Softbox diffusers with clearly different colors

Discussion in 'Lighting and Hardware' started by Guille77, Aug 11, 2017.

  1. Guille77

    Guille77 TPF Noob!

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    This is my very first post in the forum, so as a very short presentation I'll say I'm a hobby photographer from Spain living in Germany, who learnt taking pictures with a Praktika reflex film camera about 25 years ago and retook the hobby around 5 years ago already in the digital era. I (re-)started with a Nikon d5200 and jumped to the d750 1,5 years ago.

    I've been trying to focus a bit more on portrait photography during the last 1-2 years. I've purchased some hardware for that, a couple of studio and system flashes, and some light modifiers - and that's where my question comes in.

    I've bought during the last months a few of very cheap softboxes from Jinbei, which happened to come with diffusers (I refer to the fabric you attach to the front of the softbox with velcro, just in case) of different tonality. Some are neutral white, while some others have a noticeably warmer, yellow-ish tone. I'm not talking about barely noticeable differences between different manufactures, I mean two clearly distinguishable colors from the same manufacturer. They could be perfectly sold separately, as a customizing option. But it just seems to be a matter of luck which one you get. I try to upload a pic...

    DSC_7207.JPG

    In order to avoid the pain of mixing light sources with different light temperatures, I'll return or sale some of them and only keep light modifiers with the same characteristics. But I'm not sure which ones I should keep. Some advice on the following questions would help me a lot:

    - Is it also normal for other manufacturers to have diffusers which are clearly warmer than neutral white? What's more common?

    - If that's the case, do you have any preferences? I could imagine the warmer sofboxes to work less artificial in some situations without the need of using gels, but I'd intuitively favour to have absolutely neutral sofboxes and modify them if needed.

    - What would you do in my situation?

    Thanks a lot in advance!


     
  2. Designer

    Designer Been spending a lot of time on here!

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    You shouldn't have to gel any lights at all, never mind one or two out of a group. Are these lights all the same?

    Please provide a hotlink to the lights you bought.

    If these are continuous lights, then I will suggest that you get electronic flash instead.
     
  3. Braineack

    Braineack Been spending a lot of time on here!

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    take a picture with them both on and see if it matters.

    if i shoot using my softbox and an umbrella of a different manufacture, i can see the umbrella has a different WB.
     
  4. Guille77

    Guille77 TPF Noob!

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    The flashes are not the problem. I have three flashes of one model and four of another, so I can build at least any three-light setup with exactly the same lights. It's the fabric of the softboxes where the problem lays.




    It does matter. And I think the difference is bigger than between two "white" softboxes from two different manufactures. It looks as Jinbei had two different kind of fabrics on their catalogue, purposely. And at least by some online shops it's a matter of luck which one you get.
     
    Last edited: Aug 17, 2017
  5. Derrel

    Derrel Mr. Rain Cloud

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    As they age, many softbopx diffusing fabrics become yellower. I have a now 30-years-old softbox from Chimera: it has gorwn VERY yellow inside, and the front panel is VERY yellow. I also have some VERY yellowed white shopot-through umbrellas from the 1980's...pretty much SUPER-yellow, about 500 Degrees Kelvin too yellow.

    These are perfectly fine for Black and White work!

    I dunno...the issue with so much Made in China (MIC) stuff is the variability in quality and the variation in the raw materials.

    I suspect that the more-neutral-looking stuff has UV brighteners in it, that make the material LOOK whiter to the human EYE...but might not really make any difference to the camera sensor.

    Sometimes, a person might WANT a slightly-yellower, warmer-toned modifier's fabric. A good case in point: I have a mix of UN-coated Speedotron flashtubes, and warmer, coated flashtubes. I've used the warmer softboxes and umbrellas I have with the UN-coated flashtubes, with good success.

    I woukld TEST them out, using a fixed, set white balance on the camera. SEE for yourself if the difference is bad, or even notable. See how many degrees Kelvin the difference actually is.
     
  6. Guille77

    Guille77 TPF Noob!

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    So I did a few tests today with a gray card and two identical softboxes with the mentioned white and light coloured inner and outer diffusers, mounted on two also identical Godox AD600BM studio flashes. I shot in RAW, transfered the pictures to the computer, imported them in Lightroom, and made a white balance correction clicking over the card. These are the values of the slider after the correction for both flashes:

    No diffusers: 7300K/7300K. Almost identical, depending on where you click, as expected. But shouldn't they have been around 5500K? More on this later.
    With outer diffuser only: 7100K/8400K
    With outer and inner diffuser: 6900K/8600K

    These are my conclusions according to these results. Please correct me if I'm wrong:

    1) The baseline value, without diffusers, is absurdly high. I've doble checked it in another place of the room with a speedlite and the results are similar. As I've shot in RAW, camera adjustments should have no influence here. So I must assume my grey card (which I've just bought for this test) is crap, despite very good opinions in Amazon. Or is there any other explanation for this?

