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Author Topic: Topaz AI Denoise Banding!!  (Read 327 times)

bobfriedman

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Topaz AI Denoise Banding!!
« on: April 20, 2019, 03:57:16 pm »

Used standalone program with a .tif input. Of course, it adds color whether you like it or not.

Nikon D800 ,Carl Zeiss Otus 1.4/55
1/80s f/3.5 at 55.0mm iso5000


after AI Denoise.

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Bob Friedman
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Bart_van_der_Wolf

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Re: Topaz AI Denoise Banding!!
« Reply #1 on: April 20, 2019, 04:06:38 pm »

Used standalone program with a .tif input. Of course, it adds color whether you like it or not.

Hi Bob,

Indeed, that doesn't look good. The color you know already, is caused because the models are not trained on B/W images, but color ones instead.

At what stage did you do the denoising? I'd do it as soon as possible in the workflow (while still in color), before further editing (Clarity and such).

You can also use the "Restore Detail" slider control, but that won't save this situation.

Cheers,
Bart
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bobfriedman

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Re: Topaz AI Denoise Banding!!
« Reply #2 on: April 20, 2019, 04:41:53 pm »

At what stage did you do the denoising?

After some contrast and leveling adjustments.. indeed I gave it an RGB file since I am already familiar with that particular problem which still upsets me.  You can see the color noise in the output quite easily with this one.
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Bob Friedman
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #3 on: April 20, 2019, 04:50:52 pm »

After some contrast and leveling adjustments.. indeed I gave it an RGB file since I am already familiar with that particular problem which still upsets me.  You can see the color noise in the output quite easily with this one.
IF it can't do it's job, maintaining R=G=B (if so) from an original, something is messed up!
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Andrew Rodney
Author “Color Management for Photographers"

faberryman

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Re: Topaz AI Denoise Banding!!
« Reply #4 on: April 20, 2019, 05:04:22 pm »

IF it can't do it's job, maintaining R=G=B (if so) from an original, something is messed up!
It is trained with color images, so when it replaces something in a black and white image, in this case noise, it does so with a color. You then have to change the color space back to black and white, rendering the replaced color as a shade of gray. At least that is how I understand it.

digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #5 on: April 20, 2019, 05:14:47 pm »

It is trained with color images, so when it replaces something in a black and white image, in this case noise, it does so with a color. You then have to change the color space back to black and white, rendering the replaced color as a shade of gray. At least that is how I understand it.
It's trained it seems not to maintain neutral RGB from an RGB working space. What you're basically telling us is that if a color image also have neutrals, expect them not to be neutral after use. That's not a feature, that's a bug. One of the Topaz cheerleaders should contact their engineering and tell them that no, the product shouldn’t do this.  :P
IF the end user after application of the product can desaturate neutrals, (easy), the product should too.
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Andrew Rodney
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Bart_van_der_Wolf

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Re: Topaz AI Denoise Banding!!
« Reply #6 on: April 20, 2019, 06:16:37 pm »

It makes no sense whatsoever to first screwup the relations between R-noise, G-noise, and B-noise, and then let a color noise reduction application try to figure out how to reduce noise, when it's known that that is not how the model was trained.

What does make sense is to let the application remove things like Chromatic Aberrations and RGB noise, then desaturate or use another method to produce a monochrome image.

Cheers,
Bart
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #7 on: April 20, 2019, 07:24:49 pm »

What does make sense is to let the application remove things like Chromatic Aberrations and RGB noise, then desaturate or use another method to produce a monochrome image.
But the product doesn't appear to do that which is not an attractive 'feature'.  ???
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Andrew Rodney
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #8 on: April 20, 2019, 07:30:51 pm »

Image with 'synthetic' colored noise surrounded by a neutral Lstar 50.
Then image after applying Photoshop's 'reduce noise' filter which I will never claim is 'best in class'. But at least it doesn't pollute neutrals afterwards.
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Andrew Rodney
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #9 on: April 20, 2019, 07:35:51 pm »

One more, Noiseware. The bkgnd is still Lstar 50! So yeah, it's possible.....
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Andrew Rodney
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Bart_van_der_Wolf

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Re: Topaz AI Denoise Banding!!
« Reply #10 on: April 20, 2019, 08:00:01 pm »

Image with 'synthetic' colored noise surrounded by a neutral Lstar 50.
Then image after applying Photoshop's 'reduce noise' filter which I will never claim is 'best in class'. But at least it doesn't pollute neutrals afterwards.

Not sure what this is supposed to demonstrate, but noise reduction it ain't !!!
But that may also be due to it not being realistic Image noise, but synthetic noise instead.

Cheers,
Bart
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #11 on: April 20, 2019, 08:02:06 pm »

Not sure what this is supposed to demonstrate, but noise reduction it ain't !!!
But that may also be due to it not being realistic Image noise, but synthetic noise instead.

Cheers,
Bart
The noise was reduced AND the neutrals remained neutral. That's what it demonstrated. Why the Topaz product can't do this, why it introduces a color cast is something Topaz needs to explain.
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Andrew Rodney
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digitaldog

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Re: Topaz AI Denoise Banding!!
« Reply #12 on: April 20, 2019, 09:30:30 pm »

One more example, noisy old 5D, shot at ISO 6400 of Mr. Schewe.
Run through Noiseware. Doesn't use AI which means it doesn't inflect a color cast on the neutral RGB (ProPhoto RGB) image? But it does greatly reduce the noise.
This is a crop at 100% (1:1) from Photoshop.
Maybe Topaz or cheerleaders can explain how they shift neutrals and why that's a feature.  ;)
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Andrew Rodney
Author “Color Management for Photographers"
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