Natural light isn’t white

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This topic contains 9 replies, has 4 voices, and was last updated by Profile photo of Ian McNab Ian McNab 3 weeks, 2 days ago.

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  • #15255
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    Photograph the bride outside the church on a sunny afternoon with a clear blue sky. Set your camera to auto white balance, and it will try to recalculate the colours in your picture with all the clever maths that its micro computer can whiz through while you’re still lifting your finger off the shutter release, in an effort to make bride’s dress look white.

    Unfortunately, the result will not be how your eyes saw the colours in the scene, because the sunlight and the light from the blue sky are not white, so the white dress didn’t actually look white to your eyes: that’s just the colour your brain ‘knows’ a wedding dress ought to be. In fact, if the bride was standing in the sun, the light bouncing off the dress will be anything from pale-straw coloured to golden. And if she was standing in the shade of the porch, it’ll be one of a subtle range of paler or deeper blues.

    The same issues about colour come up even more obviously with photographs done in the evening in a brightly lit street full of shops, or at night by an open window in a room lit with table lamps. But those are times when you’d use flash, right?

    Well, the flash built into your camera, or the one you attach to it, are designed to produce white light. So your picture with flash in the evening street or the lamp-lit room will look unnatural – as if lit with flash, even if you turn down the flash power and slow the shutter to let the ambient light affect the picture. Because the cold white light your flash puts into the scene wouldn’t naturally be there, so it isn’t what your mind unconsciously expects. (And if you use fill flash on our poor old bride outside the church on that sunny afternoon, she’ll look oddly unnatural, too, for the same reasons: the colour of the light isn’t what would naturally be there.)

    The trick with using the natural light to photograph scene outside the church is to start off with the camera’s white balance set to Daylight. At least that’ll give you something near the colour of the light you’re actually seeing. But what to do with the unnaturally white light of your flash?

    Well, that’s the subject of the third section of a three-part course on lighting that internationally renowned photographer and lighting expert, David Hobby – known generally as the ‘Strobist’ – has been publishing for free on his blog over the last few years. This final section – ‘Lighting 103’ – is all about colour; and David has just finished it with a summary, that gives you an idea of what’s covered.

    If you want to learn more about this topic, an outline of the pre-requisites and equipment you need is here; and the course itself starts here. (If you are just beginning with lighting, work through the first two sections of the course, Lighting 101 and Lighting 102, which you can find via the drop-down archive menu at the bottom of the little block of notices on the right of any of the pages on David’s blog.)

    Photographers have to work at getting colour right – it’s not just a matter of leaving it to what happens to turn up in front of our lenses and what the programmers who wrote the software for our digital cameras guessed would usually be OK. (Of course, the other option is to stick to monochrome, which brings its own set of photographic problems, but gets you off the difficult one of also working with colour!)

    #15256
    Profile photo of KEN LAST
    KEN LAST
    Participant

    All so well explained Ian as always. The human brain works wonders letting us see what we think we should be seeing. Thinking back on all of those weddings I photographed on film and questionable processing , the brides mothers were not short of something to moan about–but never once about the whiteness of the dress. Yet bet if we could now review the photo”s  it would be obvious.———You will know this  Ian but a little conundrum for readers. Take a tripod time exposure outside in full bright moonlight—-and how will the colours appear with all settings on daylight?????

    #15257
    Profile photo of Peter Robinson
    Peter Robinson
    Keymaster

    Thanks for posting this Ian. I had a quick look at the articles and they make interesting reading about something most people wouldn’t consider. It’s always a bit of a nightmare and compromise  photographing in mixed lighting. I’ve tried photographing bands where the light constantly changes colour and intensity. You just can’t record the colours as you saw them. Some people recommend photographing a grey card before you photograph take a batch of photos in the same light source. You can then balance the colour in your processing software and use that balance for the other pictures. That’s not guaranteed to work, but it give you a start. Like you say often an artificially warmed photograph can look more attractive. It’s a big topic.

    #15265
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    It’s always a bit of a nightmare and compromise photographing in mixed lighting. I’ve tried photographing bands where the light constantly changes colour and intensity. You just can’t record the colours as you saw them.

