitor and managed to get acceptably close. Can’t manage that with buildings!

It’s something I’ve bumbled along with but for some deep psychological reason, would suddenly like more control over. Hmm. Time for alcohol.

Hi Secondfocus
Your assistant looks like I feel at the end of a shoot - just a hint of "high"! (No offense intended - I look much worse).

Dustback - good suggestion re white balance methods. I'll start it now.

Thanks again guys.

[Frank Doorhof]

Actually it's easy to explain about the strobes.
The light itself has a color temp indeed, but when it travels through the material it will be changed.
Especialy smokers will have that problem, I've seen soft boxes that are almost yellow.
I don't smoke and I. My studio it's prohibited to smoke it keeps my soft boxes nice and originally.

However when you wash the diffused material it could very well be a little cooler after the wash, simply because there are whiteners in the washing powder adding blue to the white.

Best would probably be to wash if needed just with normal water.

[Dustbak]

I recall from the Leaf capture software you could set the number of pixels the picker should use to come to a measure. Flexcolor was able to do the same. This is not (yet) in Phocus.

You can also enlarge the image when picking for whitebalance.

I guess because of irregularities in the cards light gets reflected differently in different places causing different measures as well.

[yaya]

Also if you have any colour noise in your image and you pick a spot that had Blue/ Yellow/ Magenta/ Green noise in it it'll give different results. This is where a larger picker radius helps

Yair