Contrast adjustment in RGB mode saturation increase

[Peter_DL]

There is no necessary mathematical reason for the Tone Curve or other contrast tool to change saturation with a change in contrast when adjusting photos in an RGB colour space. The Photoshop developers programmed it this way intentionally because the tonality looks more natural and pleasing adjusted in that manner.

Mark, - The mathematical explanation why RGB tone curves also change color saturation is not particularly difficult. We can delve into the equations (if you want so), but it is simply a side effect of the per-RGB-channel-application of the curve, which alters the R:G:B intensity ratios per color depending on the shape of the curve.

Peter
--

[Tim Lookingbill]

Mark, - The mathematical explanation why RGB tone curves also change color saturation is not particularly difficult. We can delve into the equations (if you want so), but it is simply a side effect of the per-RGB-channel-application of the curve, which alters the R:G:B intensity ratios per color depending on the shape of the curve.

Peter
--

And add to that the nonlinear behavior of backlit RGB displays per channel intensity ratios as the curve within the software sends varying levels of voltages to make each RGB combo bright or dark through the video card and onto the display's RGB subpixels. With this level of complexity it's a wonder we see anything close to looking like what we captured with our cameras.

[digitaldog]

With this level of complexity it's a wonder we see anything close to looking like what we captured with our cameras.

It's why we don't. What our cameras produce don't look anything like what we're seeing or what we get!

[MarkM]

There is no necessary mathematical reason for the Tone Curve or other contrast tool to change saturation with a change in contrast when adjusting photos in an RGB colour space. The Photoshop developers programmed it this way intentionally because the tonality looks more natural and pleasing adjusted in that manner. Try increasing contrast without increasing saturation, as you can do with the Luminosity blending mode, and you will see immediately the rationale. But there are ways to moderate that behaviour using layers and blending modes to suit your taste.

This isn't what I see when I look at how the curves work. It seems like a very simple implementation that does exactly what it says: applies a curve equally across each channel. An increase in saturation is a natural consequence of this. The greater the ratio between the dominant (highest) channel and the lowest channel, the higher the saturation (in Photoshop's implementation). When you apply an S-curve this ratio increases where the curve is steeper, which in turn increases the saturation. That doesn't mean it wasn't a conscious choice by the Adobe engineers, but it is also a natural consequence of the simplest implementation you could use.

[MarkM]

It's all in the higher mathematics of digital imaging and programming - not my field.

There's not a lot of higher mathematics going on here. Take the the smallest RGB value and divide by the biggest. Subtract that value from 1 and you have what Photoshop reports as saturation. For example RGB(189, 37, 60) - Saturation is 1-(37/189) = 0.804. Photoshop reports 80% Knowing this you can see how a curve that increases contrast will also increase saturation.

[Mark D Segal]

Mark, - The mathematical explanation why RGB tone curves also change color saturation is not particularly difficult. We can delve into the equations (if you want so), but it is simply a side effect of the per-RGB-channel-application of the curve, which alters the R:G:B intensity ratios per color depending on the shape of the curve.

Peter
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There could be both intent and side effects at play, depending on the specific aspect at hand. Please see post #4 above.

[Mark D Segal]

That doesn't mean it wasn't a conscious choice by the Adobe engineers, but it is also a natural consequence of the simplest implementation you could use.

OK, we agree that the behaviour *could have been* a conscious choice of the Adobe engineers. Not being a digital imaging programmer or an Adobe employee I certainly have no feel for how simple or complex their implementation is, but thanks for the insight into the simplest one. At that level, I agree, we're dealing with some pretty basic arithmetic, but there could be more to it. Anyhow, I think the important point of the discussion to retain is that we are not locked-in to any particular implementation. We have the tools in both LR and PS to dial-in just about whatever combination of saturation and contrast that suits us. For practical purposes that would satisfy most results-oriented folks who are less concerned about how Adobe did their thing under the hood, and more focused on what we can do with the applications over the hood.

[Mark D Segal]

With this level of complexity it's a wonder we see anything close to looking like what we captured with our cameras.

