Hope someone can assist. Have been trying to blend bracketed photos to create a HDR for processing for architectural photography. Playing around, I added the Grey copy layer to all the photos with results being far from acceptable. Playing around with differnt colour adjustments applied to the layer mask to limit the mask selection to the areas I want as a priority, tried the curves tool with results not working, the levels slider works fairly well but found if i set all the masks to 100% brightness i get a fairly flat file with detail. I am happy with the result but have no idea why this works in this way. Can someone explain and help. Is there a better option to adjust the mask for luminance values when doing the exposure blending? If this method works well is there a way to speed this up with automated key strokes? Importing with Raw therapy after denoising and lens correction done with DXO pure Raw.
I have never done HDR blending in GIMP except once experimenting with luminosity masks. I am not a huge HDR fan as I usually get better results from one single RAW exposure using darktable. Darktable also offers a HDR feature which might be of use to you if you want to try that.
But if you want to persevere with GIMP for this hopefully this link for luminosity masks will prove helpful.
https://www.chuckhenrich.com/gimp-interactive-luminosity-masks/