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Image thickness / density - help me figure out what it is


kye

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One of the elusive things that film and images from high-end cameras have is often called "thickness".  I suspect that people who talk about "density" are also talking about the same thing.  It's the opposite of the images that come from low quality cameras, which are often described as "thin" "brittle" and "digital".

Please help me figure out what it is, so perhaps we can 'cheat' a bit of it in post.

My question is - what aspect of the image shows thickness/thinness the most?

  • skintones?
  • highlights?
  • strong colours?
  • subtle shades?
  • sharpness?
  • movement?  or can you tell image thickness from a still frame?
  • ...?

My plan is to get blind feedback on test images including both attempts to make things thicker and also doing things to make the image thinner, so we can confirm what aspect of the image really makes the difference.

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I think the light and amount of contrast of the scene makes a huge difference to the image thickness.  When you have a good amount of contrast in your scene with areas of shadow and bright highlights,

In my opinion tonality trumps dynamic range. You can have very high dynamic range but if the tonality and colour is lacking you get the 'thin' digital low-bit-depth look. A lot of smartphones hav

1980s Kodak test image from linked article 🙂

Posted Images

4 hours ago, kye said:

My question is - what aspect of the image shows thickness/thinness the most?

As others have suggested, the term "density" has a specific meaning in regards to film emulsions.

 

I think that the property of "thickness" that you seek is mostly derived from color depth (not bit depth).

 

Color depth in digital imaging is a product of resolution and bit depth (COLOR DEPTH = RESOLUTION x BIT DEPTH).  The fact that resolution affects color depth in digital images becomes apparent when one considers chroma subsampling.  Chroma subsampling (4:2:2, 4:2:0, etc.) reduces the color resolution and makes the images look "thinner" and "brittle," as you described.

 

Film emulsions don't have chroma subsampling -- essentially film renders red, green and blue at equal resolutions.  Almost all color emulsions have separate layers sensitive to blue, green and red.  There is almost never a separate luminosity layer, unlike Bayer sensors or RGBW sensors which essentially have luminosity pixels.

 

So, if you want to approximate the "thickness" of film, a good start would be to shoot 4:4:4 or raw, or shoot with a camera that uses an RGB striped sensor (some CCD cameras) or that utilizes a Foveon sensor.  You could also use an RGB, three-sensor camera.

 

 

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A "brittle" image to me (never actually used that term) in digital would be one that has too low a colour depth for the what it maybe should (could?) have and maybe has too few pixels for the image size.    Possibly has artifacts clearly visible ( maybe from bad or too much upsizing).

A good black and white image does not look brittle if it looks like it is supposed to.

I cringe now when i look at some colour photos in old glossy magazines from the 70s and 80s taken with film.

On colour depth, this is what DXO uses for stills anyway.

https://www.dxomark.com/dxomark-camera-sensor-testing-protocol-and-scores/#portrait

"Portrait score: Color Depth

Flash studio photography involves controlled lighting, and even when shooting hand-held, studio photographers rarely move from the lowest ISO setting of their cameras. What matters most when shooting products or portraits is a rich color rendition and color depth. The best image quality metric that correlates with color depth is color sensitivity, which indicates to what degree of subtlety color nuances can be distinguished from one another (and often means a hit or a miss on a pantone palette). Maximum color sensitivity reports in bits the number of colors that the sensor is able to distinguish.

The higher the color sensitivity, the more color nuances can be distinguished. As with dynamic range, color sensitivity is greatest when ISO speed is minimal, and tends to decrease rapidly with rising ISO settings. In DxOMark testing we measure only the maximum color sensitivity. A color sensitivity of 22bits is excellent, and differences below 1 bit are barely noticeable."

So for stills at least with (mostly) greater bit depth than video the very top few cameras (top 20) do seem to be MF or FF cameras with large pixel counts (Nikon Z6 being the lower MP champion for this excepted) but below that it is all over the place on MP count, sensor size and age.

My lowly aging 12mp A7s still fairs very well for portrait colour depth.    And it does better when you DO have to use higher ISOs  IE Nikon Z6 is in the top few cameras and has (according to DXO) noticeably better colour depth than may A7s until about ISO 3200 but is behind very slightly by 25600 though not noticeably and the GH5 starts at the same level as the A7s but the difference  should be very noticeable even by ISO 400.