In addition to Andrew's comment that's why the quality of the demoasaicing process, camera profiles and colour management of our displays and printers is so important. And yes, I agree, how stringing all this stuff together allows us to produce such high quality photographic renditions is indeed wonderful, and a tribute to the groups of engineers and programmers who made it possible.

[digitaldog]

In addition to Andrew's comment that's why the quality of the demoasaicing process, camera profiles and colour management of our displays and printers is so important.

Tim also needs to study up on the concept of cameras and their significant observer metamerism compared to humans and their behavior with respect (or lack thereof) of the the Luther-Ives condition.

[Guillermo Luijk]

Very simple example:
R=150
G=100
B=100

is a reddish tone because it has more Red than Green and Blue. If we apply a typical contrast curve in RGB blend mode:



R gets higher than 150 and both G and B lower than 100, let's say:

R=160
G=90
B=90

What is that? another reddish colour where R is more apart from G and B than in the begining, i.e. a more saturated reddish colour.

I have to say that most times RGB blend mode curves work better than Luminance blend mode in PS. RGB saturates but Luminance unnaturally desaturates.

Lab is not perfect either. It can't be, it's just a good model but in the real world you can always add more red light while Lab can't help to desaturate when increasing its L* for being limited in a closed range of values:




Just to finish, this kind of straight curve is the only one that can implement a change in exposure over any linear or pure gamma image:



Curiously it has to be applied in RGB blend mode or saturation and hue changes will take place. In RGB it mimics a change of exposure in the camera (no hue/saturation change, R/G/B ratios are preserved).

Regards
 

www.guillermoluijk.com

[Bart_van_der_Wolf]

This isn't what I see when I look at how the curves work. It seems like a very simple implementation that does exactly what it says: applies a curve equally across each channel. An increase in saturation is a natural consequence of this. The greater the ratio between the dominant (highest) channel and the lowest channel, the higher the saturation (in Photoshop's implementation). When you apply an S-curve this ratio increases where the curve is steeper, which in turn increases the saturation. That doesn't mean it wasn't a conscious choice by the Adobe engineers, but it is also a natural consequence of the simplest implementation you could use.

Mark is correct, neither mumbo jumbo nor genius are required, it is just a direct consequence of a simplistic implementation of a contrast change in RGB colorspace.

And in the process of fanboyism (it's so much easier to criticize others than admit shortcomings in one's own processing tools) from some of the contributors for the dated way of image editing, people may also have missed one of the improved features of Capture One version 9, an improvement of the Contrast, Brightness, and a little improvement of the Saturation controls, and of the way they interact. Also the R/G/B and  L curve controls are a huge improvement. Luma can be separately used for contrast adjustment curves, and simultaneously now more subtle R/G/B curves adjustments can be applied.

I must say that these controls now allow for a much faster workflow in adjusting the overall look, while maintaining robust color quality. We no longer get very over- or under-saturated colors when contrast is adjusted. Prior to this version upgrade, it used to require multiple corrections (which is why many hardly used those controls) to get the saturation back to where it looked best, now only a simple contrast or brightness adjustment is often enough.

Also skin colors retain their healthy look despite even strong adjustments in contrast, which allows to shoot in softer, more balanced light, and add contrast in post (knowing that the camera could capture more of the original color without underexposure noise or overexposed highlights, and contrast changes no longer screw up colors).

Cheers,
Bart

[Mark D Segal]

Mark is correct, neither mumbo jumbo nor genius are required, it is just a direct consequence of a simplistic implementation of a contrast change in RGB colorspace.

Well, well: I'd be interested to know how you know this. Are you a programmer of Photoshop? Have you seen the math they used, studied their algorithms? I haven't, but I'm just asking on what authority you are making this statement. Implicit in your statement is the notion that they don't know any better, hence the use of the word "simplistic" rather than just "simple", as opposed to more complex. Suppose they did opt for a simple implementation of the relationship - if that's the effect they wanted to produce, what's wrong with it? You only add complexity as needed/wanted.

