Shadows - a simple (?) question.

[xpatUSA]

Cameras with Foveon sensors are often said to lack colorfulness in "the shadows". I have been playing with ways and means to improve that, not that they are the subject of this post.

My question is:

For any image (not just from a Foveon) What is the range of image Values ** in HSV terms that comprise "The Shadows"?

Is that range a box-shape where values for example suddenly become Mid-tones, Or is a curve involved?

Opinions or references are invited.

Searching the web on the subject brings numerous mentions of "The Shadows" but I've yet to find any numbers that define them.

** or Lightness or Luminance.

[Manfred M]

Cameras with Foveon sensors are often said to lack colorfulness in "the shadows". I have been playing with ways and means to improve that, not that they are the subject of this post.

My question is:

For any image (not just from a Foveon) What is the range of image Values ** in HSV terms that comprise "The Shadows"?

Is that range a box-shape where values for example suddenly become Mid-tones, Or is a curve involved?

Opinions or references are invited.

Searching the web on the subject brings numerous mentions of "The Shadows" but I've yet to find any numbers that define them.

** or Lightness or Luminance.

Ted, I don't thing there is a range of values that defines what a shadow is.

If I head out to my favourite photo shop and ask to buy a scrim (a diffuser), they are going to offer me a 1/4 stop, 1/2 stop. 1 stop or 2 stop material. That tells me a shadow is typically viewed as something as little as 1/4 stop reduction of light.

Conversely, when I talk to other portrait photographers, they will talk about lighting ratios as high as 2:1 (i.e. a 1 stop difference between full light and the darkest shadow) which casts soft shadows are typically used to sculpt faces of females or children. If one wants "dramatic" light, 3:1 or 4:1 lighting rations are common. Split lighting can have one side of the face with areas that are close to pure white and the shadow side of the face can be almost pure black.

I've never heard of anyone refer to "the shadows" in terms of hsv values.

[xpatUSA]

Ted, I don't thing there is a range of values that defines what a shadow is.

Manfred,

Yes, I do realize that "a shadow" can have any range of values. I was talking more about the oft-quoted "the shadows" as found in statements like "to bring out the shadows" or "I'd lift the shadows", etc.

If I head out to my favourite photo shop and ask to buy a scrim (a diffuser), they are going to offer me a 1/4 stop, 1/2 stop. 1 stop or 2 stop material. That tells me a shadow is typically viewed as something as little as 1/4 stop reduction of light.

Understood. That would be a reduction of incident light as opposed to darker areas of an image.

Conversely, when I talk to other portrait photographers, they will talk about lighting ratios as high as 2:1 (i.e. a 1 stop difference between full light and the darkest shadow) which casts soft shadows are typically used to sculpt faces of females or children. If one wants "dramatic" light, 3:1 or 4:1 lighting [ratios] are common. Split lighting can have one side of the face with areas that are close to pure white and the shadow side of the face can be almost pure black.

Again, your main comment is about lighting and my question was about dark areas in a processed image.

I've never heard of anyone refer to "the shadows" in terms of hsv values.

Pardon me for using an incorrect term for image brightness. I did also mention luminance and lightness.

I take the point that "the shadows" normally refers to shaded parts of a scene and therefore that "a shadow" can have even a value or luminance or lightness of only a quarter-stop lighter than something nearby.

Therefore, I accept that "the shadows" is an incorrect descriptor. I hereby change that term to areas of low exposure (illuminance at the sensor in my world). That change divorces lighting and image brightness from "the shadows" and makes my original question somewhat moot, grump.

Following your post, I am no longer asking for opinions or references.

[pnodrog]

In Lightroom I often use the shadows and highlights sliders after setting the black and white point sliders. The shadow slider seems to act like an exposure control applied to the lower half of the tonal range via a luminosity mask. My impression is that the mask is most "transparent?" at about the mid point of what I class as shadows. (zone III of X)

I am probably wrong but thinking of it that way seems to work for me.

PS Sorry Ted I wrote this before I noticed that you were no longer asking for opinions or references. A pity as I think it's a fairly important topic.

[DanK]

It's a continuum. I wouldn't pay any attention to an arbitary cut score even if I were to find one.

[xpatUSA]

In Lightroom I often use the shadows and highlights sliders after setting the black and white point sliders. The shadow slider seems to act like an exposure control applied to the lower half of the tonal range via a luminosity mask. My impression is that the mask is most "transparent?" at about the mid point of what I class as shadows. (zone III of X)

I am probably wrong but thinking of it that way seems to work for me.

PS Sorry Ted I wrote this before I noticed that you were no longer asking for opinions or references. A pity as I think it's a fairly important topic.

No problem, Paul. An interesting reference to the Zone system which is more relevant to my opening statement than the common but vague term "the shadows":

Cameras with Foveon sensors are often said to lack colorfulness in "the shadows".

Here's a similar system which I posted here quite a while ago:



The lighting is clearly defined which leaves only the scene's reflectances to consider and Kodak's "step" 5 and 6 appear to match your opinion as to the shadows' mid-point.

The only complication that I can see is the camera settings i.e. aperture and shutter which affect the sensor exposure. I'm still looking at improving saturation and contrast in under-exposed areas of an image but, in accordance with Manfred's kibosh, without thinking of those areas as "shadows".