I’m pretty new to photography (around 7 months in), so I have a general understanding of things like compression, lossy formats, etc., but for the life of me, I can’t figure out the best way to post my photos to Instagram.
I’ve done some research on the max resolution and file size for photo uploads to Instagram, and from what I gather, 1440x1920px and 30MB is the max for a 3:4 photo.
Now, I have some scans of 6x9 negatives I found at a local flea market. I’m trying to add a white border to the edges so I can post the full frame. Here is my process on Photoshop:
Create new file
Width: 1440px
Height: 1920px
Resolution: 72px/inch
Color mode: Grayscale, 8 bit
Background contents: white
Color profile: dot gain 20%
Pixel aspect ratio: square pixels
Then, I save it as a JPEG and set the quality to 12, which gives me a 1.2MB file.
As a test, I saved the original scan as a JPEG at full dimensions (7032x10157px, 29.7MB), then posted both the 1.2MB photo and the 29.7MB photo on Instagram to compare the two. I’ve included screenshots of both Instagram posts. The difference in quality is undeniable. Obviously the 29.7MB photo appears much higher quality. I have no idea why this is happening. Everything I’ve read so far has indicated that the 29.7MB photo would be aggressively compressed and end up looking far worse than a photo that’s under the max size.
Please, can anyone can clarify why this is happening and help me figure out how to add a white border to my photo while maintaining as much quality as possible?
EDIT: As soon as I posted this, it occurred to me that Reddit also compressed images, so the difference in quality between the two screenshots doesn’t appear as stark on here as it does for me.