[/quote]
And in the process of fanboyism (it's so much easier to criticize others than admit shortcomings in one's own processing tools)
[/quote]

Why are you trying to impute irrational motives to a technical discussion? Different people are entitled to a different opinion, based on their knowledge and working experience about how the tools in this or that application perform without being "fanboys", are they not?
 

[/quote]
............the dated way of image editing, people may also have missed one of the improved features of Capture One version 9, ..........
[/quote]

What is this dated way of image editing? Some things that are dated are just fine, others deserve improvement. The time since an algorithm was developed can be truly irrelevant if it still works well and does the job people want and expect of it, especially as in this case all kinds of things are refined under the hood with every upgrade. If it doesn't continue to work well and something better comes along, only then does it become dated. Now as for Capture 9 - sure - a very high quality application, I agree with you; A professional who knows it inside-out demoed it to me in detail late last year and I think it has some very attractive and tempting features. But for the time being I am remaining with LR for other reasons, an important two of which are (1) it's well-integrated workflow capabilities, and (2) with every upgrade it delivers more and more new features that provide the results I find photographically satisfying. I just don't see the incremental benefits relative to the incremental costs of renovating my whole digital imaging environment, as such as change would require.

For me, Bart, the bottom line is that a raw file is a raw file and will need adjustment no matter what it's starting point. I have never opened a raw file in the past twelve years that I have been shooting raw that didn't need adjustment regardless of the camera or the editing application. For me, LR and as needed Photoshop provide what I need to make high quality photographs with the luminance, hues and saturation values I want for the photo at hand. There are areas for improvement in LR I'm aware of that haven't been addressed in this thread, but they are OT relative to the question the OP raised. I know there are other applications out there with which one can do likewise, perhaps some more easily than others, but that is a different question. And by the way, this is not a new topic; the contrast/saturation linkage issue has a pedigree going well back in time; people agreed to disagree back then and this will probably continue to be the case indefinitely. With this, I think I have put in about the amount of time I can give to this thread. La Lutta Continua (probably without me)!:-)

Cheers.

[Schewe]

OK, we agree that the behaviour *could have been* a conscious choice of the Adobe engineers.

Well, I'll confirm that it was a conscious choice of one engineer, Thomas Knoll. He didn't do curves this way because it was "simpler" or "easier" or "faster" but because the curves algorithm as it is in Photoshop and Camera Raw looked better to him (they are, or course different algorithms but written to achieve similar results). In fact, Thomas tried several (if not many) different algorithms before finally settling on the way curves work now in PS/ACR.

One can argue that different methods produce different results and sometimes some results are better than other results depending on the images and what is needed to adjustment. But to argue one method is antique and "modern" methods are better (presumably because they are newer) is pretty naive and is letting a bit of an anti "something" to show through...PS/ACR/LR do things a certain way...if you like the results, keep learning how to use them better.

If you don't like the results Bart, feel free to use something else. But calling somebody a fanboy is really kinda juvenile in any reasonable debate or discussion. It pretty much works against you and your argument–particularly when the video you claimed showed a better way was such a piece of crap. You have yet to prove your point regardless of the hand waving you've been doing :~)

[Bart_van_der_Wolf]

Well, well: I'd be interested to know how you know this. Are you a programmer of Photoshop? Have you seen the math they used, studied their algorithms? I haven't, but I'm just asking on what authority you are making this statement.

Hi Mark,

Thanks for the honest questions. Obviously I'm not an Adobe programmer but, besides the in my eyes glaringly wrong output, it is not that difficult to reverse engineer what is happening under the hood. So yes, I've studied the behavior of what their algorithms do, and they basically just apply a standard (sort of S-curve) contrast transform in the RGB space. It doesn't look like they do much else, because I can replicate the effect (not that I'd want to in actual image processing) by using a mathematically similar curves adjustment to all three R/G/B channels.

