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Registered: ‎09-13-2015

How to get rid of blue?

Using a T5, take a picture in Automatic mode of an object with white paper background in the shade on a bright day. Result: paper is blue. Try Basic mode, close-up (the flower icon). Set "Light/scene-based shots" menu to Daylight and then Shade. Result: paper only slightly less blue. Anyway to get the blue all the way out?
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Registered: ‎06-11-2013

Re: How to get rid of blue?

That's a simple "white balance" adjustment.  What software do you use to edit your phoots?

 

Most editing programs have a white balance adjustment, include an eye-dropper tool that you use to click any pixel that you know to be a true neutral "white" or "gray" tone.  

 

Every color is generated by blending a certain amount of the primary colors of light (red, green, and blue).  White is simply a maximum amount of all three (e.g. if the scale goes from 0 to 255 (which is 8-bit color) then pure white is 255, 255, 255 (for red, green, and blue).    Any "gray" color is simply equal amounts of all three (e.g. 150, 150, 150 RGB would be a "gray" tone.) If you get a blue cast, it simply means you have more blue (e.g. 150, 150, 170 for RGB) would be a slightly bluer tone.

 

But if you were to select that slightly blue color (and let's suppose it is 150, 150, 170) then the software realizes that your image is about 13% more "blue" then it should be.  It will leterally subtract 13% of the blue channel from every single pixel in the image ... bringing it all back to a neutral color balance.

 

If your camera was set to a full "sun" white balance then it may have expected the images to be a bit too warm and subtracted red (leaving you with a blue cast).  If you set it to a cloudy-day white balance it will expect too much blue and subtract the blue instead.  

 

You can get more accurate white balance by shooting a single frame using something called a "neutral gray" card and using the "Custom White Balance" function on your camera to set that images as the white balance source.  You can also use that frame to get perfect white balance in the post processing (which is how it's normally done for any photographer who shoots in RAW format.)

 

Tim Campbell
5D III, 5D IV, 60Da
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Registered: ‎12-02-2012

Re: How to get rid of blue?

[ Edited ]

Well-explained by Tim.  

 

1.) Shoot in RAW, not JPG.  RAW keeps all the data the camera captures while JPG throws some data away and commits you to some of those choices.  White balance adjustment to a JPG  is particularly limited, which is one of the biggest reasons I only shoot RAW.  SURE, "get it right in camera" but when you fail to do that it sure is great to have a raw image where you can easily fix it

 

2.). If you have a white background in the shot, you should use that white to peg your white balance either in camera or in post processing.

   a.). In post processing.   It is a perfect opportunity, actually, as you normally have to hunt around in an image for a piece of real white to use for white balance.  In Lightroom there is a simple eye dropper tool you use to grab a sample from your image. 

   b.). In camera.  Shoot the white background.  Then go into MENU and use that white in the image to set a custom white balance.  I would rather do it in post but this works too.  

 

Mixed light.

if you have a mix of two light sources there can be a problem. Flash + ambient light, or window light + incandescent bulb, or window light plus shade, or whatever combination..  If there is a mix, you may need to use gels on your flash to match ambient light, or else you may need to eliminate the ambient light by under exposing the ambient into nothing so your flash as the only light.  

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
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Posts: 2,369
Registered: ‎11-14-2012

Re: How to get rid of blue?

If the scene is predominately white it may be an exposure problem. When shooting in snow you need to overexpose 1 to 2 stops to get the snow to look white.

"A skill is developed through constant practice with a passion to improve, not bought."
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Re: How to get rid of blue?


@cicopo wrote:

If the scene is predominately white it may be an exposure problem. When shooting in snow you need to overexpose 1 to 2 stops to get the snow to look white.


Very true on heavily overcast days, not so much on bright, sunny days. And when it does happen on sunny days, the problem is usually blue sky reflecting off the snow. Correction by exposure manipulation has to be done carefully; a blown highlight is a blown highlight, whether it started out white or blue.

Bob
Philadelphia, Pennsylvania USA
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Re: How to get rid of blue?

[ Edited ]

"If the scene is predominately white it may be an exposure problem ..."

 

It is more likely an exposure problem and less likely a white balance issue.  If the main most important thing is the white paper, you do need to increase the exposure.  And the best way to do that is to bracket.  Bracketing is a photographers best friend.

Underexposure can make colors look off and cool at times.

 

"RAW keeps all the data the camera captures while JPG throws some data away and commits you to some of those choices."

 

Not sure what he is trying to say but WB is always adjustable.  You can edit it in post.  It doesn't matter if it is a jpg or RAW file.

