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Author Topic: How to control a white background to keep it neutral  (Read 3246 times)

BrianWoolf

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How to control a white background to keep it neutral
« on: May 14, 2014, 05:58:03 pm »

Hello,
The only way that I can control a white or light gray background to keep it neutral is with the TEMP slider in the Basic Develop module in LightRoom. Is there another way to do this?
I photograph police and fire badges on a white background. I do fine with the gold badges but the "silver" ones cause me a lot of problems. I did a user preset for the gold badges and it works well for them. The "silver" badges, often have a slight cast of yellow, red or magenta, so they don't quite look silver. I correct this in Photoshop but its always more work than it should be. I am trying to find a solution in LightRoom and the only thing that changes the white is the TEMP slider. I am looking to see if there is a better way.
Thanks
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Petrus

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Re: How to control a white background to keep it neutral
« Reply #1 on: May 14, 2014, 06:08:27 pm »

Why not use the neutral WB eyedropper tool? Just get a sample of a neutral spot (background) with it and the colors fall in place.
« Last Edit: May 15, 2014, 11:02:09 am by Petrus »
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Schewe

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Re: How to control a white background to keep it neutral
« Reply #2 on: May 14, 2014, 06:42:59 pm »

Try using the RGB per channel curves...
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jrsforums

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Re: How to control a white background to keep it neutral
« Reply #3 on: May 14, 2014, 07:28:55 pm »

Adjustment brush and reduce saturation
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John

nemophoto

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Re: How to control a white background to keep it neutral
« Reply #4 on: May 15, 2014, 10:37:18 am »

Use something like an ExpoDisc (I have two), to take and create a custom WB before you even shoot. From there, if you still need additional tweaking, as Petrus suggested, use the WB eyedropper on the background.
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BrianWoolf

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Re: How to control a white background to keep it neutral
« Reply #5 on: May 15, 2014, 01:31:17 pm »

Thanks for the replies. I left out some information in trying to make the post less complicated. I am looking for a simple, kind of one button solution that is a no brainer. The badges come in every few months and I only want to add simple items to my processing list.

Nemophoto: I did start with a gray card on this project but it was left behind in trying to make the gold badges 'pop' properly. The WB eyedropper tool works fine on my white background to achieve a neutral image.

jrsforums: the adjustment brush seems overly complicated, as I want a universal, whole photo solution (trying to make the work simpler). I did try the reduce saturation previously but when it starts to have a good effect, it looks like a b&w image. It is necessary for the badge to look rich and have some depth of color and that means at least normal color space.

Mr. Schewe: had a hard time locating the rgb curves (in spite of having LuLa's LR3 & LR4 videos), as I had the other panel visible and just didn't realize that the button was a button. So I found them, but I am a CMYK guy and rgb curves are a bit strange to me. While curves are very powerful, they do need quite a bit of finesse. Opening the B curve seemed to do what I needed but it seemed to effect the temp slider. I would rather have a temp slider value of 4300 than a 'b' curve, as the numerical value is a lot easier to remember and re-instate than a curve if thing get messed up.

Petrus: In spite of have the WB eyedropper sitting plain as day next to the temp slider it wasn't on my radar. I have had so-so results with WB eyedroppers over the many years, some work better than others. The one in LR works quite well, when I click on the background, I get a even neutral light gray, but the badge is still yellowish. If I use the WB eyedropper on the badge it becomes a very neutral gray and this is wrong too. For my purposes, I need the CMYK values of the Badges to be in the C12, M10, Y8, K0 range, to get the silver badges to look like a great silver.

So I have found out some more useful info on LR and can get a very flat neutral with the WB eyedropper. I know where the rgb curves are, if ever I need them. For my purposes, getting a great looking silver on the badges using the TEMP slider and pushing in to the cooler numbers (past neutral) will be best for the silver badges.

Thanks, Brian
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jrsforums

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Re: How to control a white background to keep it neutral
« Reply #6 on: May 15, 2014, 02:22:46 pm »

Brian, I guess I am a little confused on what you are trying to control.  The title says background, yet you talk about the badges.

I am not sure how you alter either one on a global basis without effecting the subject.

John

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John

JeanMichel

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Re: How to control a white background to keep it neutral
« Reply #7 on: May 15, 2014, 05:07:41 pm »

Hi,
Remember that your shiny badges are mirrors; you really need to photograph them in a lighting tent in order to control coloured reflections. Including a target such as Colorchecker in the setting up shots will also help.
Jean-Michel
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dennbel

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Re: How to control a white background to keep it neutral
« Reply #8 on: May 16, 2014, 11:12:57 am »

If you find a setting(s) that works, make a preset.
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Geraldo Garcia

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Re: How to control a white background to keep it neutral
« Reply #9 on: May 18, 2014, 02:35:03 am »

Any questions regarding pictures taken with white background should be directed to Amazon from now on.  ::)
I wish that was a joke.
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Bart_van_der_Wolf

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Re: How to control a white background to keep it neutral
« Reply #10 on: May 18, 2014, 06:45:40 am »

Any questions regarding pictures taken with white background should be directed to Amazon from now on.  ::)
I wish that was a joke.

Hi Geraldo,

Indeed.

Of course, one could also purchase the perhaps best book on lighting principles, and just use their suggestions about "Bright field" (chapter 7) lighting in general, and multiple suggestions (with image examples) about the surface on which to shoot. Talking about prior art and I still fail to understand how Amazon got the patent approved.

As for the OP, I assume poster Jean-Michel hit the nail on its head, control surface reflections by controlling surrounding ambient colors. Using a really neutral reference like a Whibal to set overall White balance never hurts, because the background may not be spectrally neutral either (e.g. due to optical brighteners in reflective surfaces).

Cheers,
Bart
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== If you do what you did, you'll get what you got. ==

BrianWoolf

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Re: How to control a white background to keep it neutral
« Reply #11 on: May 18, 2014, 02:17:45 pm »

jrsforums; apologies for being confusing, often I have a hard time trying to come up with a topic heading that fits but is accurate about what I am trying to find out. At the time, I was trying to figure out how I could move white areas in LR. I do this in Photoshop with Image>Adjustments>Selective Color>White. I figured it I could neutral out the white there might be controls that let me move it where i needed it. The badges are the product and the background gets siloed out but still the 'white background' should look reasonable. Since the 'Silver' Badges contain a lot of white and 'gray' I am always using Photoshop's Selective Color>White to correct them.

Actually as I have played with it more and more Schewe's rgb curves seem to do a very nice job in working the white background and silver badges.

Of course I tent the badges and light them as flat as I can. That is why I love LR, those presets are incredible useful. It is just that the badges have to look right. Here is a finished 'silver' badge, with the background having C8,M6,Y0,K0.
Thanks again this did help me.
Brian
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