Implicit in your statement is the notion that they don't know any better, hence the use of the word "simplistic" rather than just "simple", as opposed to more complex. Suppose they did opt for a simple implementation of the relationship - if that's the effect they wanted to produce, what's wrong with it? You only add complexity as needed/wanted.

Sure, it is a slightly exaggerated qualification, meant to snap people out of their non-critical state of worship. Shock therapy as it were. The choice to implement it as they did is apparently deliberate, and it was immediately questioned/challenged, or so it seems from the earlier quoted text, by a very clever guy Eric Chan whom I think highly of.

Why are you trying to impute irrational motives to a technical discussion? Different people are entitled to a different opinion, based on their knowledge and working experience about how the tools in this or that application perform without being "fanboys", are they not?

Shock therapy ...
 

What is this dated way of image editing? Some things that are dated are just fine, others deserve improvement.

Non-intelligent e.g. contrast adjustments are a dated way. And there is a reason why Photoshop allows Luminosity blended adjustment layers ..., they do know that the current implementation sucks, unless one uses very small amounts (where the errors will be less visible).

The time since an algorithm was developed can be truly irrelevant if it still works well and does the job people want and expect of it, especially as in this case all kinds of things are refined under the hood with every upgrade. If it doesn't continue to work well and something better comes along, only then does it become dated.

Not really, it was a compromise from the get go, and speed of execution was deemed more important than higher perceptual accuracy.

Now as for Capture 9 - sure - a very high quality application, I agree with you; A professional who knows it inside-out demoed it to me in detail late last year and I think it has some very attractive and tempting features. But for the time being I am remaining with LR for other reasons, an important two of which are (1) it's well-integrated workflow capabilities, and (2) with every upgrade it delivers more and more new features that provide the results I find photographically satisfying. I just don't see the incremental benefits relative to the incremental costs of renovating my whole digital imaging environment, as such as change would require.

I understand that, but that's all the more reason to send a very clear message that these antiquated tools need to be improved, like their competion has been doing for years, and finally C1 also made the next step. Late, but better than never. I have not yet looked at Affinity Photo (because it's not yet available for Windows), but it would not surprise me if they also use a more intelligent approach.

For me, Bart, the bottom line is that a raw file is a raw file and will need adjustment no matter what it's starting point. I have never opened a raw file in the past twelve years that I have been shooting raw that didn't need adjustment regardless of the camera or the editing application. For me, LR and as needed Photoshop provide what I need to make high quality photographs with the luminance, hues and saturation values I want for the photo at hand. There are areas for improvement in LR I'm aware of that haven't been addressed in this thread, but they are OT relative to the question the OP raised.

I know there are other applications out there with which one can do likewise, perhaps some more easily than others, but that is a different question.

I agree, although getting the Raw conversion 'right' without the need to iterate between controls in order to remove errors that are introduced by other tools, and vice versa, is a real time saver. For a certain project, I've lately been shooting and editing something like 5000 to 6000 images, and postprocessing them for publication. I can tell you, every minute saved without compromising output quality, is a huge benefit.

And by the way, this is not a new topic; the contrast/saturation linkage issue has a pedigree going well back in time; people agreed to disagree back then and this will probably continue to be the case indefinitely. With this, I think I have put in about the amount of time I can give to this thread. La Lutta Continua (probably without me)!:-)

Then why doesn't Adobe address the issue, one might ask. Competitors have.

To help understand the issue, in a non-mathematical way, I've attached 2 TIFF files in a ZIP archive. They are in ProPhoto RGB colorspace. The file named "Colorshift_100vs040.tif" has three gradients, one channel of each is running linearly in 32 steps from dark to light. The other channels desaturate the main channel by adding 40% of their color. You can check by dividing the relevant channel value by the channel value that desaturates the main channel. Rounding to integers aside, you should get 40% response.

Now add, for clarity sake (not that you'd be likely to use that much in practice) 100 Contrast, and read the response ratio's again (I've added a version in the ZIP file). They will vary above extreme shadows which are off the chart but limited also by low value precision from say 21% to 26 % instead of 40%, meaning that there is less desaturation, which boosts the saturation to unacceptably extreme deviations from their baseline (which now has an S-curve). Differences of 1% or more are already visible in a direct comparison.

