If you can, please share one such strip or a part of one so that I can show you how you can do everything in G’MIC CLI alone.
PS Here is a quick example.
1 I took your image and cropped a section of the strip from your first screenshot.
2 Used the following G’MIC command.
gmic fs.jpg +crop 0,0,100%,35% adjust_colors[1] 0,25 image[0] [1] remove[1] split x,7 output fs.jpg
Let me break it down for you:
a fs.jpg A file name by itself inputs the file into the G’MIC image buffer. Since it is the first image, it will be assigned to [0].
b +crop The + makes a copy of the image. This image will be assigned to [1]. Crop is a command that takes parameters. In this case, x0,y0,x1,y2; in other words, I am only cropping the bottom and keeping 35% of the top. This is the area you want to increase the contrast.
c adjust_colors[1] The first parameter is brightness and the second is contrast. We only want to adjust [1].
d image[0] [1] This one is a little more abstract. Basically, you are modifying image[0] by placing image[1] on top of it.
e remove[1] After that step, you don’t need image[1] anymore, so you remove it.
f split x,7 Next you want to split the only image left into 7 parts horizontally (x). You need to start with a good crop of the filmstrip. Otherwise, the segments won’t be evenly distributed.
g output fs.jpg And finally output it. Notice the output file name is the same as the input’s. Typically, this would overwrite the original, but since you have multiple images in the buffer now because you split it into 7, the naming will become fs_000000.jpg all the way to fs_000006.jpg
h That is only for one slide. However, you can place that code into code like this to make it iterate over all your images.
gmic input_glob *.jpg repeat $! local[$>] ...what_you_want_to_repeat... endlocal done
Read the documentation for more insight:
https://gmic.eu/reference.shtml
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