How do you color-correct????

[Pa]

If you are totally lost, use levels. SET EACH channel RGB to high and low points individually. This works with any camera any time any light.

I recall doing that 12 or more years ago when I was first learning raw processing with Nikon Capture. I was getting some really strange color casts, so I gave up on that approach.

But trying it today with DxO PL5, it seems to give good results.

The experiments I described in Post #31 were primarily intended to test Ronald's suggestion, as I found it worked pretty well in subjective tests yesterday. Comparing it to using the "dropper" in DxO PL5 to correct the color using the Colorchecker Passport, it worked quite well as long as the only light source was from the window as described in post #31.

However, when I tried it on the mixed window and incandescent lighting it was less successful. The results were pretty close to the uncorrected photos.

Similar results to those were obtained when I used Auto WB A1. Here is an example in mixed lighting:

Auto WB A1

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Same image, corrected using color card

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​

Auto WB clearly produced a blue tint.

 

[Pa]

I would think the same would apply to regions of the world with unusual lighting such as the poles.
Although we didn't have a "Artic" tune for our ISP's AWB algorithm. Maybe we should have.

That's an interesting point. I have many photos made during my trip to Antarctica four years ago. I will look at them now with an eye toward color correction.

 

[Pa]

That's an interesting point. I have many photos made during my trip to Antarctica four years ago. I will look at them now with an eye toward color correction.

I just did that. I was shooting with both a D7200 and a D750 back then, so couldn't use my "eye test" as I do now with my mirrorless cameras. I used Auto WB throughout the trip.

Looking at the photos now, and using the eyedropper WB tool in DxO PL5 on a spot on the snow I think should be white, I find that AWB produces a very slightly blue cast. But it was very close.

 

[Growltiger]

Here is a quick summary of the whole process.

1. Calibrate your monitor. I do this in a dark room using an X-Rite ColorMunki. This gives you a file which is used by your operating system.

2. Calibrate your printing. The profile can be supplied by the paper manufacturer or by making one yourself. I have used the X-Rite ColorMunki for this, it is time consuming. Each profile file is specific to three things:
- The make and model of printer
- The exact paper
- The exact ink
Prints should be evaluated/proofed under controlled lighting conditions, special viewing booths can be bought for the purpose, such as this one:

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3. Calibrate your camera. This has been discussed above. An X-Rite ColorChecker Passport can be used to make exact profiles for every individual photographic shoot if needed, using it again and again throughout the day as the weather or time of day changes.

4. Even after doing all that and producing the best reproduction of reality one can manage, there is a good chance that you don't want reality, you want something better. A bloodless face in the cold might look better with a warmer hue.

5. You also need to consider the problems with human vision when the result is seen. It is very complex, having a fair attempt at automatic white balance built-in. What people see is not always what is in front of them. Consider this image, where all the balls are, in reality, of identical colour. If you don't believe me use the eyedropper tool in Photoshop to check.

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[acnomad]

What Richard describes is a rigorous process, but worth it when the highest level of precision is required or desired. I have done it when truly necessary for certain clients but cannot be bothered with such an effort for my day-to-day work.

However, I do regularly accomplish the first step with a Datacolor SpyderX. This is a fairly easy and worthwhile step to ensure that I at least send to the lab what I intended.

 

[FredAzinger]

Richard -- yep, that's the onerous process for total precision.
Monitor and printer cal is always needed.
It's your step #3 that becomes impractical if not impossible in some situations.
And, I think it's not color-cal that your doing in step 3, but WB cal.

Interesting optical illusion pic - thx for sharing.

 

[Growltiger]

Richard -- yep, that's the onerous process for total precision.
Monitor and printer cal is always needed.
It's your step #3 that becomes impractical if not impossible in some situations.
And, I think it's not color-cal that your doing in step 3, but WB cal.

Interesting optical illusion pic - thx for sharing.

It is easy to do step 3, you simply need to take a photo of the ColorChecker each time you need to, you could do one because the sun comes out for example. You don't need to do anything with that photo at the time. In postprocessing you create a profile from each photo and apply it to the photos taken at that time. X-Rite have a video on the subject.