Cheers,
Bart

[Mark D Segal]

Bart, thanks, but my whole conceptual problem with this discussion is the notion of somehow "getting the raw conversion right" in some mostly automated manner. I agree with you that minimizing processing steps needed to produce a photo that is "right" in the mind's eye (because it is always so), would be desirable, especially in a mass production context. The problem for an application developer is that this is for the most part subjective and varies from photo to photo; the artistic side of this is that we actually do "make" the photo we imagined from the scene we captured. So they make judgments in designing these algorithms about what they think will satisfy most of the people by coming closest to finish earliest most of the time. But they know they will never satisfy all the people all the time.

To think back about how old this dilemma is, I remember back in the 1950s discussions I had with friends from Central Europe about the differences between Kodachrome and Agfachrome or Kodacolor and Agfacolor. The Kodak products produced kind of contrasty, saturated results while the Agfa products produced flatter, less saturated results. Which was better? Essentially it depended whether you came from North America or Central Europe, apart from dissidents like me who actually liked Agfacolor - perhaps I spent too much time in Central Europe. :-)  Anyhow, you get the point.

Now fast forward to 2016 "a few decades" later and here I am using LR to convert my raw files. I would say, that even with PV 2012 which produces more contrast out of the box than the previous PVs did, more often than not I find myself INCREASING contrast AND INCREASING Vibrance, because I import them with everything "zeroed and linear" so-called (which under the hood it really isn't). I do this on purpose so that I can dial in my own decisions without needing to first undo other peoples' decisions. So I suppose, the introspection of my own practice and findings going back years now on a great many photos tells me that this is not an issue I should be concerned about. And if I feel a contrast move is adding a bit too much saturation, it takes a couple of seconds to damp it down a bit. Even if I multiply that by X operations in an evening, I'm not losing sleep over it.

[Bart_van_der_Wolf]

One can argue that different methods produce different results and sometimes some results are better than other results depending on the images and what is needed to adjustment. But to argue one method is antique and "modern" methods are better (presumably because they are newer) is pretty naive and is letting a bit of an anti "something" to show through...PS/ACR/LR do things a certain way...if you like the results, keep learning how to use them better.

Hi Jeff,

I find that (learning how to use better, when it's wrong to begin with) a very unproductive approach, which avoids any chance of improvement of something that (according to many) does not work well at all. You seem to argue that when something (sort of) worked in the past, that newer insights will not produce better results, without even doing an honest verification of that hypothesis. I could reverse the argument and claim that it is that attitude that is pretty naive.

If you don't like the results Bart, feel free to use something else.

I do, but should I therefore stop trying to educate people about the way that their favorite applications could be improved? If they are unaware, will they ask for better tools? Or are you suggesting that users of an application should not ask for more than they get handed out, and act more like sheeple.

But calling somebody a fanboy is really kinda juvenile in any reasonable debate or discussion.

You are missing the point.

The Germans have a nice saying that pretty much sums it up for me: "Was sich liebt, das neckt sich". An English version could be something like: "the quarrel of lovers is the renewal of love".

It is because I care about Photoshop as my main image processing tool, that I am critical about it's deficiencies. That is something that fanboys cannot understand, hence I'll let those whom the shoe fits wear it.

You have yet to prove your point regardless of the hand waving you've been doing :~)

I'll give it another try, although a true fanboy will not be convinced by any reasonable argument (regardless of the presentation), it's behavior that's also called "cognitive dissonance". I'm an optimist, so I believe there is hope for those who are willing, therefore another attempt.

