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Thread: Grey Cards

  1. #1

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    Grey Cards

    I have a question concerning grey cards. For the WB do you have to use custom or does it matter?

    Thanks,

    Renee'

  2. #2

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    Re: Grey Cards

    Hi Renee',

    It all depends on how you're shooting.

    If you're shooting RAW then the white balance can easily be adjusted later in post-production - so it doesn't matter what it's set to in the camera. It DOES help to have what's called a "spectrally neutral" reference in a shot though (ie something that's truly white or grey.

    If you're shooting JPEGs then you can either set a custom white balance using a grey card (or other spectrally neutral reference) (in which case no further adjustments are needed) - or you can again adjust the images later in post-production (possibly losing a little information in the process) (although usually not visually obvious).

    If the camera is set to anything other than custom WB then it'll just use whatever it's set to.

  3. #3

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    Re: Grey Cards

    Hi Renee,

    On my Nikon it is called Pre-Set WB. A piece of pure white or neutral grey paper is held in front of the lens and the WB button is pressed until Pre-Set flickers, then you press the shutter button and the WB is set. In "Custom" it would mean setting the WB to a specific Kelvin Temp.
    If you use Auto WB you do not have to worry about "Grey cards".
    Shooting under artificial light the Auto WB does not always render the correct WB, therefore a custom or pre-set WB feature is build in to get it right - if you do not want to do PP you are bound to learn how to use these features.

    If you shoot a sunset with WB on Auto the camera compensates for the orange tint and you do not get those rich colours in the image. Setting the WB to custom, depending on the kelvin setting, you are going to either get the scene to be richer and warmer or cooler. On custom WB you can control how warm or cool you want the scene to be.

    "For the WB do you have to use custom?" NO! It is up to you to decide.

  4. #4
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    Re: Grey Cards

    I always shoot in RAW with auto WB and take care of the WB in post processing. Mostly in daylight, the auto WB is spot on! However, indoors, I try to use a WB reference. The WhiBal card is the most accurate that I have used. However, if I were going to aim for the most correct white balance, I would also want to make sure that my monitor is calibrated...

    Note: as has been remarked on in earlier posts, "correct" white balance is not always the most pleasing. In fact, I tend to lean a bit toward warner WB when I am shooting people.

  5. #5

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    Re: Grey Cards

    OK Thanks to all that have replied to my question!! I do shoot in RAW have just started using about 4 months ago. I have been watching Learn & Master Photography w/ Vince Wallace and learned from him how important it is to shoot in RAW.

    Renee'

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    William W's Avatar
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    Re: Grey Cards

    I have (neutral) Photographic Grey Cards and also the WhiBal Set of cards which Richard mentioned – and I often use neither and just use AWB. I always shoot ’raw + JPEG(L)’.

    The point I wish to make is:

    IF I have gone to the effort to pull it out and use a Grey Card (for either White Balance OR Exposure) – then I will usually also shoot the Grey Card somewhere in the first frame - for example for Potraiture the Subject will hold it at waist level.

    This frame can be used as a reference frame for that particular series, which can be very useful in Post Production.

    WW

  7. #7
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    Re: Grey Cards

    I find it extremely helpful to have a good gray card (I use a small whiBal) when I am uncertain about white balance. Shoot one frame with the card in every lighting condition, and you have a good reference for setting WB in postprocessing (or, at least, a good starting point).

    However, it is essential to have something that is truly spectrally neutral reference.

    A piece of pure white or neutral grey paper is held in front of the lens and the WB button is pressed until Pre-Set flickers,
    White paper, or other white things, just does not cut it. Try a few different papers and compare the results. I did this by accident during the short time I shot jpeg. I wanted to set a custom WB to use for halogen lighting. I put a piece of white paper on a white tile table, and I found that I got substantially different WB from the two. One was much bluer than the other. Even high quality photo papers differ--those with more optical brighteners are far less yellow than others.

  8. #8
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    Re: Grey Cards

    "White" paper is often not exactly white! Very often it contains a bluing agent to make it look whiter. This may throw off white balance. The WhiBal card has been tested to be neutral in color. The small ones (G-7) are twenty dollars on the B&H website with free shipping. The card is neither white nor gray but. works great!