    2) The diffusers of both softboxes are, as the naked eye already suggests, extreme, and preclude any combined use of both softboxes in the same set. I also think this is not only production variability. I must actually have diffusers of two different types, with purposedly different material and color characteristics.

    3) The "white" softbox lowers the temperature of the bulb slightly, so from (accepting the theoretical color temperature of the flashes) 5500K you actually get around 5100K. The "yellow" softbox raises it up to 6800K.

    So the conclusion is, I should get rid of all of the toolboxes with one or the other kind of diffuser. The question is, which one? I think you more often need a slightly warmer light than a colder one when you want to combine it with natural light outdoors (and maybe that's the reasoning behing Jinbei offering such different diffusers). The change of +1300K of the yellow diffusers is rather extreme, but I see few reasons for wanting a -400K correction on the light source either.

    Any suggestions is welcome. Thanks a lot! :)
     
  7. Designer

    Designer Been spending a lot of time on here!

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    Gray is gray, as long as it has no color tint either way. White also works well.

    Why not perform an experiment of sorts? Line up all your softboxes in a line adjacent to each other (touching is fine) with the fronts all in a line, and at about the same height. Set all of them to the same power setting and snap a shot. Post that shot on here so we can see the difference in color for ourselves.

    We might not be able to solve the problem, but right now all we're doing is guessing what they look like.

    You've got one hour, and your time starts ... NOW!
     
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  8. Derrel

    Derrel Mr. Rain Cloud

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    You shot in raw: but how was the camera's white balance set? Did you set the WB manually, or let it run in auto?
     
  9. Guille77

    Guille77 TPF Noob!

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    ... which may well be the case with a low quality card.


    I've just done it, with two softboxes. All other softboxes have diffusers like one of those too, so that's enough. Besides, I don't have so many flashes of the same kind. I'll post the results in a while.


    WB was set at 5500K. But AFAIK WB settings on the camera have no effect on the RAW files. I've just made a test, and the only difference is the initial position of the color temperature of the slider in Lightroom. If you set it to the same value, all pictures look just the same.
     
  10. Guille77

    Guille77 TPF Noob!

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    So, as Designer suggested, here is a direct comparison of two stripboxes with identical studio flashes and different diffusers. WB is set at 5500K in camera (which shouldn't matter) and in Lightroom:

    DSC_7306.JPG

    Using a well illuminated point of each of them as reference color for the color temperature correction in LR, the left (the one I thought was "neutral") one sets it at 6900-7200K, and the right one (the one I thought was "yellow-ish") at 5800-6000K.

    I'm starting to get a bit confused with the whole thing, but contrary to what I thought before, the "neutral" diffuser is actually the one that makes the biggest change of the light color (makes light around 1500K cooler, if we assume the flash and softbox walls give 5500K), while the "yellow-ish" might not be too warm, as I thought, but actually slightly cold (around 400K). I think yesterday I took it the other way around.

    As a second test I took two photos of both strip boxes separately to check their histograms:

    DSC_7307.JPG DSC_7308.JPG

    Hystogram_Left.JPG (Left stripbox alone)
    Hystogram_Right.JPG (Right stripbpox alone)

    So that seems to confirm that both diffusers are actually a bit "blue-ish", with the left one having a much stronger blue component than the right one. Even if the right one looks to me clearly yellow. Besides, the right one seems to let less light through.

    Am I interpreting everything right? Any comments?
     
    Last edited: Aug 17, 2017
  11. Derrel

    Derrel Mr. Rain Cloud

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    White Balance does matter if it is allowed to fluctuate in AUTO, and if the As-Shot profile is used when importing the files to Lighroom... Setting the WB to a fixed point determines the color interpretation that will be applied to the images in their default status. At times, when you shoot flash in AUTO WB, but the light is flourescent or strong incandescent, the camera "sees" that continuous light, and applies that WB setting to flash-lighted images. You followed the best procedure in your test: manually pre-setting a white balance, from which the camera and software will determine the 'correcty' color of everything.

    The blueish fabric might very well have UV-enhancers added to the fabric; I assume the blue-ish one appears "white" to the human eye, as a result of the UV-enhancing stuff added to the fabric at the time of manufacturing.

    Comment: if you have color-corrected flash tubes, which look slightly yellowish, the cooler fabric might look good. If you have plain, non-UV-coated flashtubes, which look like and are plain, clear, clear,clear glass...then the slightly-yellower fabric ought to look fine.

    "Some people" like to use cooler flashtubes on their backgrounds, and then use coated, warmer flashtubes on their foreground people...it's a sort of old convention.

    One possible area to look at is always the flashtube itself! UV-coated, or plain?
     
  12. Designer

    Designer Been spending a lot of time on here!

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    They sure do look dissimilar! Can you install new diffusing fabric in them?
     

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