Remove too dark photos from batch

Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
salmen
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Re: Remove too dark photos from batch

Post by salmen » 2016-04-18T06:59:05-07:00

Thanks, got the floats working. Now composing one image over another, and use a mask to cover the sky of the second image.

Code: Select all

convert "$file" tempBot.miff "$masksky" -composite -format +repage outcomp2.jpg
There is like a shadow over the sky. Its a bit darker than the original, though there should be no change. what could be the cause?

snibgo
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Re: Remove too dark photos from batch

Post by snibgo » 2016-04-18T07:23:20-07:00

What is "-format" doing there? This is bad syntax: it sets the format to "+repage".

I need to see your input files to comment on the darker sky.
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salmen
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Re: Remove too dark photos from batch

Post by salmen » 2016-04-26T10:05:17-07:00

Not sure what caused the dark sky, but now its working.
Is it feasible to use dng-files directly? Would be less files to keep track of and possibly some win in quality? But alot slower, and to look good the dng-files need some values applied. Possible to edit dng in lightroom or darktable and use those values?
Maybe easier to export jpg/png/tiff and work on those files, right?

snibgo
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Re: Remove too dark photos from batch

Post by snibgo » 2016-04-26T12:58:50-07:00

You should certainly use dng files rather than jpegs as your sources. They will need demosaicing and converting to sRGB, possibly resizing, possibly with no other processing. If you do any processing such as adjusting levels, you probably want to ensure exactly the same processing is applied to all the frames.

You might organise the job so there is only one convert command per frame. As this will include the dng processing, this will be slow. Or you might convert all the dng files to tiff, overnight in batch. This take a load of disk space but will reduce overall time if you need to alter and re-run the processing from the tiff files.

Any sharpening should be done as the final stage before combining frames into a movie.

I suggest you ensure that any intermediate files are at least 16 bit/channel/pixel, not JPEG compressed.
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salmen
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Re: Remove too dark photos from batch

Post by salmen » 2016-04-27T02:33:18-07:00

snibgo wrote:If you do any processing such as adjusting levels, you probably want to ensure exactly the same processing is applied to all the frames.
Thanks, but since there is so much variation in the photos, can you do the same processing?
I was thinking about using Lightroom or similar, apply some auto-adjustment, then output tiff 16 bit/channel and use IM on those. The auto-adjustment (auto-tone) supposedly balances things out a bit. But maybe there is no point in doing auto-correction before applying gain and bias with IM?

snibgo
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Re: Remove too dark photos from batch

Post by snibgo » 2016-04-27T02:58:29-07:00

salmen wrote:But maybe there is no point in doing auto-correction before applying gain and bias with IM?
Exactly. I have shown you a method for auto-correction of tone and colour. It works fine on the small selection of samples you have provided. What other tone/colour correction do you want?

As I mentioned above, you might want to adjust colour saturation and sharpness.
snibgo's IM pages: im.snibgo.com

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