Getting whites white

htid

htid

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Chris
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Hi,

For our company we've bought a small studio setup to take photos of our products. We have 2 x 200w flashes, 1 with an umbrella and one with a softbox. We set the products on a small product photography table bought from lencarta. The whole thing is in a warehouse with no natural light, but some ambient light from the tube lights in the warehouse (I've removed the ones which are directly overhead). The trouble is, the whites aren't always perfectly white...is this because I'm using the wrong exposure, or is it because I'm not using a grey card? I have the WB set to 'flash' on my camera (although I haven't changed the temperature or whatever). I then have to change them all a bit in post, which is quite annoying. Is this what a grey card is for? If we buy one, will it give me the results I'm looking for, or would I still have to tinker in post to get the whites a nice white?

Thanks for any help!
 
Yes, a grey card will help.

Two basic ways of using it, which one you choose depends on how you post-process to some extent.

1) Use the Grey Card to set up a custom white balance at the start of your shoot. This will then apply to all shots. (I am assuming here that the D7000 can set this up in a similar manner to my A700).

2) Shoot in RAW, take a shot of the grey card as the first shot in the sequence.
In PP, use the grey card to set the WB for the first shot, then apply that to all shots in the sequence.
 
htid said:
I have the WB set to 'flash' on my camera (although I haven't changed the temperature or whatever). I then have to change them all a bit in post, which is quite annoying.
Click to expand...

According to Nikon the 'flash' option in the WB menu is 5400K (p117 in manual) so to reproduce colours accurately the colour temp of the studio flashes (Lencarta?) would also need to be 5400K. The colour temp of the studio flashes will vary on different power settings so even if they are 5400k at full power they won't be 5400K at say 1/8th power (see http://www.lencarta.com/faq/colour-temperature). The answer is to use Preset Manual WB (or PRE *) and something like a Lastolite Ezybalance as in post 3.

* Preset Manual - see p123 in D7000 manual.
 
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What is your shutter speed? It must be as high as possible or you'll get ambient light affecting things, but no higher than max x-sync speed. If in doubt (using radio triggers?) use 1/125sec.

The pre-set white balance options should get you close, but the exact colour of the light depends on a) the flash, b) the exact colour of the umbrella/softbox, c) any slight colour picked up from light reflected off nearby objects/walls (most likely contributor).

The fluorescent tubes are unlikely to have any effect, they will be so overwhelmed by the flash. Test this by taking a shot as you would normally but with the flash switched off. If it is very dark, even black, you're okay - it will be if the shutter speed is set as above.

The answer is a custom white balance - see handbook. A sheet of white paper is fine - normal copier paper will not be far out, if not perfect. Get a white balance card if you like, but be aware that some 18% grey cards are for exposure, not white balance, and are not neutral.

Various other ways you can get it exact, but if your shutter speed is right and you've done a custom balance correctly from a piece of plain white paper, it will be extremely close if not spot on. Try that first.
 
Chris Primadona said:
I can't use "flash" wb settings for my lights, always turn out a bit of blue that way, Auto is spot on for me, but I also shoot raw anyway.
Click to expand...

AWB will not work with studio lights, it will attempt to balance the ambient. AWB for flash only works with a dedicated E-TTL gun.
 
Yes, to get your whites properly white you will always need a reference... but for product photography, don't just get your whites right white (...:nuts:...) but get your colours right as well.

Simplest thing to do everything is to get an X-Rite Passport its dead easy to use and won't add any significant amount of time as you only need to do it once per session, or probably even less if nothing much changes...
 
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