The profile created in step 3 is not just WB. The profile adjusts all the parts of the spectrum. That is why the ColorChecker has lots of different colour patches.
(see photo of it message 41 above)

 

[Butlerkid]

It is easy to do step 3, you simply need to take a photo of the ColorChecker each time you need to, you could do one because the sun comes out for example. You don't need to do anything with that photo at the time. In postprocessing you create a profile from each photo and apply it to the photos taken at that time. X-Rite have a video on the subject.

The profile created in step 3 is not just WB. The profile adjusts all the parts of the spectrum. That is why the ColorChecker has lots of different colour patches.

FWIW.....For my shooting, I find that I need to create only ONE custom color profile taken in bright sun per camera and it serves over 90% of my images. And it does surprising well for my architecture images shot in mixed lighting. At the most, at times I have to simply use the eye dropper in ACR to establish and somewhat neutral color balance, then perhaps skew it a bit to warm it up. Total time required is about 10 seconds to adjust the custom color profile when necessary, which is infrequent.

 

[Growltiger]

FWIW.....For my shooting, I find that I need to create only ONE custom color profile taken in bright sun per camera and it serves over 90% of my images. And it does surprising well for my architecture images shot in mixed lighting. At the most, at times I have to simply use the eye dropper in ACR to establish and somewhat neutral color balance, then perhaps skew it a bit to warm it up. Total time required is about 10 seconds to adjust the custom color profile when necessary, which is infrequent.

I agree. The example I was giving covers the most extreme need for perfection. For example if you were photographing a model for many hours in changing light, this would give you consistent skin tones throughout.

 

[Butlerkid]

I hesitated to post this, but there are some misconceptions about what a custom camera color profile is, how to create one and what it does. For instance, a custom camera color profile does NOT remove the beautiful color cast in sunrise or sunset images! Example of image using custom camera color profile.

First, many people do not care about these sometimes small color differences between what they photographed and the colors in their image. Others do care. To each his own....................

I am NOT trying to convince everyone they should care about using custom camera color profiles! PLEASE don’t flame me too badly. LOL!

A custom camera color profile is much more than a WB setting. It is a tool to ensure that the colors in an image generated by a camera match the colors in the scene. After all the raw image is the source document for all future use!

Most folks recognize the benefits of calibrating their monitor. And calibrating printer settings. To calibrate a monitor, the computer s/w displays a serious of colors (specific RGB values) and uses a hardware device to measure the RGB values displayed by the monitor. If the color values match, wonderful! If they don’t, the s/w creates a color profile such that the monitor will display the correct colors.

Thus, if an image of a sunset is displayed, the monitor calibration doesn’t change the rich, warm tones of the sunset. The monitor simply displays the same colors that were in the image! That is essentially what happens when a custom camera color profile is created.

In my layman’s terms below is a simplistic explanation of how the custom camera color profile is created when using the Xrite (now Calibrite) Color Checker Pro (CCP).

The CCP color card contains 24 color patches. EACH color patch is a very specific combination of red, blue and green (RGB) values. Reference

A photo is taken of the card in bright sunlight, with the card basically filling the frame.

The image is then loaded into the Xrite software. The s/w recognizes the color swatches and measures the colors in each square of the image that the camera created. Let’s use red, square 15 as an example. The color should have RGB values of 175/64/50 since that is the exact color of square #15 on the CCP card.

However, the image from the camera may reveal that square #15 has a different RGB value…. because perhaps the red color in the image is a bit more blue or orange or pinkish than the red on the card that was photographed.

The s/w analyzes each color square and the variations in color from the known colors on the card. The s/w then writes a small set of code to adjust each color so that it matches the card that was photographed. The process is similar to calibrating a monitor!

By using the resulting custom camera color profile, that colors in images taken by the camera will match the colors that were being photographed. A photograph of a red poppy with display the same color red as in the poppy. A photograph of a green field will match the colors of green in that field. A photograph of a glorious golden sunset will match the golden light in that sunset!

A custom camera color profile can be created under a various lighting situations. It may be created using the sun, which is how I create my custom camera profiles. But it can also be done using incandescent light (or any other light source).

I use a custom color profile to ensure that the photos of wildlife, birds and architecture that I photograph have accurate colors. Since I know that the colors will be accurate, I don’t even think about Kelvin settings either before, during or in post processing! I just shoot.

YMMV…...

 

[Pa]

I don’t even think about Kelvin settings either before, during or in post processing! I just shoot.

With Auto white balance?

 

[Butlerkid]

With Auto white balance?

Yes.