Attached there is a ZIP archive with 3 images.

a) One image as downloaded from BabelColor.com is the source of this experiment, it's called "ColorChecker_sRGB_from_Avg_16bit.tif". I took that image because it is easily displayed even on displays with modest capabilities, and it has several common/relevant colors for investigation, like skin tones, and some tones we can find in nature/landscapes. There are other colors not in the chart that are more critical, like those of flowers. So the effects demonstrated in the ColorChecker, can become even more visible in other subject matter.

b) An image called "ColorChecker_sRGB_from_Avg_16bit_ACRContrast+000_ProPhotoRGB.tif" is a simple import of that file in ACR, and exported as a ProPhoto RGB version of the file, the default working space of many users. No changes were made, no sharpening, no noise reduction, nothing. This will serve as the baseline to compare against. So any hidden changes to the file data would be present in the file, just to make sure we will compare apples to apples.

c) An image called "ColorChecker_sRGB_from_Avg_16bit_ACRContrast+100_ProPhotoRGB.tif" after only applying a +100 Contrast adjustment, nothing else was changed.

The images 'b' and 'c' were saved without any further alterations as they came out of Photoshop's ACR plugin, so they are as you could create them from the original image 'a' yourself, but I've spared you the exercise and thus it is also possible for non-Photoshop users to follow the proceedings or for those who do not want to fiddle with their settings and are afraid to change their current setup.

Now, let's have a look at e.g. the first (Row 1, Column 1) , "Dark skin" patch.
After the ACR conversion to ProPhotoRGB, image 'b' now reads in 8-bit colors:
RGB=[81, 68, 55], Lab=[38, 13, 14], HSB=[30°, 33%, 32%]
After the ACR Contrast boost and conversion to ProPhotoRGB, image 'c' now reads in 8-bit colors:
RGB=[79, 60, 40], Lab=[36, 19, 23], HSB=[31°, 50%, 31%]

Because it is a darkish color, the contrast adjustment made it darker still, as intended. But it also increased the saturation, just look at the coordinates in Lab, _a and especially the _b values increased significantly, or the HSB coordinates which even show a slight Hue change, a significant Saturation increase by 17% (whereas a 1% difference is usually visible in a direct comparison).

I know that the +100 Contrast adjustment in ACR is extreme, but that's just to make it easier to see what also happens at lower settings, albeit obviously with lower amounts.

Let's have a look at e.g. the second (Row 1, Column 2) , "Light skin" patch.
After the ACR conversion to ProPhotoRGB, image 'b' now reads in 8-bit colors:
RGB=[157, 136, 113], Lab=[66, 16, 18], HSB=[30°, 28%, 62%]
After the ACR Contrast boost and conversion to ProPhotoRGB, image 'c' now reads in 8-bit colors:
RGB=[191, 162, 133], Lab=[75, 20, 22], HSB=[31°, 31%, 75%]

Again, we not only see an intended change in brightness, but also an additional increase in Saturation, and it's expected when we change brightness channels with the same amount in the R/G/B channels in RGB space instead of doing it in the correct manner. Because Luma and Chroma are not decoupled in RGB colorspace, a change to one will affect the other in the wrong way.

One more color patch, relevant to landscape photographers, the third (Row 1, Column 3) , "Blue Sky" patch.
After the ACR conversion to ProPhotoRGB, image 'b' now reads in 8-bit colors:
RGB=[95, 102, 134], Lab=[50, -4, -22], HSB=[230°, 29%, 53%]
After the ACR Contrast boost and conversion to ProPhotoRGB, image 'c' now reads in 8-bit colors:
RGB=[104, 114, 163], Lab=[55, -6, -31], HSB=[229°, 36%, 64%]

The results speak for themselves, Saturation is again exaggerated compared to the intended change in Brightness.

The amount of the Saturation change will vary a lot, especially with medium and lower Brightnesses and with already rather Saturated colors (one or two channels with a low contribution) like those in the second row of the Colorchecker. I'll leave the analysis of those for the readers, but if such colors are part of the scene, they will suffer even more than the more neutral colors.

I could continue, but I assume that the pattern is clear by now.

Now, the naysayers might argue that that exaggeration of Saturation with increased contrast is more pleasing, well I disagree. There is a reason why many others raise questions about the saturation changes, like the OP, or programmers who devise perceptually better methods that produce more natural/pleasing results.