    At first I balked at spending twenty bucks for a piece of plastic. However, I have spent thousands on my photo equipment and consider twenty bucks as a small amount to spend to attain the best images.

    I am not sure about the "keychain" Whibal unit. It seems like carrying it in my pocket with my keys and coins might scratch it or otherwise hurt its integity.

  9. #9

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    Re: Grey Cards

    I use a WB reference made by Robin Myers Imaging called the Digital Gray Card. It's a 4" x 6" plastic reference that's 3mm thick, so it's pretty sturdy. Fits perfectly in my back pocket. Of course, it's spectrally neutral, but it also has an excellent matte surface that improves the WB setting by minimizing any specular reflection. It's so good that I can set on a table with a light overhead, spot meter the card with the camera, and the meter reading won't change from directly overhead to about 70 degrees off vertical. RMI says that if it gets dirty all you have to do is sand it to renew the surface. The card is only 15 bucks, so it's the least expensive of the WB references that are known to be of good quality.

    I also use my DGC to set exposure. RMI says not to use them for exposure because they're something like 30% reflectance, but the matte surface is so well suited for exposure that I use it anyways. I just set +1.3 EC and I get standard exposure. So one card does double duty. Apparently, while the spectral neutrality of the card is guaranteed, the reflectance is not. So cards to be used for exposure need a quick "calibration" process to discover the appropriate compensation. But once you figure out the EC for your card, it works great.

    The question asked was a bit cryptic. The answer to the question itself, in isolation, is no. But in the context of a gray card, then the answer is yes, if you're trying to set the in-camera white balance using a gray card, then you must use the camera's custom WB process. I actually prefer to set a custom white balance every time I step into new light because 1. I always find it looks best, and 2. it's so easy with a Nikon. Of course, that's not for every image. Anytime the color of the light is an important element of the image, as with sunsets and candlelight, then I'll set Daylight WB. However, I don't like to use the WB setting to tone the image. If I want more red in the image, I'll use the color adjustment, where I can have far more control over how the tone is applied.

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    Re: Grey Cards

    Quote Originally Posted by William W View Post
    IF I have gone to the effort to pull it out and use a Grey Card (for either White Balance OR Exposure) – then I will usually also shoot the Grey Card somewhere in the first frame - for example for Potraiture the Subject will hold it at waist level.

    This frame can be used as a reference frame for that particular series, which can be very useful in Post Production.
    For sure! One of my greatest frustrations is trying to adjust white balance by eye (because I forgot to shoot a grey card) and suffering endless loops of "that doesn't look quite right" followed after an adjustment by "and that doesn't look right either".

    In the studio I can sometimes go back to previous settings (often 4800 / -7) but even with same lights - same soft boxes - same camera - same lens - it can STILL vary significantly ... still haven't figured that one out!

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    Re: Grey Cards

    Quote Originally Posted by rpcrowe View Post
    "White" paper is often not exactly white! Very often it contains a bluing agent to make it look whiter. This may throw off white balance.
    They often have UV fluorescers (sp?) (same for washing powder) so they can appear "whiter than white".

    The WhiBal card has been tested to be neutral in color.
    The other thing many people don't seem to realise is it's not just sufficient to be "neutral in colour", they need to be neutral in colour across a wide range of colour temperatures - and THAT's the "trick". Case in point ... my 1Ds3 is basically black - the RRS bracket is basically black too. Under fluorescent lights both look black - under incandescent lights the camera body is still black but the bracket is quite obviously purple. Metamerism is alive and well

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    Re: Grey Cards

    Photo the back of your hand and add +1 EV. Here is an interesting article:

    http://www.clickinmoms.com/blog/colo...white-balance/

  13. #13
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    Re: Grey Cards

    Using the palm or the back of the Photographer’s Hand and opening up One Stop, is an ‘Handy’ ”Rule of Thumb” for METERING and / or getting the EXPOSURE close to correct - but I fail to reckon how it would get the White Balance Correct?

