This is not a complaint, but am looking for info so I better understand what is happening within Acorn (and eventually the other software).
Here is what I am seeing -
I have a full-frame camera that produces 40+ mb files. I work with Lightroom to organize and prep my images, before exporting to JPG files. An example exported file is 37.7 MB in size; by simply opening in Acorn and hitting save, this drops to 20.5 MBs in size.
Is there a reference file/documentation on what is happening and how Acorn handles jpg files (preview, metadata, etc.)?
So when you save a file as JPEG, it’ll compress the image so it’s not as big as it would be if 100% of the pixel data was present (like in a PNG, TIFF, or Acorn image)
JPEG is a “lossy” format, meaning it’ll throw out parts of the image to make the file size smaller. And you can control how much is thrown out with a Quality/Compression slider usually. Acorn has one in its Save and Export windows.
The more compression, the lower the quality.
When you’re saving an image out of Lightroom as a JPEG, it’s probably setup to use a higher quality / lower compression setting for the JPEG.
In Acorn, when you save a new image as a JPEG (or use Save As…), Acorn will use whatever you pick in the slider. And for automatic saves, it’ll remember what you used previously. By default, the quality value is at 90%, which will make a relatively large file.
For metadata, Acorn will write back out what it has read in. If you use the Export (Web & Other)… menu item, then you can uncheck the box which says to save the image metadata.