Well arguing about taste is pretty useless, but maybe we can quickly look at how nature intended things to be.

Again, take the first patch, "Dark skin": RGB=[81, 68, 55], Lab=[38, 13, 14], HSB=[30°, 33%, 32%]
When we plug the RGB values into Bruce Lindbloom's excellent CIE Color calculator (see attachment), and change the RGB model to ProPhoto RGB, then the Lab values come out at the exact same values (after rounding to integer numbers). So we've verified that Photoshop uses the same (correct) color coordinate calculations.

When we now change the luminance 'Y' value in xyY coordinates from 0.102501 to say 0.090082, we'll get about the same drop in the L channel as ACR produced ( Lab=[38, 13, 14] -> Lab=[36, 19, 23] ), L=38 becomes L=36. However, instead of boosting Saturation like ACR does, according to Bruce's calculator the Saturation should have been reduced a bit (in line with the reduced luminance), the color should have become RGB=[75, 63, 51], Lab=[36, 12, 13] to look as nature intended it.

So we may conclude that ACR produces Saturation values that are not how natural Contrast changes would affect color/saturation. Some find that acceptable, others like me don't. Even if it were true, after research results would be published for peer review, that people prefer those unnatural color changes (just like some like overprocessed HDR images), it would be much better if that was left to the users to begin with.

Because first oversaturating, and then desaturating in a different way, will not be as accurate, nor will it be easy (due to how color vision works). We as humans are not that good at absolute color (due to preconditioning and changes due to ambient luminance levels), but better at color differences (almost simultaneous observation). When we are preconditioned with an oversaturated version, it becomes harder to restore to natural color. In Photoediting, it is usually best to start with a neutral basis (only adjusting exposure and contrast), and then alter colorbalance / local color / Saturation to better match a creative intent.

Cheers,
Bart

[Schewe]

Well arguing about taste is pretty useless, but maybe we can quickly look at how nature intended things to be.

Congratulations Bart, you've now taken your argument down the road that "NATURE" intended contrast adjustments without saturation adjustments. Care to point that out in the "Rules Of Nature" booklet?

Yes, your convoluted and complicated argument and proofs prove that ACR increases contrast and saturation–pretty sure we agree on that, right? The only point of contention is that Thomas sees it correct to increase saturation when increasing contrast while you consider that an act against nature...do I have that right?

Thomas said he decided to increase saturation when increasing contrast because that's what happens to film when you push process, you increase contrast AND saturation. Thomas was a film photographer well before he wrote Photoshop so when he designed his tools for digital imaging he decided to make the digital emulate the analog film appearance.

One can ague that was a mistake and an abomination of nature but somehow it just does not rise to that level with me.

Use whatever tool floats your boat but unless legions of users line up in protest against ACR's saturation increase when increasing contrast (by +100) I'll bet Thomas will STILL keep the saturation and contrast tied together because he honestly thinks it's the right thing to do. If that makes ma a fan boy...I'll wear those shoes–they are comfortable and make me look marvelous!

BTW, I did download your files and played...actually C1 8.x contrast increase sure looks about the same as ACR. I haven't built out a file and read the samples yet. I'll try to get to it, but I do kinda have a life outside of LuLa ya know...Have a nice Sunday. I'm gonna go see Finding Dora so I don't have to worry about Camera Raw screwing up my images for a couple of hours. That will be a relief!!!

[Bart_van_der_Wolf]

Congratulations Bart, you've now taken your argument down the road that "NATURE" intended contrast adjustments without saturation adjustments. Care to point that out in the "Rules Of Nature" booklet?

Yes, your convoluted and complicated argument and proofs prove that ACR increases contrast and saturation–pretty sure we agree on that, right? The only point of contention is that Thomas sees it correct to increase saturation when increasing contrast while you consider that an act against nature...do I have that right?

Hi Jeff,

Unnatural looking edits, not an act against nature. I'm beginning to see why you talked about a juvenile response earlier, it may have something to do with the mindset of the beholder.