 

[Walter Rowe]

I hesitated to post this, but there are some misconceptions about what a custom camera color profile is, how to create one and what it does. For instance, a custom camera color profile does NOT remove the beautiful color cast in sunrise or sunset images! Example of image using custom camera color profile.

First, many people do not care about these sometimes small color differences between what they photographed and the colors in their image. Others do care. To each his own....................

I am NOT trying to convince everyone they should care about using custom camera color profiles! PLEASE don’t flame me too badly. LOL!

A custom camera color profile is much more than a WB setting. It is a tool to ensure that the colors in an image generated by a camera match the colors in the scene. After all the raw image is the source document for all future use!

Most folks recognize the benefits of calibrating their monitor. And calibrating printer settings. To calibrate a monitor, the computer s/w displays a serious of colors (specific RGB values) and uses a hardware device to measure the RGB values displayed by the monitor. If the color values match, wonderful! If they don’t, the s/w creates a color profile such that the monitor will display the correct colors.

Thus, if an image of a sunset is displayed, the monitor calibration doesn’t change the rich, warm tones of the sunset. The monitor simply displays the same colors that were in the image! That is essentially what happens when a custom camera color profile is created.

In my layman’s terms below is a simplistic explanation of how the custom camera color profile is created when using the Xrite (now Calibrite) Color Checker Pro (CCP).

The CCP color card contains 24 color patches. EACH color patch is a very specific combination of red, blue and green (RGB) values. Reference

A photo is taken of the card in bright sunlight, with the card basically filling the frame.

The image is then loaded into the Xrite software. The s/w recognizes the color swatches and measures the colors in each square of the image that the camera created. Let’s use red, square 15 as an example. The color should have RGB values of 175/64/50 since that is the exact color of square #15 on the CCP card.

However, the image from the camera may reveal that square #15 has a different RGB value…. because perhaps the red color in the image is a bit more blue or orange or pinkish than the red on the card that was photographed.

The s/w analyzes each color square and the variations in color from the known colors on the card. The s/w then writes a small set of code to adjust each color so that it matches the card that was photographed. The process is similar to calibrating a monitor!

By using the resulting custom camera color profile, that colors in images taken by the camera will match the colors that were being photographed. A photograph of a red poppy with display the same color red as in the poppy. A photograph of a green field will match the colors of green in that field. A photograph of a glorious golden sunset will match the golden light in that sunset!

A custom camera color profile can be created under a various lighting situations. It may be created using the sun, which is how I create my custom camera profiles. But it can also be done using incandescent light (or any other light source).

I use a custom color profile to ensure that the photos of wildlife, birds and architecture that I photograph have accurate colors. Since I know that the colors will be accurate, I don’t even think about Kelvin settings either before, during or in post processing! I just shoot.

YMMV…...

Very good explanation Karen. You can load these custom camera profiles into various software packages since they are ICM profiles. For Adobe software they are written as DNG files, but for Capture One it will write an ICM file. Lightroom, Capture One, Adobe Camera Raw all will use these custom camera profiles if told to do so.

X-Rite has an extensive 59-page PDF on color management.

 

[Growltiger]

Very good explanation Karen. You can load these custom camera profiles into various software packages since they are ICM profiles. For Adobe software they are written as DNG files, but for Capture One it will write an ICM file. Lightroom, Capture One, Adobe Camera Raw all will use these custom camera profiles if told to do so.

X-Rite has an extensive 59-page PDF on color management.

Yes, an excellent explanation, Karen.

I think one of the reasons for some people's confusion is they are used to setting a "Custom White Balance", and when one mentions using a card they imagine you mean a grey card used to set the white balance.
So that all gets confused with using a ColorChecker and creating a custom camera profile. As you say it is very similar to a monitor profile or a printer profile.

As Walter says, X-Rite have lots of excellent material on their website.

 

[Walter Rowe]

Yes, an excellent explanation, Karen.

I think one of the reasons for some people's confusion is they are used to setting a "Custom White Balance", and when one mentions using a card they imagine you mean a grey card used to set the white balance.
So that all gets confused with using a ColorChecker and creating a custom camera profile. As you say it is very similar to a monitor profile or a printer profile.

As Walter says, X-Rite have lots of excellent material on their website.

What we are really discussing is Input profile. Raw editor software makers create input profiles for each camera. With these Color Checker profiles we are simply replacing the software’s Input profile with our own.