Tutorial for merging multiple long exposure light painting images?

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2022-01-09 18:22:24

I'm trying to figure out the workflow for merging multiple long exposure night shots. I have a few images that contain light streaks from moving vehicles and I'd like to mask them out so that the light streaks from different lanes/locations can all be displayed.

I've attempted to add the images as layers, create a mask, pain in the specific areas, but the I'm not getting the desired effect. Being primarily a Pixelmator Photo user, I'm not as familiar with a lot of the tools used to create masks, which brush settings to use, opacity modes for the layers, etc.

I am also noticing that when I have a brush selected, and I mouse over the tools, or layers, the cursor remains the brush icon which can at times just be a giant circle, making it really hard to be precise when moving sliders or trying to click on other things, is this a setting that can be changed?
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2022-01-12 13:03:05

Could you share the images you're working with? If these are mainly black photos with only light strokes visible, playing around with different blend modes could be an option.
When I have a brush selected, and I mouse over the tools, or layers, the cursor remains the brush icon which can at times just be a giant circle, making it really hard to be precise when moving sliders or trying to click on other things, is this a setting that can be changed?
This one's most likely a glitch of some sort. The cursor should change to a regular pointer once you move it away from the canvas area. Is this happening in every editing session?
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2022-01-12 15:20:08

Here are the 3 original images, and the final that I put together. This was my very rudimentary workflow, but would love some tips on perhaps using different blend modes or any other suggestions.

Add base image as background layer. For this I chose the image that was the most in focus/cleanest.

Added an additional layer on top with 2nd image containing several light streaks that I wanted to show. Added a mask, refine mask, invert mask. Then I essentially picked a brush and erased the mask around light trails.

I repeated this 1 more time with a 3rd image. This time I was smart enough to use the eye dropper selection tool to more easily select the light trails to remove from the mask.

For the blending more I chose "Normal" with 100% opacity. One thing I discovered is that this only really allowed me to include trails from 1 of the 3 images, which worked well in this example because they were in slightly different parts of the image, but I'd also like to know if it's possible to have multiple trails in the same area show through.

I'm not sure if I can add multiple images or not, what's the best way to upload 4?
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2022-01-12 16:12:16

by Aurelija 2022-01-12 18:03:05 This one's most likely a glitch of some sort. The cursor should change to a regular pointer once you move it away from the canvas area. Is this happening in every editing session?
Also wanted to add, after restarting the app this behaviour went away and the cursor returned to normal.
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2022-01-21 17:32:23

by Aurelija 2022-01-12 18:03:05 Could you share the images you're working with? If these are mainly black photos with only light strokes visible, playing around with different blend modes could be an option.

What is the best way to send sample images? I have a recent edit, I believe 4 or 5 images used, and then the resulting Pixelmator Pro file and final output image.

I'm getting a bit better at the workflow, I realized the easiest way to start is to make my selection, then create the mask and it's fairly straightforward, but I'd like to know more about the various blending options, and an auto align feature would really helpful.

For this type of image, because I'm only showing the light trails from all layers except the background layer, the alignment doesn't have to be perfect, but for things like focus stacking auto alignment would critical.

Here's the final output image (I tried to upload an .heic file, doesn't seem like it can be accepted, maybe a bug?)

Image