Update on the vanishing blue.

[JBW]

The following shot is a puzzle. If you put a color picker on it you will find no blue.



In the original post there was much discussion on why there was no blue.

I went out today and took shots of lizards, passion fruit flowers, poppy plants and the vanishing blue flower.

Only the vanishing blue flower has no blue.

Could it be that the yellow is so powerful that it over saturates the shot and obliterates the blue?

[Manfred M]

Brian - colour theory basics here. The complement of blue is yellow. Pure blue means that there is no yellow at all. If there is no blue, you get pure yellow

If an image is too blue, decreasing the amount of blue is identical to adding yellow. If the image is too yellow, then decreasing the yellow is identical to adding blue.

[JBW]

Brian - colour theory basics here. The complement of blue is yellow. Pure blue means that there is no yellow at all. If there is no blue, you get pure yellow

If an image is too blue, decreasing the amount of blue is identical to adding yellow. If the image is too yellow, then decreasing the yellow is identical to adding blue.

Then my basic theory is correct it's not a C1 malfunction nor is it shooting at -0.3 it is simply that this flower has a wickedly yellow center?

[xpatUSA]

The following shot is a puzzle. If you put a color picker on it you will find no blue.



In the original post there was much discussion on why there was no blue.

I went out today and took shots of lizards, passion fruit flowers, poppy plants and the vanishing blue flower.

Only the vanishing blue flower has no blue.

There is no blue because the 'vanishing blue' flower fills the whole frame ...

Could it be that the yellow is so powerful that it over saturates the shot and obliterates the blue?

No, Brian, that is not how it works. The sensor can capture yellows that are far outside the sRGB gamut -even outside Prophoto.

Open your raw file in ProPhoto working space. There will be some blues if Capture One is any good.

I just opened a similar color flower raw in my camera's converter set to ProPhoto working space. The histogram showed some blue and the color picker showed blues around 10/255.



I re-opened the same raw set to sRGB working space. The histogram showed crushed blues and the picker showed zero blue on the petals, just like yours.



Quite normal for orange flowers. No puzzle at all. The fix is to reduce saturation: it doesn't take much.

[JBW]

Thanks, I'll have to be more subtle.

[george013]

Brian - colour theory basics here. The complement of blue is yellow. Pure blue means that there is no yellow at all. If there is no blue, you get pure yellow

If an image is too blue, decreasing the amount of blue is identical to adding yellow. If the image is too yellow, then decreasing the yellow is identical to adding blue.

That's for printing, subtractive.
On the screen the colors are additive and blue means just blue, no red or yellow.
https://en.wikipedia.org/wiki/Additive_color
https://en.wikipedia.org/wiki/Subtractive_color

George

[george013]

Thanks, I'll have to be more subtle.

In a 8bit RGB system there're 256x256x256=16777216 colors. And among them there're 65536 colors without blue at all. So why should there be blue at all? Your colors are mainly build with R and G. If you want more blue in that image include some sky. If that color is equal as you saw it yourself, then its the right color.

George

[xpatUSA]

In a 8bit RGB system there're 256x256x256=16777216 colors. And among them there're 65536 colors without blue at all. So why should there be blue at all? *** Your colors are mainly build with R and G. If you want more blue in that image include some sky. If that color is equal as you saw it yourself, then its the right color.

George

*** George, that tells us how much you know about the spectral reflectance of flowers and how much you know about sensor spectral response. Your grossly over-simplified post is not likely to help Brian in any way.

Sorry.

[george013]

*** George, that tells us how much you know about the spectral reflectance of flowers and how much you know about sensor spectral response. Your grossly over-simplified post is not likely to help Brian in any way.

Sorry.

You may explain us, Brian and me. In additive colors yellow is red and green. No blue. And with red and green there're 65536 combinations left, from red till green and between that all kind of yellowish. Why does a yellowish flower contain blue?

Another question to you. You called that image over saturated. Is that a personal taste?

George

PS.
At the end there're 3 sliders you can play with.
https://www.w3schools.com/colors/colors_picker.asp

[xpatUSA]

You may explain us, Brian and me. In additive colors yellow is red and green. No blue. And with red and green there're 65536 combinations left, from red till green and between that all kind of yellowish.

This Children's Guide to additive color does not help our discussion about flowers in the world of nature.

Why does a yellowish flower contain blue?

1) All lighting has some emissivity at low wavelengths.
2) All flowers *** have some reflectance between 300 and say 550nm.
3) All cameras have some response in the blue parts of the CFA over that range.

