bug in Affinity Photo Develop Persona turns blown out parts into magenta after reducing highlights

[Dirk Staut]

Recently I started using DXO Deep Prime to reduce noise in my RAW files (when shot at high ISO). The software of DXO opens the RAW file (in my case Canon CR2 files), does a fantastic job in reducing noise and primary sharpening and saves the file in DNG format. When I open this DNG file in Affinity Photo the Develop Persona allows me to reduce hightlights as well as other RAW adjustments. However reducing the highlights will change all blown out parts of the DNG image into magenta. After opening the image in the main Photo Persona these blown out parts of the image remain magenta. As the highlights can not be reduced without the magenta colorisation of the blown out part, the resulting image in the main Photo Persona is useless. However it should be noted that opening the original CR2 file in the Develop Persona and reducing the highlights does not result in magenta colorisation.

I checked of this bug is typical for Affinity Photo by repeating the above process in Adobe Photoshop. When I open the DNG file in Adobe Camera RAW the highlights in the image can be reduced (to -100%) and the blown out parts of the image remain white. They do not turn magenta. Based on this comparison it seams there is a bug in the RAW processing in the Develop Persona in Affinity Photo resulting in the unwanted magenta colorisation of blown out parts is a bug in the DNG file.

To illustrate the above I have included my CR2 file as well as the DNG file (resulting from processing in DXO Deep Prime) and some screen shots from the RAW conversion and highlight reduction in both Affinity Photo and in Photoshop.

Can someone please look into this bug in the RAW conversion persona of Affinity because apart from this bug I prefer using Affinity Photo and not using Photoshop. 

DRCStaut_20200905_IMG_4348-CR2_DxO_DeepPRIME.dng DRCStaut_20200905_IMG_4348.CR2

[Lem3]

Similar issue reported with DNG files from DxO PureRAW, as yet unresolved:

 

[MEB]

Hi @Dirk Staut,
Welcome to Affinity Forums
Thanks for your report. We are already aware of this issue however there's wasn't progress here yet, sorry. I've bumped our log and added your files for testing against new builds/improved code. 

[Affinity Info Bot]

The issue "Develop Persona: issues (highlights rendering) with DNG generated by DxO PureRaw/DeepPRIME technology." (REF: AFP-4444) has been fixed by the developers in internal build "2.1.0.1781".
This fix should soon be available as a customer beta and is planned for inclusion in the next customer release.
Customer beta builds are announced here and you can participate by following these instructions.
If you still experience this problem once you are using that build version (or later) please reply to this thread including @Serif Info Bot to notify us.