This is in part what makes me think the new A7s iii might have wonderful colour depth since it is supposedly a 16 bit stills camera VS 14 or 12 bits for others.   

Then again, are not jpegs just 8 bit anyway?    Same with video from most cameras? The monitors/screens people are viewing images on?

Bottom line, I think it comes down to sensor size, age, design (some older Canon sensors did not do as well as others of the same age) resolution and technology...just like everything else and of course, in large part, what i think is a "brittle" image could well be very different to what someone else does.

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A good image starts with good lighting. I did an outdoor interview with a 1/2 frost shower curtain for diffusion as a key light, and reflectors for fill/back light and it completely changed my mind about lighting.

Image and skin tones looked amazing, colors looked great. I then realized why so many people's images look like poop.  If you're talking about narrative as well, you need to pay attention to your set and color design. Not to mention you know, exposing properly and working within the limits of your camera.

Without good light there's not too much you can do to save the image.  Camera's can't capture what isn't there, if you're missing spectrums in your lighting your image just won't turn out well. It's why a lot of corporate / on location stuff looks good but not great - you can't change all practicals and light sources so you deal with the factory lighting or the office lighting and make sure you have a decent key and call it a day.  And even then for most of us, our "good" lights don't even come close to the quality of sun/incandescent, but LEDs are so much easier to use and cost effective so they get used.

If you can't get the lighting and the set/frame right, then you can't do that much about it. The reason more footage from the "better" cameras looks good is that they are too expensive for most people to use, so they end up getting used by people that know how to make any camera look good and have the budget to do it right (obviously not all the time, but much higher % than randos on this forum). Give those cameras to these same randos and I imagine you'll end up with the same crappy images, just with better DR and a bit of special color processing sauce.

Try using a color chart on your next shoot too, it can actually make a difference. And maintain proper exposure, if you are trying to shoot your subject -2EV against a sunny back drop, of course it's going to look like poop.

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1 hour ago, noone said:

Maximum color sensitivity reports in bits the number of colors that the sensor is able to distinguish.

I've also checked out DXO's portrait colour rating. The last thing you'd want for a nice portrait is accurate colours. Perhaps it's better to call it a colour accuracy rating then (and who knows whether their methodology is sound or not). But accurate colour is not nice colour.

Reality looks kind of shitty, in terms of colour, compared to how its colours can be represented in photographic images.

Colour accuracy should not be the goal, IMO, unless you're reproducing artwork or products. I would like my images to look better than reality, when it comes to colour. 

So I would absolutely not expect the top rated DXO cameras for portraits to make nicer portraits SOOC than those lower on the list. 

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14 minutes ago, hyalinejim said:

I've also checked out DXO's portrait colour rating. The last thing you'd want for a nice portrait is accurate colours. Perhaps it's better to call it a colour accuracy rating then (and who knows whether their methodology is sound or not). But accurate colour is not nice colour.

Reality looks kind of shitty, in terms of colour, compared to how its colours can be represented in photographic images.

Colour accuracy should not be the goal, IMO, unless you're reproducing artwork or products. I would like my images to look better than reality, when it comes to colour. 

So I would absolutely not expect the top rated DXO cameras for portraits to make nicer portraits SOOC than those lower on the list. 

Agree (sort of), there is a lot more to it than that.     Still, there is nothing wrong with trying for accurate colour in itself and sometimes even for a portrait it IS desirable, it is an individuals choice.

Then again, I probably take fewer photos (or video) at base ISO than anyone so for ME, a camera that does well at base ISO but better at higher ISOs is more desirable than one that might be better at base but falls off a cliff as you go up (for colour depth and DR and anything else really) and that is why I still have not found anything better for me than my lowly old A7s.    Even the top camera for colour depth falls behind the A7s  fairly quickly and all the top cameras do eventually (maybe every camera so far does) though many of the best it is very close and probably not noticeable and they would be much better cameras for most people.