*** https://www.biomotionlab.ca/Text/chittka_VR_94.pdf p.1504

Therefore, a correct raw to RGB conversion will show some blue, assuming no gamut clipping.

Another question to you. You called that image over saturated. Is that a personal taste?

No.

If an RGB image of a natural object such as vegetation or flower petals has any value at zero then the saturation is 100%, according to the HSV/HSB color model, and the image is probably not natural.

PS.
At the end there're 3 sliders you can play with.
https://www.w3schools.com/colors/colors_picker.asp

The link is an insult to my intelligence. Not appreciated.

[ccphoto]

Technical stuff makes me crazy....then I was not the best math student and as a bit of a painter, I have to stop and rethink RGB in light terms rather than color mixing terms.

That said, I have yet to find any camera, this includes Hasselblad X1D digital that do not tend a bit toward the blue spectrum. It may be the design of the sensor or a Kelvin anomaly but in any case, if you find you have a bit more than you like, you can build a custom WB like I have to eliminate any such color casting.

[Manfred M]

That's for printing, subtractive.
On the screen the colors are additive and blue means just blue, no red or yellow.
https://en.wikipedia.org/wiki/Additive_color
https://en.wikipedia.org/wiki/Subtractive_color

George

No - it works this way in RGB colour spaces too. Adobe's Photoshop colour balance tool demonstrates this quite nicely in its layout. This is set for use in an RGB colour space. If I set the colour space I'm working with to CMYK, the tool looks identical. Colour theory is the same for both these colour spaces.

[ccphoto]

No - it works this way in RGB colour spaces too. Adobe's Photoshop colour balance tool demonstrates this quite nicely in its layout. This is set for use in an RGB colour space. If I set the colour space I'm working with to CMYK, the tool looks identical. Colour theory is the same for both these colour spaces.

This is sometimes the easiest way to adjust for an imbalance.

[xpatUSA]

No - it works this way in RGB colour spaces too. Adobe's Photoshop colour balance tool demonstrates this quite nicely in its layout. This is set for use in an RGB colour space. If I set the colour space I'm working with to CMYK, the tool looks identical. Colour theory is the same for both these colour spaces.

Agreed because the sliders are moving between the complementary (opposite) colors of the additive color wheel, not those of this subtractive (painter's) wheel:

[Manfred M]

Technical stuff makes me crazy....then I was not the best math student and as a bit of a painter, I have to stop and rethink RGB in light terms rather than color mixing terms.

That said, I have yet to find any camera, this includes Hasselblad X1D digital that do not tend a bit toward the blue spectrum. It may be the design of the sensor or a Kelvin anomaly but in any case, if you find you have a bit more than you like, you can build a custom WB like I have to eliminate any such color casting.

Have you checked your computer screen? If you are finding this to be a consistent problem, regardless of the camera, I would suggest you look at the rest of your hardware. My laptop display was quite blue straight out of the box and doing a custom profile fixed that issue. Is your screen calibrated and profiled?

[Manfred M]

Brian - getting back on topic a bit.

Are the images that you posted straight out of camera and have little to no modifications in Capture One? Having a look at an image that has not been modified in any way would be useful.

[xpatUSA]

Brian - getting back on topic a bit.

Are the images that you posted straight out of camera and have little to no modifications in Capture One? Having a look at an image that has not been modified in any way would be useful.

Is the OP image still a puzzle? I thought I had solved it in post #4.

[Manfred M]

Is the OP image still a puzzle? I thought I had solved it post #4.

I'm not sure you have, which is why I am asking Brian the question. When I look at the stamen, in his shot, they have a decidedly orange colour to them and they usually tend towards the black, so I suspect that he either pushed the image or the white balance being off might be contributors to the issue.

[xpatUSA]

I'm not sure you have, which is why I am asking Brian the question. When I look at the stamen, in his shot, they have a decidedly orange colour to them and they usually tend towards the black, so I suspect that he either pushed the image or the white balance being off might be contributors to the issue.

Thanks for the clarification, Manfred.

So, you do not agree that saturation is the whole issue.

[Manfred M]

I am looking for the cause of the issue rather the outcome. Is the image saturated? Yes. Only two of the channels are contributing the the colours as the third channel has a zero value.

That is fine, but I am more interested in what happened to cause this. I suspect that will be more useful to Brian than simply suggesting that the issue is saturation.