JPEG XL - poor image quality/compression

[Alex_M]

I've noticed that my exported JXL images have poor quality for their file size. If I use the official JPEG XL encoder (version 0.70), I can get much better quality for the same file size.

Please check the examples attached.

BTW, why is there no option to pick the compression strength (AKA "effort")? There's only a quality slider. This is an important part of the encoder and should be exposed as an option IMO. Maybe the reason why the Affinity Photo exported JXL images are of poor quality for their file size is because it uses a very low compression strength by default?

affinity_photo_JXL_quality-37.jxl JXL_0.70_quality-66_effort-7.jxl

[MikeTO]

Hi Alex, I don't know much about JPEG XL but since nobody else has replied yet but several have downloaded the images you attached, it might be good if you could upload the original photo prior to exporting in afphoto format. That would allow somebody to duplicate the conversion to jxl in another app and compare the quality.

Cheers

[NathanC]

Hey @Alex_M apologies on the late reply,

I've just exported a .JPG using the latest encoder build (0.81) without specifying any additional parameters and then exported the same image from Photo 2 using the same image and the 'Best Quality' preset, in terms of overall image quality the two .JXL files appear to be identical.

Perhaps this is related to the lack of an 'Effort' setting within export settings which the encoder offers which has caused the difference in overall quality.