fluorescent lights

Discussion in 'Digital Photography' started by RichD, Sep 19, 2012.

  1. RichD

    RichD Guest

    I have to do some camera work under indoor
    fluorescent light. It's bright, no flash needed,
    but I'd like to know what adjustments to
    ameliorate color distortion.


    --
    RIch
     
    RichD, Sep 19, 2012
    #1
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  2. RichD

    Martin Brown Guest

    On 19/09/2012 20:30, RichD wrote:
    > I have to do some camera work under indoor
    > fluorescent light. It's bright, no flash needed,
    > but I'd like to know what adjustments to
    > ameliorate color distortion.


    Depends what you are photographing but you can get standard filters that
    roughly correct fluorescent light to approximately daylight.

    Mostly the problem comes from too much green so digitally a tweak of the
    green channel and auto white balance will get you something like.

    --
    Regards,
    Martin Brown
     
    Martin Brown, Sep 19, 2012
    #2
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  3. RichD

    Mort Guest

    Eric Stevens wrote:
    > On Wed, 19 Sep 2012 12:30:51 -0700 (PDT), RichD
    > <> wrote:
    >
    >> I have to do some camera work under indoor
    >> fluorescent light. It's bright, no flash needed,
    >> but I'd like to know what adjustments to
    >> ameliorate color distortion.

    >
    > The problem is that no specific light spectra are associated with all
    > fluorescent lamps. They vary from make to make: many manufacurers
    > offer several different types and they all can suffer from changes as
    > they age. See http://en.wikipedia.org/wiki/Fluorescent_lamp
    >
    > "Color rendering index (CRI) is a measure of how well colors can be
    > perceived using light from a source, relative to light from a
    > reference source such as daylight or a blackbody of the same color
    > temperature. By definition, an incandescent lamp has a CRI of 100.
    > Real-life fluorescent tubes achieve CRIs of anywhere from 50 to 99.
    > Fluorescent lamps with low CRI have phosphors that emit too little
    > red light. Skin appears less pink, and hence "unhealthy" compared
    > with incandescent lighting. Colored objects appear muted. For
    > example, a low CRI 6800 K halophosphate tube (an extreme example)
    > will make reds appear dull red or even brown. Since the eye is
    > relatively less efficient at detecting red light, an improvement in
    > color rendering index, with increased energy in the red part of the
    > spectrum, may reduce the overall luminous efficacy.[19]
    >
    > Lighting arrangements use fluorescent tubes in an assortment of
    > tints of white. Sometimes[weasel words] this is because of the lack
    > of appreciation for the difference or importance of differing tube
    > types.[citation needed] Mixing tube types within fittings can
    > improve the color reproduction of lower quality tubes.
    >
    > Depending on your camera, you may get fairly close to a good
    > adjustment. Otherwise you have to deal with it in post processing.
    >
    > It can't be too difficult. You are not the first person to be faced
    > with this problem. :)
    >

    Hi,

    Some cameras have built-in fluorescent tube correction factors that can
    be turned on. Take test pix with the various correction factors, then
    see which please you.

    Mort Linder
     
    Mort, Sep 19, 2012
    #3
  4. RichD <> writes:

    > I have to do some camera work under indoor
    > fluorescent light. It's bright, no flash needed,
    > but I'd like to know what adjustments to
    > ameliorate color distortion.


    Some modern cameras have seven different "fluorescent" white-balance
    presets. But if color is important, then I *strongly* suggest you just
    set a custom white-balance. That will take care of the cases where the
    lights in use don't exactly match any of your presets, and will do about
    the best possible with the case where the lights don't actually all give
    out the same color (different brands of bulbs and such).

    Also, shoot raw, so you can sort it out later if you absolutely have
    to. But doing a white balance in the camera is going to help in that
    situation, so do that even if you're shooting raw.
    --
    Googleproofaddress(account:dd-b provider:dd-b domain:net)
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Sep 19, 2012
    #4
  5. Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:
    > On 2012-09-19 14:25:23 -0700, Mort <> said:
    >> Eric Stevens wrote:
    >>> On Wed, 19 Sep 2012 12:30:51 -0700 (PDT), RichD


    >>>> I have to do some camera work under indoor
    >>>> fluorescent light. It's bright, no flash needed,
    >>>> but I'd like to know what adjustments to
    >>>> ameliorate color distortion.

    [...]
    >> Some cameras have built-in fluorescent tube correction factors that can
    >> be turned on. Take test pix with the various correction factors, then
    >> see which please you.


    > Better; Shoot RAW. Adjust WB temperature and tint/hue in ACR.


    > Best; Shoot a RAW calibration/reference shot with a WhiBal card under
    > the Fluorescent light. Set WB in ACR.
    > < http://michaeltapesdesign.com/whibal.html >
    > Take a look at some of the videos.


