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Question

What exactly is Clarity?

Forum|Forum|8 years ago
March 30, 2017
9 replies
23668 views

Hi,

camera raw and lightroom have the slider clarity.

But what exactly is clarity?
Yes I know what it is in principle, its mide ton contrast, but I'm asking for the algorithm to reproduce it in PS.
In the internet you read a lot about its like unsharp mask with large radius and small intensity. But this is true only for small corrections.
When moving the clarity-slider to the extrem right the image looks different. At first it seems that it influences only the luminosity.

But using an upper layer, applying unsharp mask (radius around 100, amount 20% -30%) and combining it with luminance-method looks quite differently.

I tried differenz things. Some come near, but not exaclty. And all what I found in the internet is rubbish and ad hoc thinking.

I need the hard slightly desaturated look when pushing clarity to the extreme.

This topic has been closed for replies.

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Paper_Mine

Participant

Some local tone-mapping algorithm for increasing local contrast.

Sharpen (convolution or deconvolution) can be seen as a low-quality local tone-mapping algorithm. (I call it low-quality because of ringing effect.)

jbm007

Community Expert

It has a sharpening function hence the ringing effect if pushed to hard.

It also crushes the blue end to much, pushing into the purple end of the spectrum.

thats one of the reasons I use it in LAB mode

D Fosse

Community Expert

But paper mine has a point - you get exactly the same effect with Unsharp Mask at high radius.

Personally I hate Clarity and never use it. It always looks over-processed, fake-HDR to me.

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ThomasTAuthor

Known Participant

Hi,
thank you to all replyer.
So I think my question has been answered.
The aswer is: clarity is some magic stuff with a history and there exist some approximaitons by using usm with large radius and small amount. At least for lower values of clarity. But the clarity-algorithm itself is keeped a secret.

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ThomasTAuthor

Known Participant

Hi,

actually I mean with *exactly* the concrete algorithm. In a way that I can programm it as a photoshop plugin or standalone image processor etc.
All what you told is not new for me ;-)

Its seems nobody except the adobe programmers really have a clue ....

Regards Thomas

Stephen Marsh

Community Expert

actually I mean with *exactly* the concrete algorithm.

Over 10 years ago a company named Pixmantec created a nice piece of software known as RawShooter that was offered in “Essentials” and “Professional” versions. This product offered two “unique” tools – Clarity and Vibrance. A few years later, Adobe purchased Pixmantec and introduced Clarity and Vibrance into Adobe Camera Raw and Lightroom (however the values/numbers in Adobe’s implementation were not exactly the same or interchangeable with the now defunct RawShooter product).

In a way that I can programm it as a photoshop plugin or standalone image processor etc.

ThomasT, this is not known outside of the programmers – for good reason! This is known as Intellectual Property, I.P. or otherwise as a trade secret. You have stated that you would like to “recreate” this effect that Adobe purchased when acquiring the assets of Pixmantec.

As has been stated, the exact code is not known. What is known is the results of using the tool, which can be used to *try* to reverse engineer the results. Many have come “visually very close” using a recipe similar to this:

Copy image to new layer
Apply a density based mask, often known as a luminosity mask (however the density could be Lightness, channel mixed etc)
Curve the luminosity mask into a “U” shape (or an inverted “U” shape depending on your curve display settings), known as a “midtone mask” or “endpoint mask” so that only the midtones are revealed (or using layer blend if sliders to do similar)
Optionally soften/blur the mask a little bit
Apply USM to the masked image using a small amount and large radius

P.S. It should also be noted that the results of using the Camera Raw filter on rendered data is quite different when compared to raw camera data.

Trevor.Dennis

Community Expert

I process the original DNGs from the blacmagic pocket cam.

Clarity works identical in both cases. Via eye. I did not check pixelvalue differences.

ThomasT wrote
I process the original DNGs from the blacmagic pocket cam.
Clarity works identical in both cases. Via eye. I did not check pixelvalue differences.

I'm guessing that you know you can overlay one version over the other, and set the upper layer to Difference? Full black indicates identical values. So the screen shot below shows the background layer copied, and a subtle curves layer clipped to the copied layer. Where the curves layer is masked it shows full black as expected. You could use this as a tool to compare and reference.

Note: the left (edited) side of the image looks darker in my browser (Firefox) than it did in Photoshop.

There are forums our there specialising in the math of image manipulation, and other companies like Topaz and On-One that produce local contrast plug-ins. Topaz is clever about it as their product range are not so very different from each other, but each one represents another revenue steam. So, like Stephen has said, it is a big ask to expect them to share their intellectual property.

Derek Cross

Community Expert

Clarity is for sharpening / softening an image.

barbara_a7746676

Community Expert

Clarity increases contrast, mostly in the midtones.

Trevor.Dennis

Community Expert

https://forums.adobe.com/people/Barbara+Ash wrote
Clarity increases contrast, mostly in the midtones.

You beat me to it Barbara, except I was going to say 'local contrast'. It stretches out the histogram dropping the black point and brightening whites, but tries not to blow highlights. But if you watch the histogram while dragging the clarity and contrast sliders to the right, the effect is very similar.

A trick some people miss is negative Clarity, which is a super easy, and very effective tool for cleaning skin blemishes. It _tries_ not to soften the blacks too much when doing this, but it is best to do it on a copied layer and mask out the eyes, lashes, hair, lips etc.

B

bzareenk

Inspiring

Haaha! Sure then, dont go over the top while editing.Keep it minimal and i think you will get the desired loo.Keep the clarity sliders on a lower value to maintain natural appearance.

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ThomasTAuthor

Known Participant

In this case I want a little unnatural look. Unnatural, but not looking unnatural, if you know what I mean.

B

bzareenk

Inspiring

The clarity slider is an excellent tool for adding punch to images without making them look unnatural. The secret is to get all your primary corrections done first, exposure, color, highlights and shadows but not to touch the contrast. Keep the histogram within limits and then when happy with the result, slowly add in some clarity, keeping one eye on the histogram. Like any tool push it too far and the result will start to look unnatural but used carefully it can add some real sharpness to even the dullest of shots.

davescm

Community Expert

I don't pretend to know the exact algorithm. But on a practical point, if you want to use clarity in Photoshop, make the layers into a smart object and use Filter - Camera Raw

Dave

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