Advice with Auto Balance Black White Widget in Batch Workflow

Moderator: jsachs

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solaranamnesis
Posts: 3
Joined: March 31st, 2021, 4:05 pm

Advice with Auto Balance Black White Widget in Batch Workflow

Post by solaranamnesis »

Hi All,

I am a big fan of PWP and have been using the latest version of PWP to batch convert dozens of images via the batch workload process. Now my question concerns the Auto Black and White Balance widget. I stitch all the images together into a giant mosaic. And the issue arises when most of the images contain large quantities of nearly black RGB colors. When I stitch them the result is a patchwork of different "shades" "intensities" of black/gamma which is hard for me to explain. It is noticeable in the darker images (especially with high backlight displays): https://www.flickr.com/photos/solaranamnesis/

Does anyone know how to ensure that a batch edit on the Auto Balance Black and White results in a set of images which can be stitched so that no differences can be seen?

Thanks,
Solar Anamnesis

jsachs
Posts: 3234
Joined: January 22nd, 2009, 11:03 pm

Re: Advice with Auto Balance Black White Widget in Batch Workflow

Post by jsachs »

Generally when taking pictures and planning to stitch them together later you set your camera on manual and use the same camera settings for all the images and then you process them all identically.

Auto Black and Auto White are not guaranteed to make multiple images consistent.

You could try using the Autorange transformation and playing with the Black Threshold slider, but whether or not this works depends on the images. Without seeing the original images it's hard to recommend a procedure.
Jonathan Sachs
Digital Light & Color

solaranamnesis
Posts: 3
Joined: March 31st, 2021, 4:05 pm

Re: Advice with Auto Balance Black White Widget in Batch Workflow

Post by solaranamnesis »

Thanks jsachs for your reply. For the images they are taken under a manual exposure, identical settings and exposures for each. They are then focus stacked with Zerene Stacker. It might be the case that Zerene Stacker could be issue.

Attached a screenshot showing the issue (the difference has been exaggerated). Some individual image squares can been seen.
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GIMP Screenshot
GIMP Screenshot
Screenshot from 2021-03-31 10-19-54.jpeg (166.35 KiB) Viewed 392 times

jsachs
Posts: 3234
Joined: January 22nd, 2009, 11:03 pm

Re: Advice with Auto Balance Black White Widget in Batch Workflow

Post by jsachs »

My recommendation is to do as little to the image files before stitching as possible. First make sure your raw converter is not making any automatic exposure adjustments. If you are working from JPEGs, that could be the problem as they are processed in-camera and there may be variations in the processing among the images. As long as you used the same lighting and camera settings, the stitch should not show brightness variations. Also consider stitching before focus stacking. Only when all that has been done, open the image in Picture Window and start making adjustments.
Jonathan Sachs
Digital Light & Color

solaranamnesis
Posts: 3
Joined: March 31st, 2021, 4:05 pm

Re: Advice with Auto Balance Black White Widget in Batch Workflow

Post by solaranamnesis »

Yes, that makes sense. I will take this advice into consideration for my workflow, thanks again jsachs!

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