    That's not best.

    If the fluorescent light is weak in some colours, but not in
    the sum of all colours as seen by the broadband filters of
    the camera, your white balance card will show OK.

    "Best" would be to shoot a colour calibration target
    and use that to create a camera+light(+lens+ISO+contrast
    curve+saturation+...) specific profile, which you then use to
    correct the "wrong" colours out of your camera into the colours
    as they should be in sunlight (or whatever light situation you'd
    like to emulate).

    One such system (with limitations) was
    http://www.nexi.com/239
    for Bibble 4.

    -Wolfgang
     
    Wolfgang Weisselberg, Sep 20, 2012
    #5
  6. RichD

    Paul Ciszek Guest

    In article <>,
    RichD <> wrote:
    >I have to do some camera work under indoor
    >fluorescent light. It's bright, no flash needed,
    >but I'd like to know what adjustments to
    >ameliorate color distortion.


    What happens if you shoot under fluorescent lights with a shutter speed
    faster than 1/100 of a second? Wouldn't the flicker of the lights do
    weird things to exposure?

    --
    "Remember when teachers, public employees, Planned Parenthood, NPR and PBS
    crashed the stock market, wiped out half of our 401Ks, took trillions in
    TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
    bonuses, and paid no taxes? Yeah, me neither."
     
    Paul Ciszek, Sep 20, 2012
    #6
  7. Paul Ciszek <> wrote:

    > In article <>,
    > RichD <> wrote:
    >>I have to do some camera work under indoor
    >>fluorescent light. It's bright, no flash needed,
    >>but I'd like to know what adjustments to
    >>ameliorate color distortion.


    > What happens if you shoot under fluorescent lights with a shutter speed
    > faster than 1/100 of a second? Wouldn't the flicker of the lights do
    > weird things to exposure?


    It might do. It might also do odd things to the white balance. Best to
    experiment on site.

    --
    Chris Malcolm
     
    Chris Malcolm, Sep 21, 2012
    #7
  8. (Paul Ciszek) writes:

    > In article <>,
    > RichD <> wrote:
    >>I have to do some camera work under indoor
    >>fluorescent light. It's bright, no flash needed,
    >>but I'd like to know what adjustments to
    >>ameliorate color distortion.

    >
    > What happens if you shoot under fluorescent lights with a shutter speed
    > faster than 1/100 of a second? Wouldn't the flicker of the lights do
    > weird things to exposure?


    Modern fluourescents have electronic ballasts, which drive the lights at
    something like 40,000 Hz, so the flicker won't show photographically.
    This includes all compact fluourescent bulbs, and modern long-tube
    fixtures.

    The old, simple ballasts (the only kind around in the 1960s; not sure
    when or how fast the changeover happened, but you can still buy the
    bulbs for that type) simply used the power-line frequency so in the USA
    the bulbs flickered at 120 Hz, which some people could see and which you
    COULD catch at a bad level in a photograph.

    --
    Googleproofaddress(account:dd-b provider:dd-b domain:net)
    Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
    Photos: http://dd-b.net/photography/gallery/
    Dragaera: http://dragaera.info
     
    David Dyer-Bennet, Sep 22, 2012
    #8
  9. Alan Browne <> wrote:
    > On 2012.09.20 15:12 , Paul Ciszek wrote:
    >> RichD <> wrote:


    >>> I have to do some camera work under indoor
    >>> fluorescent light. It's bright, no flash needed,
    >>> but I'd like to know what adjustments to
    >>> ameliorate color distortion.


    >> What happens if you shoot under fluorescent lights with a shutter speed
    >> faster than 1/100 of a second? Wouldn't the flicker of the lights do
    >> weird things to exposure?


    > It may.


    > I just shot about 10 frames at 1/400 using a CF as illumination. All
    > the exposures were the same. I'm not sure what the mechanism is - it
    > could simply be that the "extinguish" decay is too slow.


    Nope. You've simply got fluorescent lights that simply flicker
    way faster (a 20k, 30k, 40k Hz) than with the 50 or 60 Hz net
    frequency.
    https://en.wikipedia.org/wiki/Electrical_ballast#Electronic_ballasts_.28digital_ballast.29

    > Even the in-camera metering got it right (enough).


    > But with other lights (larger separate ballast lights) there may be a
    > difference. It pays to test before the talent arrives.


    Yep, some lights may be bad there; especially with net frequency
    and short exposure times you may well get bad colour shifts as
    the phospors fade with different speeds.

    -Wolfgang
     
    Wolfgang Weisselberg, Sep 22, 2012
    #9
  10. Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:
    > On 2012-09-20 09:12:40 -0700, Wolfgang Weisselberg
    >> Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:


    >>> Better; Shoot RAW. Adjust WB temperature and tint/hue in ACR.


