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Banding problem when converting to 16 bit or 8 bit RGB


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I was working an HDR image that looks perfectly fine in 32 bit HDR but when I convert it to 16 bit LAB or 8 bit RGB I am getting a banding problem.
My banding problem is occurring in a storm photo I took in which I combined 3 exposures in 32 bit HDR.

The banding appears in the smoother areas of the dark clouds in the photo.

Like I said this banding is not visible with the original AP document that is in 32 bit HDR.

The banding is only noticeable when converted to a 16 bit LAB color TIF file or an 8 bit RGB JPEG.
I did not have this problem with the last version of AP so I am wondering if it is a problem with the way the newer version of AP is converting the image to the other formats I use.

I am including the JPG version that has the banding.

The only way I have been able to fix this is by lightening the tones of the clouds where the banding occurs, but that ruins the HDR toning, so I hope there is a fix because I do a lot of HDR photography.

I am using the latest version of AP (1.8.4)

FSR492-StormOverMatterhornMesaAZ-36MP.jpg

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The problem arises when you have large areas of a single hue with various shsdes. In your case, you have many shades of grey in your clouds. Grey is represented by all three channels  being the same, so, in 8-bit, you have a maximum of 256 shades of grey. The conversion from 32 or16bit grey to 8-bit does not always produce sufficiently smooth gradations, leading to banding.

Did you convert directly from 32-bit to 8-bit? Or 32-bit to 16-bit to 8-bit? The latter may give a smoother result than the former.

John

Windows 10, Affinity Photo 1.9.2 Designer 1.9.2 and Publisher 1.9.2 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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3 hours ago, John Rostron said:

The problem arises when you have large areas of a single hue with various shsdes. In your case, you have many shades of grey in your clouds. Grey is represented by all three channels  being the same, so, in 8-bit, you have a maximum of 256 shades of grey. The conversion from 32 or16bit grey to 8-bit does not always produce sufficiently smooth gradations, leading to banding.

Did you convert directly from 32-bit to 8-bit? Or 32-bit to 16-bit to 8-bit? The latter may give a smoother result than the former.

John

When I work on these type of images I first shoot the scene in Camera RAW, in my case it is a Nikon D810 set to NEF raw.
I then open the NEFs with AP and do the development. I have AP set to open the NEFs in 32 bit RGB HDR, which preserves 100% of the original NEF quality while I do the development.

When all the development is done I then save the file as an AP document preserving the 32 bit RGB quality. I then use that as the master copy which I use to produce a 16 bit LAB TIF file for printing and an 8 bit RGB JPEG which is for uploading to the stock agencies I sell my work through.

I forgot about the 256 shades of gray limitation for JPG images.
But I can see the banding to a smaller extent in the 16 bit LAB TIF file, which has not occurred before.

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Hi,

I have a similar problem where when I export I lose some fine shades from black to gray in my images, and I do not know if I do something wrong at exporting or is the limitation of the file format (JPEG/PNG/TIFF). I have attached my Affinity Photo (ver 1.8) project and the JPEG I exported. The area in question is on the two lamps above the drinks.
Would really appreciate any help you can spare ❤️ 

Stay safe!

Edit: I have exported the image in JPEG format and embedded my display's ICC profile and it looks fine, but I do not think I should do it, if I remember correctly I should embed sRGB standard ICC profile right? I have also attached the custom ICC JPEG as well.

DSCF2205.jpg

DSCF2205_custom_ICC.jpg

DSCF2205.afphoto

Edited by Daniel Tudosiu
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1 hour ago, Daniel Tudosiu said:

Hi,

I have a similar problem where when I export I lose some fine shades from black to gray in my images, and I do not know if I do something wrong at exporting or is the limitation of the file format (JPEG/PNG/TIFF). I have attached my Affinity Photo (ver 1.8) project and the JPEG I exported. The area in question is on the two lamps above the drinks.
Would really appreciate any help you can spare ❤️ 

Stay safe!

Edit: I have exported the image in JPEG format and embedded my display's ICC profile and it looks fine, but I do not think I should do it, if I remember correctly I should embed sRGB standard ICC profile right? I have also attached the custom ICC JPEG as well.

DSCF2205.jpg

DSCF2205_custom_ICC.jpg

DSCF2205.afphoto 311.93 MB · 0 downloads

If you're converting from 32 bit RGB to 8 bit RGB JPG, like the way I was, it is a limitation of the file format you're converting to, especially if it looks normal in 32 bit color.
Like I mentioned in my posting I only encounter this problem when photographing cloudy sky with a lot of bluish grays, and I have also encountered this problem with blue skies that have gradually changing shades from light to dark.
I was only able to solve the problem by lightening up the darker areas before converting it to a JPG.

However, I always save a master copy in 32 bit color just in case AP releases a newer version in the future that might have better compression when converting.
 

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