    Also when using this method as an Exposure Rule of Thumb - the following criteria are necessary:

    > the hand must be in the same lighting condition as the Subject or Scene.
    > the hand must be caucasian and with average sun tan and skin pallor.

    WW

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    Re: Grey Cards

    Quote Originally Posted by rambler4466 View Post
    Photo the back of your hand and add +1 EV. Here is an interesting article:
    That's for setting exposure, not white balancing.

    It was an interesting "primer", but I've got a couple of issues with it to be honest ...

    - For sure, white balance has an effect on grey scale conversions - but it has NO effect on exposure (of a RAW shot anyway). So whether it's set correctly or incorrectly, it isn't going to make any difference. Or put another way, the camera isn't going to adjust it's shutterspeed / ISO / aperture for a given scene depending on the WB you have set.

    - She talks about setting WB by kelvin ... frankly, most cameras will do this more accurately on just auto WB. The biggest problem with just using kelvin is that it's only an adjustment along the blue/yellow axis and won't correct for any shifts along the magenta/green axis (which is often beneficial with normal lighting and ABSOLUTELY ESSENTIAL with some types of artificial light).

  15. #15

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    Re: Grey Cards

    Quote Originally Posted by William W View Post
    Using the palm or the back of the Photographer’s Hand and opening up One Stop, is an ‘Handy’ ”Rule of Thumb” for METERING and / or getting the EXPOSURE close to correct - but I fail to reckon how it would get the White Balance Correct?
    'Mornin' Bill!

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    Re: Grey Cards

    Hi Colin.

    Great day here - the boss is calling me to clean the pool . . .

    Yes I read the extract I have concerns about what was sritten in that link about the Grey Scale Conversions, also - it was very scant - there are many nuances to GS Conversions.

    Also - hoepfully more later today from me - on a few other points on this thread.

  17. #17

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    Re: Grey Cards

    Quote Originally Posted by William W View Post
    Hi Colin.

    Great day here - the boss is calling me to clean the pool . . .
    You best get to it quickly then ... before all the water evaporates in the heat over there!

  18. #18
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    Re: Grey Cards

    Quote Originally Posted by Colin Southern View Post
    Under fluorescent lights both look black - under incandescent lights the camera body is still black but the bracket is quite obviously purple. Metamerism is alive and well
    We got that surprise when we remodeled our spare bathroom and painted it a nice green. I installed dimmable CFL bulbs and Oh My Gosh! That nice green color turned into a putrid ugly green. How could we have picked that color? Switched the bulbs back to incandescent and the green was once more "nice".
    Last edited by rpcrowe; 11th November 2012 at 12:33 AM.

  19. #19
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    Re: Grey Cards

    Well timed thread, I just bought a set of white, grey, and black cards.

  20. #20
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    Re: Grey Cards

    Quote Originally Posted by Colin Southern View Post

    - She talks about setting WB by kelvin ... frankly, most cameras will do this more accurately on just auto WB. The biggest problem with just using kelvin is that it's only an adjustment along the blue/yellow axis and won't correct for any shifts along the magenta/green axis (which is often beneficial with normal lighting and ABSOLUTELY ESSENTIAL with some types of artificial light).
    Needing to adjust the magenta/green axis indicates you have a problem. With the blue/yellow colour temperature axis you will often be lucky enough to be dealing with a black-body or incandescent light source that will have a reasonably continuous spectrum and a colour temperature adjustment should work fairly well. Unfortunately needing a magenta/green axis adjustment indicates you are dealing with a noncontinuous spectrum light source that will have a mix of bands of colour. It is unlikely you will be able to do an adjustment that will keep a true relationship between all the colours in an image. The WB compromise will inevitably be far greater with these light sources and may never be satisfactory. (The dress was not that colour - my handbag should match my scarf)

    In the field I leave the camera on Auto WB shoot RAW, concentrate on subject, exposure, focus and composition and then worry about the final colour correction later in the comfort of a chair. I think Colin and many others do the same.

    P.S. Take a flash illuminated photographs of the colours in the dress, handbag and scarf for reference/defensive use latter.

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