Thomas said he decided to increase saturation when increasing contrast because that's what happens to film when you push process, you increase contrast AND saturation. Thomas was a film photographer well before he wrote Photoshop so when he designed his tools for digital imaging he decided to make the digital emulate the analog film appearance.

One can ague that was a mistake and an abomination of nature but somehow it just does not rise to that level with me.

While that may have influenced his mindset and the resulting decision to go with that choice at the time, there is no need to persist with that if new insights show that it's demonstrably producing issues with digital image processing. Had he made the decision today, he probably would have chosen a different approach. Nothing wrong with that. We all learn as we go, and hindsight has 20/20 vision.

However, principles become dogmas when people stop (re)thinking, that can become dangerous. Other software makers are rethinking and adopting the more natural way of contrast adjustment.

BTW, I did download your files and played...actually C1 8.x contrast increase sure looks about the same as ACR.

Yes, they fixed that in C1 version 9. Now it produces much more natural results, works great and it's a real time saver.
BTW Also C1 changes saturation when contrast is adjusted, but it looks much more natural. It is hard to do a direct comparison, because of the difference in the color engines, but I'll try to find something based on a Raw file that demonstrates the differences.

I haven't built out a file and read the samples yet. I'll try to get to it, but I do kinda have a life outside of LuLa ya know...Have a nice Sunday. I'm gonna go see Finding Dora so I don't have to worry about Camera Raw screwing up my images for a couple of hours. That will be a relief!!!

Have a nice Sunday. I've heard that "Finding Dory" is considered to be a great movie, already scoring an 8.1 out of 10 on IMDB. Have fun.

Cheers,
Bart

[Mark D Segal]

While that may have influenced his mindset and the resulting decision to go with that choice at the time, there is no need to persist with that if new insights show that it's demonstrably producing issues with digital image processing. Had he made the decision today, he probably would have chosen a different approach. Nothing wrong with that. We all learn as we go, and hindsight has 20/20 vision.

................

Cheers,
Bart

Bart, I think there may be a risk here that you are super-imposing matters of preference on matters of intellectual capability, and that could be a mistake, if I may say so. Firstly, I should remind - this is a very old debate. I was an active participant in it nine years ago in several fora and I can assure you that a number of us have examined this issue comprehensively. Back then we found no fundamental flaws with ACR's processing capabilities in the areas of greatest concern, and that was even before all the improvements that have been made since.

Secondly, it would be a grievous error to assume that the Adobe programming team doesn't have the smarts and the objectivity to take stock of what they are doing, take stock of what competitors are doing, take stock of what suits the market and react accordingly; and even if the programmers themselves didn't do this actively, you can bet your bottom Euro that their QC and Management overseers would be doing so; but these are highly professional folks with total awareness. In LR, for example, they have been through three process versions already. In each one of them they have tweaked the performance of the various tools, most notably in PV2012. At any point along that juncture if they saw the need or the desirability to change the rendering along the lines you suggest, I have no doubt whatsoever they would have done it, and they would have explained to the clientele why they did what they did, and provided an option for those who don't like it. So based on what I know of them, you cannot dismiss this team as dogmatic people who have stopped thinking. And as such, you cannot dismiss the possibility that just maybe you and others who share your perspective don't have a monopoly on the "right" answers in this area, because maybe in the final analysis there are no "right" answers - it is all a matter of the logic and preferences of one set of programmers and users versus another, both having their own legitimacy.

Well, yes, a beautiful Sunday afternoon here in Toronto as well, so good to cut the arguing and enjoy the sunshine!

Cheers.

[Schewe]

While that may have influenced his mindset and the resulting decision to go with that choice at the time, there is no need to persist with that if new insights show that it's demonstrably producing issues with digital image processing.

...in your opinion. So far, your arguments fall back to numbers and not appearance. The video you alluded to failed to make the appearance argument. So far, you've failed to provide much in the way of evidence of real world editing failing in ACR while being demonstrably better in some other app. And different is not better, it's just different. Go any images where ACR fails and some other app shines?