Tif rec.2020 import for HDR transfer, How to enable 32-bit Preview

[webdove]

Hi,

I found the only way to export a DxO Wide Gamut for use in affinity is by using Tif 16-bit and the Rec.2020 color space.

The image stemmed from a Raw Sony A7RV camera. No modifications were performed in DxO, only export.  DxO was using the DxO Wide Gamut internal colorspace.

Affinity appears to have imported the image properly. The header says RGBA/16 - Rec.ITU-R BT.2020-2 and the colors look similar to the DxO app colors.

However, I cannot engage 32-bit preview. I have an LG OLED CX and Nvidia RTX 3080ti.

If I load exr or raw or jxl images using Affinity Photo 2 I can enable 32-bit Preview, but DxO cannot export in those formats.

How can I get affinity to switch to a 32-bit Preview if it has loaded a valid 16bit RGB image which is defined in a wide-gamut color space?

 

Thanks

Web

[walt.farrell]

20 minutes ago, webdove said:

How can I get affinity to switch to a 32-bit Preview if it has loaded a valid 16bit RGB image which is defined in a wide-gamut color space?

32-bit Preview will require a 32-bit image (e.g., RGB/32). Can DxO handle that as an output format?

[webdove]

It does not appear so.

[walt.farrell]

In that case I don't think you'll be able to do what you want, but I suppose you could try using Document > Convert Format in Photo to change your RGB/16 document to RGB/32 and see if that helps.

[webdove]

Gimp is able to import the 16-bit tiff and export exr or jxl which affinity likes, but they seem to have different color profiles.

 

[webdove]

I did the convert to RGB/32, that seemed to reduce the saturation a lot.  I wonder why.

 

Edited August 7, 2023 by webdove

[walt.farrell]

[NotMyFault]

Can you explain why you want to use 32 bit preview for RGB/16 images?

it allows to render lightness values larger 1, which are not possible with any other color format except RGB/32. So the image should not look „better“ in any way if converting/switching to RGB/32. In Affinity, you can handle color profiles separately from bit depth - so no need to use HDR.

but on the flip side, the major difference between color formats is gamma curve, which totally alters the image rendering. When using RGB/32, you need at least to activate „icc“ in 32 bit preview which then applies a gamma correction for rendering, so you get a rendering which mimics that of RGB/16 images.

 

[webdove]

Ah.  I restarted and set my HDR Calibrated Profile as the windows default. The monitor is in HDR mode.

I was able to export DxO as 16-bit tif and prophoto RGB colorspace.  Then I imported it to affinity and changed the format to RGB/32 and the colors were preserved properly relative to their appearance in DxO.

 

[webdove]

I wanted to look at the original 14bit image from the camera which is wider gamut than sRGB.

[webdove]

How do you quote another message within a reply in this forum app?

[webdove]

My one remaining puzzle is how to convert any of the export HDR forms in affinity to avif which is the only form that can be viewed with a browser.  ImageMagick sounded like a possibility, but that failed.

[NotMyFault]

4 minutes ago, webdove said:

How do you quote another message within a reply in this forum app?

There is a button labeled "quote" right to the "+" button below every post.

[R C-R]

1 hour ago, webdove said:

How do you quote another message within a reply in this forum app?

Besides using the Quote button at the bottom of each post, depending on the browser you are using, you should be able to select (highlight) some of the text in a post, which pops up a "Quote Selection" button. This is useful if you do not want to quote an entire post, like I did below to quote just a part of what @NotMyFault wrote in an earlier post.

10 hours ago, NotMyFault said:

Can you explain why you want to use 32 bit preview for RGB/16 images?

 

[webdove]

I just noticed something else.

Export exr uses 8bits/color, webp uses 8bits/color, jxl uses 32bit float/color. So only jxl preserves the image quality fully.

I checked using irfanview so I could see the detailed properties of the files.

Edited August 8, 2023 by webdove
additional information

[webdove]

Hmm.  Gimp reports differently

DxO tif export source image is 16-bit gamma integer.

exr export is 32-bit linear floating point.

hdr is 32-bit linear floating point.

jxl is 32-bit linear floating point.

webp is 8-bit gamma integer.

avif (converted with ImageMagic from jxl) is 16-bit gamma integer.

I guess I would believe gimp over irfanview.