 

 When you shoot RAW a tag along file is made that is nearly the same thing as a jpg.  It just doesn't actually alter the RAW file.  It simply tells the camera or computer what settings to use.  You can not view a RAW file otherwise.

 

In a jpg the settings are applied to the actual file.  In other words it is altered.  The unused info is thrown away, forever.  This makes the amount of adjustment in post more limited.  The worst thing using jpg is the camera's routine decides what is used and what is not.  With RAW you decide!

EOS 1DX and 1D Mk IV and several lenses!
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Re: How to get rid of blue?

White balance can be adjusted on a JPG, but not nearly so well as with a JPG.  If you attempt too radical a WB change on a JPG you get a decidedly weird-looking image.  

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
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Re: How to get rid of blue?


@ScottyP wrote:

White balance can be adjusted on a JPG, but not nearly so well as with a JPG.  If you attempt too radical a WB change on a JPG you get a decidedly weird-looking image.  


I think you meant for that 2nd "JPG" to say "RAW" instead.

 

Yes, JPEG is a good "final output" format once an image no longer needs further adjustments, but isn't good as an interrim processing format because of it's "lossy" nature.  

 

Even though the sensor records the color of each "pixel" independently, it's difficult to get good compression when every value is unique.  JPEG plays upon weaknesses of the human eye -- specifically in our inability to tell when colors are different when they are really just extremely similar (but still unique).  This normalizes large areas of pixels to be identical so now the compression algorithms work extremely well.

 

Trouble happens as soon as you try to adjust an image to recover detail and you find out that the detail has been normalized out of the image. 

 

For this reason, I typically only shoot RAW. 

 

For white balance, I snap a photo that has the "gray card" displayed anywhere within the image and then put the gray card away and continue to shoot.  (note that if you change the lighting situation -- go shoot somewhere else, etc.) then you need another shot with a gray card in it.  (The white balance correction made possible by a gray card in your image is valid for all images which were shot in the same lighting situation as the image with the gray card.  As soon as you change the lighting, you need another image with a gray card for your shots in that new lighting scenario.)

 

When I'm back at my computer, I'll use Lightroom to correct the white balance and then synchronize the white balance adjustment across to all images shot in the same light (extremely easy to do with Lightroom.)

 

I only use the gray card if the type of shooting I'm doing will require accurate white balance.  That means most of the time, I don't bother.

 

There are situations where you definitely do not want to correct for white balance.  For example... if you're shooting a sunset scene, the lighting is decidedly orange and you want it to remain orange.  The sunset will no longer have that warm feel if you correct all the orange out of it by doing a white balance correction.  If I'm shooting something in candlelight... the candles create a golden light cast that I do not want to correct out of the image -- otherwise the candle light will look very cold.

 

If I'm shooting on a cloudy day, I usually want to lie about the lighting.  Cloudy days look cold.  But I can shoot subjects on a cloudy day (and frankly I'll get better lighting because the entire sky becomes one big giant soft-box) but I will deliberately "warm" the white balance to make it look like it was shot on a warmer sunnier day (except without the harsh highlights and shadows that go along with shooting in full sun.)

 

Tim Campbell
5D III, 5D IV, 60Da
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Re: How to get rid of blue?

[ Edited ]

The problem is saying a RAW is always better than a jpg.  And of course, we know, that is not true.  A RAW can be better than a jpg but is not always necessarily better.  A properly exposed, correct WB, etc., in camera jpg can look every bit as good as the same RAW in file.  In fact the jpg could wind up sharper!  Plus in the end you are going to most likely be showing and saving a jpg.

 

Photography is a complication of many things.  You can't say always shoot RAW.  You need to use what works. Like Tim Campbell, I 'almost' always shoot RAW but it is because the post is so simple and seamless these days the reasons for jpg are not as appealing as once was.

 

Geting the images you want is the important thing.

EOS 1DX and 1D Mk IV and several lenses!
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Registered: ‎12-02-2012

Re: How to get rid of blue?

The problem is that real world is not perfect like the theoretical one.  If you set WB with a card, and if you nail exposure perfectly with a light meter, and if you shoot 1000 shots and nail both perfectly 1000 times in a row, then JPG is as good.  

 

Biggs you may be more precise than I am, and you may even be nearly perfect.  Not me.  I accidentally shot 2/3 of a vacation on JPG recently and KICKED myself for it, because I could not push the exposure as far and I definitely could not change the WB even remotely as dramatically as I so often do in RAW.

Scott

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?
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