    >>> Best; Shoot a RAW calibration/reference shot with a WhiBal card under
    >>> the Fluorescent light. Set WB in ACR.
    >>> < http://michaeltapesdesign.com/whibal.html >
    >>> Take a look at some of the videos.


    >> That's not best.


    > In my World, since I actually have a WhiBal Card with me, it is best.


    In other peoples' Worlds, shooting RAW is best, then!


    >> If the fluorescent light is weak in some colours, but not in
    >> the sum of all colours as seen by the broadband filters of
    >> the camera, your white balance card will show OK.


    > You didn't look at any of the videos did you?


    Does the card have colour fields? No? Then I don't need to
    look at the videos to know it can ONLY do white balance.


    > What do you mean, "your white balance card will show OK"?


    "seem white/gray, e.g. under the colour picker, even though
    some colours are very weak or overly strong in the light."


    > The WhiBal card is not going to "show" anything. It is going to be
    > present in the reference shot, under the light in the shooting
    > environment. Then it is used as a target for setting the WB in ACR or
    > whatever SW you are using for RAW processing.


    It's as good as calibrating a monitor simply on a single gray patch.


    >> "Best" would be to shoot a colour calibration target
    >> and use that to create a camera+light(+lens+ISO+contrast
    >> curve+saturation+...) specific profile, which you then use to
    >> correct the "wrong" colours out of your camera into the colours
    >> as they should be in sunlight (or whatever light situation you'd
    >> like to emulate).


    > Perhaps, perhaps not.


    Not only perhaps.


    >> One such system (with limitations) was
    >> http://www.nexi.com/239
    >> for Bibble 4.


    > In that case, perhaps not, since I do not use Bibble 4, and the
    > installed ClairePRO plug-in, and I don't happen to have a Gretag Mabeth
    > ColorChecker handy.


    You could use
    http://www.qpcard.com/

    Or use the info from
    http://staffwww.itn.liu.se/~karlu/div/howto/qpcard201_argyll.php
    to do that with any colour card, most RAW converters and
    argylcms.

    > Therefore for me, using a WhiBal card, and a reference shot to set the
    > WB for the batch of shots shot under the same light, is the best
    > solution. It fixes 99% of the WB+colorcast problems without becoming
    > too anal over the problem.


    99%? No way. With basically black body emitters with some green
    or magenta filter it works. The more the light source diverges
    from that (fluorescent lights come to mind), the more some colours
    will be off. Of course, if you only shoot in daylight or
    with RA 98 or better lights ...

    -Wolfgang
     
    Wolfgang Weisselberg, Sep 22, 2012
    #10
  11. RichD

    gregz Guest

    Paul Ciszek <> wrote:
    > In article <>,
    > RichD <> wrote:
    >> I have to do some camera work under indoor
    >> fluorescent light. It's bright, no flash needed,
    >> but I'd like to know what adjustments to
    >> ameliorate color distortion.

    >
    > What happens if you shoot under fluorescent lights with a shutter speed
    > faster than 1/100 of a second? Wouldn't the flicker of the lights do
    > weird things to exposure?



    They change levels more than tungsten lamps, but the phosphor has
    persistence, which limits decay.

    Greg
     
    gregz, Sep 23, 2012
    #11
  12. Savageduck <savageduck1@{removespam}me.com> wrote:
    > On 2012-09-20 09:12:40 -0700, Wolfgang Weisselberg
    > <> said:
    >> Savageduck <savageduck1@{REMOVESPAM}me.com> wrote:
    >>> On 2012-09-19 14:25:23 -0700, Mort <> said:
    >>>> Eric Stevens wrote:
    >>>>> On Wed, 19 Sep 2012 12:30:51 -0700 (PDT), RichD

    >>
    >>>>>> I have to do some camera work under indoor
    >>>>>> fluorescent light. It's bright, no flash needed,
    >>>>>> but I'd like to know what adjustments to
    >>>>>> ameliorate color distortion.

    >> [...]
    >>>> Some cameras have built-in fluorescent tube correction factors that can
    >>>> be turned on. Take test pix with the various correction factors, then
    >>>> see which please you.

    >>
    >>> Better; Shoot RAW. Adjust WB temperature and tint/hue in ACR.

    >>
    >>> Best; Shoot a RAW calibration/reference shot with a WhiBal card under
    >>> the Fluorescent light. Set WB in ACR.
    >>> < http://michaeltapesdesign.com/whibal.html >
    >>> Take a look at some of the videos.

    >>
    >> That's not best.


    > In my World, since I actually have a WhiBal Card with me, it is best.
    >>
    >> If the fluorescent light is weak in some colours, but not in
    >> the sum of all colours as seen by the broadband filters of
    >> the camera, your white balance card will show OK.