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18 hours ago, seanzzxx said:

Your terminology seems confused

It's not my terminology - it's what I've put together over reading many threads about higher-end cameras vs cheaper ones and how people try to quantify the certain X-Factor that money can buy you.  I've heard it enough over the years to get a sense that it's not being used randomly, nor only by one or two isolated people.  

I've seen first-hand that there are people who have much more acute senses than the majority of people.  Things like synaesthesia and tetrachromacy exist along with many others that we've probably never heard of, so just by pure probability there are people who can see better than I can, thus, my desire to try and work out what it might be in a specific sense.

16 hours ago, tupp said:

Color depth in digital imaging is a product of resolution and bit depth (COLOR DEPTH = RESOLUTION x BIT DEPTH).  The fact that resolution affects color depth in digital images becomes apparent when one considers chroma subsampling.  Chroma subsampling (4:2:2, 4:2:0, etc.) reduces the color resolution and makes the images look "thinner" and "brittle," as you described.

Interesting.  Downsampling should give a large advantage in this sense then.

6 hours ago, noone said:

A "brittle" image to me (never actually used that term) in digital would be one that has too low a colour depth for the what it maybe should (could?) have and maybe has too few pixels for the image size.    Possibly has artifacts clearly visible ( maybe from bad or too much upsizing).

A good black and white image does not look brittle if it looks like it is supposed to.

I cringe now when i look at some colour photos in old glossy magazines from the 70s and 80s taken with film.

On colour depth, this is what DXO uses for stills anyway.

https://www.dxomark.com/dxomark-camera-sensor-testing-protocol-and-scores/#portrait

 

I am also wondering if it might be to do with bad compression artefacts etc.  This was on my list to test.

Converting images to B&W definitely ups the perceived thickness - that was on my radar but I'm still not sure what to do about it.

Interesting concept from DXO - I learned a few things from that.  Firstly that my GH5 is way better than I thought, being only 0.1 down from the 5D3 and also that it's way above my Canon 700D which I thought was a pretty capable stills camera.  People always said the GH5 was weak for still images and I kind of just believed them, but I'll adjust my thinking!

6 hours ago, noone said:

Then again, are not jpegs just 8 bit anyway?    Same with video from most cameras? The monitors/screens people are viewing images on?

Yes, and then streaming video compression takes the final swing with the cripple hammer.

This has long been a question in my mind about how we can evaluate the differences between a $50k camera and a $100k camera using a streaming service that uses compression that a $500 Canon camera would look down its nose at.

I suspect that it's a case of pushing and pulling the information in post.  For example, if you shoot a 10-bit image in LOG that puts the DR between 300 and 800IRE and then you expand out that DR to 0-100IRE then you've stretched your bits to be twice as far apart, so it's now the equivalent of a 9-bit image.  Then we select skin tones and give them a bit more contrast (more stretching) and then more saturation (more stretching) etc etc.  It's not hard to take an image that was ok to begin with and break it because the bits are now too far apart.

We all know that, but the thing that I don't think gets as much thought is that the image is degrading with every operation, long before it 'breaks'.  Even an Alexa shooting RAW has limits, and those limits aren't that far away.  Have a look at a latitude test of an Alexa and read the commentary and you'll note that the IQ starts to go visually downhill when you're overexposing even a couple of stops.....and this is from one of the best cameras in the world!

My take-away from that is that I need to shoot as close to the final output as possible, so I switched from shooting HLG to Cine-D.  This means that I'm not starting with a 10-bit image that I have to modify (ie, stretch) as the first step in the workflow.  

5 hours ago, scotchtape said:

A good image starts with good lighting. I did an outdoor interview with a 1/2 frost shower curtain for diffusion as a key light, and reflectors for fill/back light and it completely changed my mind about lighting.

Agreed.  Garbage IN = Garbage Out.

Like I said above, if you're having to do significant exposure changes then you're throwing bits away as the first step in your workflow.

5 hours ago, hyalinejim said:

I've also checked out DXO's portrait colour rating. The last thing you'd want for a nice portrait is accurate colours. Perhaps it's better to call it a colour accuracy rating then (and who knows whether their methodology is sound or not). But accurate colour is not nice colour.

