Shooting JPEG in color for Black and White Images

No. The primaries in this example are CMY. That's what I started with. You can't make Cyan or Magenta with RBY because CMY are the physically accurate primaries while RBY are approximations. You can however make Blue and Red with CMY, regardless if you use CMY ink or CMY paint.

If Red and Blue really were universal primaries, then why can I make them with CMY?
 
First, printers don't print by mixing colors but by layering them, and that is the main reason for the different color wheels.

You can make cyan and magenta, cyan is one part yellow two parts blue. Primaries aren't colors that can't be made from other colors, but colors that you can make all colors from.

Here is a piece from one of my studies.
"My second observation is that artists aren't working with a pure medium. The paint they are using is not just color; it is color being carried along as part of some physical product. Not only the acrylic, oil, or other base, but even the colorant as well is some mineral, extract, or other product that appears to be a particular color, but will always be "contaminated" by other colors to some degree."
 
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First, printers don't print by mixing colors but by layering them, and that is the main reason for the different color wheels.

This is just wrong. The ONLY reason why painters use RBY "Kindergarten Kolors" is tradition, it's a more limited pallet that is biased warm. Cyan Magenta and Yellow are subtractive primaries. No if's and's or but's about it. If you absorb all the light in the red wavelength from a theoretically perfect white light, the remainder is cyan, not blue ... not one part yellow light, two part blue light - rather, one part of everything else light - and that is cyan. period.
 
First, printers don't print by mixing colors but by layering them, and that is the main reason for the different color wheels.

This is just wrong. The ONLY reason why painters use RBY "Kindergarten Kolors" is tradition, it's a more limited pallet that is biased warm. Cyan Magenta and Yellow are subtractive primaries.

I thought it's because paint comes in tubes, and you mix it together to make colours and you overlay it in glazes/layers. It's additive rather than CMY subtractive.
 
No. Additive color refers to light - with each addition of more light, luminance increases. Subtractive refers to pigments and dyes, because with the addition of more pigment luminance decreases.

Another way to look at it is that pigment absorbs (subtracts) light (color) while light adds to itself. This is why you can't truly "make" Cyan and Magenta from the secondaries Red and Blue because doing so would require that you reflect more light than the components that you started with.
 
The JPEG algorithm completely destroys the blue channel of an image.

A RAW file won't compress the blue channel to buggery so you'll get a nice sharp image. A JPEG file on the other hand will suck for conversion using a blue channel.

Interesting..I didn't know this. I think I'd read that the green/blue sensitivity of a typical Bayer array was 5:1..is this correct?
 
^^ that is interesting. I wonder if compressed RAW is the reason my blue channels have been disasters.
 
And in some cases, Uncompressed RAW....

There have been a number of times with my a350 I felt I couldn't do the greyscale conversion I wanted because the blue channel was such a mess. I know that digital photography struggles with blues anyway, and always have, but if Sony's cRAW or JPEG compresses the already in poor shape blue channel it's not a good thing.
 
Do you think if we were to intentionally shoot raw using the wrong colour temperature in daylight (i.e much too cool), it would ultimately give a better blue signal for a monochrome image?

If I use an in-camera blue filter shooting jpegs..the pictures look like B&W from the 1800s...especially skin tones. But maybe adding blue with WB at the first stage of raw conversion is something to try instead.
 
No. Unfortunately color settings are performed post-exposure. The fact that color temperature is not set on the analog side of the camera is a big beef I have with DSLRs actually.

If I knew exactly the spectral sensitivity of the sensor, it should be theoretically possible to use a color meter and CC filters. Right now I know that most cameras are very green-green-blue biased, and I suspect that a magenta or FL-D filter could provide better SNR, though i haven't gotten to experiment with this yet.

I do have a strong suspicion that CC filters may still have a roll in digital photography.

Likewise, for b/w photography there is no benefit to setting the w/b at exposure. You may as well set it in RAW processing. b/w optical filters OTOH may have some benefit, i've heard this, but I am a bit skeptical.

I've also experimented with 16-bit exposure fusion from the individual RGB channels to provide greater bit depth than the camera recorded in each individual channel, with inconclusive results.
 
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No. Unfortunately color settings are performed post-exposure. The fact that color temperature is not set on the analog side of the camera is a big beef I have with DSLRs actually.

If I knew exactly the spectral sensitivity of the sensor, it should be theoretically possible to use a color meter and CC filters. Right now I know that most cameras are very green-green-blue biased, and I suspect that a magenta or FL-D filter could provide better SNR, though i haven't gotten to experiment with this yet.

I do have a strong suspicion that CC filters may still have a roll in digital photography.

Likewise, for b/w photography there is no benefit to setting the w/b at exposure. You may as well set it in RAW processing. b/w optical filters OTOH may have some benefit, i've heard this, but I am a bit skeptical.

I've also experimented with 16-bit exposure fusion from the individual RGB channels to provide greater bit depth than the camera recorded in each individual channel, with inconclusive results.


How about a blue gel over the flash?
 
yes. that would work but obviously not in every situation.
 

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