    > You didn't look at any of the videos did you?
    > What do you mean, "your white balance card will show OK"?


    > The WhiBal card is not going to "show" anything. It is going to be
    > present in the reference shot, under the light in the shooting
    > environment. Then it is used as a target for setting the WB in ACR or
    > whatever SW you are using for RAW processing.


    >> "Best" would be to shoot a colour calibration target
    >> and use that to create a camera+light(+lens+ISO+contrast
    >> curve+saturation+...) specific profile, which you then use to
    >> correct the "wrong" colours out of your camera into the colours
    >> as they should be in sunlight (or whatever light situation you'd
    >> like to emulate).


    > Perhaps, perhaps not.


    >>
    >> One such system (with limitations) was
    >> http://www.nexi.com/239
    >> for Bibble 4.
    >>
    >> -Wolfgang


    > In that case, perhaps not, since I do not use Bibble 4, and the
    > installed ClairePRO plug-in, and I don't happen to have a Gretag Mabeth
    > ColorChecker handy.


    > Therefore for me, using a WhiBal card, and a reference shot to set the
    > WB for the batch of shots shot under the same light, is the best
    > solution. It fixes 99% of the WB+colorcast problems without becoming
    > too anal over the problem.


    Now and then I like exploring a photographic problem in as much detail
    as I can manage with the kit to hand or not too difficult or expensive
    to acquire. That's what gives me the skills to improve the technical
    image quality I can coax out of the kit I have, or be able to get
    shots of acceptable quality in very difficult conditions.

    I'm impressed by how often the camera's auto white balance gets it
    good enough, which I guess is 95% of the time. I guess a white balance
    card used to set the camera's white balance covers 99%. The problem is
    that seriously anal colour accuracy is quite often what is required in
    a paying shoot, such as photographing a painting for an artist's or
    gallery's portfolio. It might be why they're paying me to do the shot
    rather use their iPhone or ask their friend with the big expensive
    camera.

    That's why I've now started keeping a Gretag Macbeth colour chart
    handy in my gear bag. I'm not yet using it to do the tedious process
    of setting up colour profiles. I just bung it into a shot when I'm
    curious about possible colour problems. Data collection. There's an
    interesting residuum of special cases where the white balance is spot
    on, but some of the colours quite definitely aren't. Clearly there is
    sometimes more than one solution to the problem of getting the white
    balance card to to be white in the camera image.

    --
    Chris Malcolm
     
    Chris Malcolm, Sep 26, 2012
    #12
  13. Chris Malcolm <> wrote:
    > Savageduck <savageduck1@{removespam}me.com> wrote:
    >> On 2012-09-20 09:12:40 -0700, Wolfgang Weisselberg


    >>> "Best" would be to shoot a colour calibration target
    >>> and use that to create a camera+light(+lens+ISO+contrast
    >>> curve+saturation+...) specific profile, which you then use to
    >>> correct the "wrong" colours out of your camera into the colours
    >>> as they should be in sunlight (or whatever light situation you'd
    >>> like to emulate).

    [...]
    >>> One such system (with limitations) was
    >>> http://www.nexi.com/239
    >>> for Bibble 4.

    [...]
    >> Therefore for me, using a WhiBal card, and a reference shot to set the
    >> WB for the batch of shots shot under the same light, is the best
    >> solution. It fixes 99% of the WB+colorcast problems without becoming
    >> too anal over the problem.


    [...]
    > I'm impressed by how often the camera's auto white balance gets it
    > good enough, which I guess is 95% of the time.


    Good enough for what?

    There's a difference between "it looks OK", "it looks
    realistic" and "it's as exact a copy as one can make it,
    colourwise included".

    > I guess a white balance
    > card used to set the camera's white balance covers 99%.


    Hmmm ... the "looks OK" part, yes. Which often *is* enough.

    > The problem is
    > that seriously anal colour accuracy is quite often what is required in
    > a paying shoot, such as photographing a painting for an artist's or
    > gallery's portfolio. It might be why they're paying me to do the shot
    > rather use their iPhone or ask their friend with the big expensive
    > camera.


    Maybe ...

    > That's why I've now started keeping a Gretag Macbeth colour chart
    > handy in my gear bag. I'm not yet using it to do the tedious process
    > of setting up colour profiles. I just bung it into a shot when I'm
    > curious about possible colour problems. Data collection. There's an
    > interesting residuum of special cases where the white balance is spot
    > on, but some of the colours quite definitely aren't. Clearly there is
    > sometimes more than one solution to the problem of getting the white
    > balance card to to be white in the camera image.


    Yep. WB can only boost really broad swaths of colour: the red
    sensor filter's curve, the green and/or the blue one.

    -Wolfgang
     
    Wolfgang Weisselberg, Sep 26, 2012
    #13
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