I think there's a couple of things in here.  You're right that accurate colours isn't the goal, Sony proved that.

But my understanding of the Portrait Score wasn't about accuracy, it was about Colour Nuance... "The higher the color sensitivity, the more color nuances can be distinguished."  What you do with that colour nuance (or lack of it) determines how appealing it will look.  Of course, any time you modify an image, you're stretching your bits apart, so in that sense it's better to do that in-camera where it's processed uncompressed and (hopefully) in full bit-depth.

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30 minutes ago, kye said:

 

Interesting concept from DXO - I learned a few things from that.  Firstly that my GH5 is way better than I thought, being only 0.1 down from the 5D3 and also that it's way above my Canon 700D which I thought was a pretty capable stills camera.  People always said the GH5 was weak for still images and I kind of just believed them, but I'll adjust my thinking!

 

 

 

NOTHING wrong with the Gh5.     IF you go to higher ISOs, it does not hold up as well as modern cameras with larger sensors but it is still ok in lower light and if you control the light is just fine.

Canon 5D3 is a very nice camera but its sensor was a bit behind some other FF sensors of its time

I think the 700D IS a pretty capable stills camera.

I keep thinking I want a Canon DSLR to use my Canon EF mount AF lenses (Sigma 150 2.8 macro for a start) and the 5D iii, even 5Dii and 6D as well as APSC cameras like the 700d and others are on my radar. 

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After doing videos for three years, I've learned an expensive camera does not always equal to an expensive and beautiful image. Part of that "Arri" look or cinematic look as people call it, is created before the camera starts to capture. 

The videos now I can shoot with very cheap camera are so much better than what I used to shoot using a Sony A7S2. Give the best camera in the world to a newbie and he is going to still have bad result. Something I only learned after quite a few bad investments. 😅

What I want to say is, a thick image with great contrast and saturation has to be created on the set, and then enhanced with camera and post production. If you can fully control the set, you don't even need log profile or crazy high bitrate or raw most of the time, though they are certainly nice to have. 

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9 hours ago, noone said:

I cringe now when i look at some colour photos in old glossy magazines from the 70s and 80s taken with film.

Yeah.  All of those photos by Richard Avedon, Irving Penn and Victor Skrebneskiphotos were terrible!

 

 

18 hours ago, tupp said:

Color depth in digital imaging is a product of resolution and bit depth (COLOR DEPTH = RESOLUTION x BIT DEPTH).

9 hours ago, noone said:

The best image quality metric that correlates with color depth is color sensitivity, which indicates to what degree of subtlety color nuances can be distinguished from one another (and often means a hit or a miss on a pantone palette).  Maximum color sensitivity reports in bits the number of colors that the sensor is able to distinguish.

"Color sensitivity" applied to digital imaging just sounds like a misnomer for bit depth.  Bit depth is not color depth

 

I have heard "color sensitivity" used in regards to human vision and perception, but I have never heard that term used in imaging.  After a quick scan of DXO's explanation, it seems that they have factored-in noise -- apparently, they are using the term "color sensitivity" as a term for the number of bit depth increments that live above the noise.

 

 

9 hours ago, noone said:

My lowly aging 12mp A7s still fairs very well for portrait colour depth.

That's a great camera, but it would have even more color depth if it had more resolution (while keeping bit depth and all else the same).

 

 

9 hours ago, scotchtape said:

A good image starts with good lighting.

That is largely true, but I am not sure if "good" lighting is applicable here.  Home movies shot on film with no controlled lighting have the "thickness" that OP seeks, while home movies  shot on video usually don't have that thickness.

 

 

19 hours ago, tupp said:

Color depth in digital imaging is a product of resolution and bit depth (COLOR DEPTH = RESOLUTION x BIT DEPTH).

2 hours ago, kye said:

Interesting.  Downsampling should give a large advantage in this sense then.

No.  There is no gain of color depth with down-sampling.  The color depth of an image can never be increased unless something artificial is introduced.

 

On the other hand resolution can be traded for bit depth.  So, properly down-sampling (sum/average binning adjacent pixels) can increase bit depth with no loss of color depth (and with no increase in color depth).

 

 

2 hours ago, kye said:

I am also wondering if it might be to do with bad compression artefacts etc.