    That hit’s the nail on the head exactly: the camera doesn’t record the colours as you saw them – it records the frequencies of the light that hits the sensor; but the colours we perceive in real scenes are constructed by our brains from what our eyes detect, heavily modified by our knowledge of what colour the things actually are. In other words, our perception cleverly ‘corrects’ for the lighting. Cognitive psychologists call this ‘colour constancy’: we really do perceive the bride’s dress as white, regardless (within limits) of the colour of the light illuminating it, whether it’s sunlight, moonlight, firelight, fluorescent bulbs, or whatever.

    This problem is exacerbated in mixed lighting because our cameras record the colours literally, so they look odd to us. And if we try to adjust the colour balance in post processing, we can’t please the girl who has carefully chosen a ‘Cadbury’s Purple’ hue for her dress without making her face sickly green under the fluorescent lighting; and if we put her skin tones right, she’s annoyed because we’ve made her dress look royal blue!

    Really, the only way to deal with this is to take complete control of the lighting, which is how those geniuses of light, the film makers (i.e cinematographers and lighting designers) do it so that we don’t even notice.

    Here, cinematographer Roger Deakins, describes his lighting set up for a single location scene from the 2016 Coen Brothers film, ‘Hail, Caesar’:

     

     

    “This scene was shot on location and, although a seemingly simple scene, this caused quite a few challenges. Not the least of these was controlling the natural light during daylight hours and into the evening. The location windows were facing South West, which made control of the sun even more critical. To do this I decided to light with large Ultrabounce reflectors. Using these, it is possible to cut out any natural light whilst re-creating the softness of north facing daylight.

    “I also wanted to build in some colour contrast and pretend there was a warm overhead source. This was in fact a soft box of 4 bouncing Nook lights, all of which were dimmed down to produce the warmth in the scene. The whole rig was suspended from existing ceiling light fittings and, consequently, needed to be as lightweight as it could possible be without compromising its soft quality.”

    And here’s Deakins’s lighting plan:

    This is exactly why David Hobby says that photographers who photograph in colour should not use bare, ungelled flash!

     

     

    #15269
    Profile photo of John Royle
    ajroyle
    Keymaster

    I put a link to a You Tube video on the front page about using colouration a little while back – here.

    #15271
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    Interesting video, John: we either consciously create a colour palette, or we let the world dump one on us arbitrarily.

    It reminds us, if we needed reminding, that colour in photographs is as much an ‘artificial’ set of conventions and decisions as monochrome is. Neither is ‘real’ or ‘natural’; both are about design and about solving interesting ‘picture problems’ that we set ourselves as photographers.

    #15273
    Profile photo of KEN LAST
    KEN LAST
    Participant

    Before looking back–what is the colour of the snow mountain  in Ralph Browes superb front page photo???

    #15274
    Profile photo of John Royle
    ajroyle
    Keymaster

    Good point. Blue.

    Now I’ve looked it is the blue sky which perhaps influenced my memory. Perhaps the snow is grey-blue.

     

    #15278
    Profile photo of KEN LAST
    KEN LAST
    Participant

    Such an important and interesting subject Ian opened with this. If Ralph will excuse me for using his snow mountain photo, this is a good example to explore. Now in the good old days we would have used a UV filter and more likely a light pink UV filter for the mountain scene so as to reduce the blue. Would anyone do this with digital???  I have experimented on the photo, but will not post as I have not sought permission. But   de- saturate the  light blue and a little tad of dark blue in PS  and just look how the snow is more natural. But see how the rocks and the climbers have the blue eliminated and become so natural. The blue hats stand out so well.  Think in these conditions the white balance could be set to reduce blue.

    #15293
    Profile photo of Ian McNab
    Ian McNab
    Keymaster

    I’ve just posted the following comment on the Monthly Theme forum, where our discussion here seems to have leaked. But my comment needs to be here, too, for completeness…

    The blue in Ralph’s picture could possibly be a bit more intense than the blue shade you’d actually see (perhaps because he has toned down the highlights to reduce some ‘glare’ from the snow on the mountain in the background? Such adjustments tend to shift hue values, too.)

    But it is certainly the case that shadows on snow on a bright day actually do look blue-ish, because of the colour reflected faintly from a blue sky. So ‘fixing’ that blueness with white balance or other tonal adjustments actually makes such shaded areas look less natural (though it may, of course, create a picture that’s warmer, if that’s the look you want to fabricate).

    That was the whole point of the original post here: natural light isn’t white.

     

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