Such artifacts should be avoid, regardless.  "Thick" film didn't have them.

 

 

2 hours ago, kye said:

Converting images to B&W definitely ups the perceived thickness

There is no chroma sub-sampling in a B&W image.

 

I really think color depth is the primary imaging property involved in what you seek as "thickness."  So, start with no chroma subsampling and with the highest bit depth and resolution.  Of course, noise, artifacts and improper exposure/contrast can take away from the apparent "thickness," so those must also be kept to a minimum.

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32 minutes ago, tupp said:

Yeah.  All of those photos by Richard Avedon, Irving Penn and Victor Skrebneskiphotos were terrible!

 

I said SOME and I purchased a couple of vintage photographic magazines (as in magazines selling photo gear) recently and the colours were terrible 

As for the rest, since I disagree with you on many things and do not want to get into another five pages of yes, no, yes, no, I will leave it at that with you.

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Multiplying resolution x bit depth will give you file size but NOT colour depth.

I am no expert on this but I would suggest to anyone doing research from those who ARE qualified as with anything photographic would be much more useful other than as general interest.

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For those interested, Google seems to work.

Mind you I can not find anyone with a definition on how to work out colour depth, but plenty on working out file sizes.

Makes sense really given that not all photos are the same size but can have varying colour depth for varying size sensors.

https://www.google.com/search?q=color+depth+calculation&oq=co&aqs=chrome.0.69i59l3j69i57j0l4.2659j0j15&sourceid=chrome&ie=UTF-8

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52 minutes ago, noone said:

For those interested, Google seems to work.

Mind you I can not find anyone with a definition on how to work out colour depth, but plenty on working out file sizes.

Makes sense really given that not all photos are the same size but can have varying colour depth for varying size sensors.

https://www.google.com/search?q=color+depth+calculation&oq=co&aqs=chrome.0.69i59l3j69i57j0l4.2659j0j15&sourceid=chrome&ie=UTF-8

 

Most of the results of your Google search echo the common misconception that bit depth is color depth, but resolutions' effect on color depth is easily demonstrated (I have already given one example above).

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A thin negative can have a lot of contrast but the image tends to go mushy and the colors have a bias towards something that is not their own color. A thick negative is not an overexposed one, overexposed negatives lose contrast and colors go more pastel. A thick negative is a negative that uses the maximal potential of the emulsion, this involves correct exposure, a contrasty scene with good lighting, textures, colors ,etc... 

In film you can add in development to help pushing things into something closer to thick, in digital you can color correct. But one thing is clear, Nothing comes from nothing.

In other words, you need a scene with a lot of information, a tool that is able to deliver a lot of information, and the technique to get out the most information from the scene through the tool onto the final presentation.

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Additional edit:

The information itself has to be cognizable, the information needs some order, this is why thick images usually have a lot of element separation (closeups, thin dof, elaborate lighting,blocking, composition).

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4 hours ago, Nikkor said:

Nothing comes from nothing.

As a teenager my dad's darkroom offered a practical wisdom built from hours of self-inflicted failure.  Buying the film and chemicals to develop one's shots, and then having them not "turn out" makes you really pay attention to the technique of achieving a strong image while in the field.  The same sentiment the OP has mentioned.

In the digital age, the notion that technology -such as bit depth and/or raw- is going to solve problems is not misguided, it's just overstated.  I used to think I could save a thin negative at the enlarger.  Nope.  I could only make it marginally better.  If it was a mess already, nothing was going to change that.  That's why shooting 8-bit or using an old digital camera, while not ideal, is also not a deal breaker.

All that said, it comes back to lighting.  Those that artistically manipulate or take advantage of light in their images are simply better at this than those that don't.  There's really no better advice than the be good with light when capturing the shot.

The curse of the internet is that folks like us can go down rabbit holes of information and then end up applying esoteric solutions to problems of extreme technical nuance, when the fundamental basic issues are the ones that require the actual attention.  It's why intuitive shooters and directors like Kendry Ty (8 years ago!) were making something remarkable on consumer gear --while bigger film productions with marginally competent, yet unimaginative, people were making complete crud.

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