Yep the ever pressing question asked a thousand times answered a thousand and one ways! I have question 1001 ! lol… So I do alot of post processing creating very large image sizes… sometimes over 1GB.. I know I can compact this or whatever you do when I save out of photoshop.. ( will have to revisit this) But also if the largest size I can upload to shootproof is 50mb i assume thats enough to print a very high quality print thats say 16x20 or is that more into what my dpi or pixel image is 300dpi or 3000 pixels .. if 300 pixels is the most you can have,, I am soooo confused with image size and printing vs web and keeping the size of the original image itself especially when cropping and then you lose important parts of the image,,, I need to find a course on this subject itself… I just shoot and edit and dont think about print I assume it just all fits...lol.. WRONG. Any advice The struggle is real.
Best answer by AnneSimone
First, let’s talk about pixels:
Every camera produces an image with a native size. For example, the Canon 6D Mark II produces a photo that is 6240x4160. If you export that image at 72 pixels per inch, it will be 86.67” wide by 57.78” high. If you export that same image at 300ppi (ideal for printing) it will be 20.8” wide by 13.87” high.
The total number of pixels in the overall image remains the same: 6240x4160. All that has changed is how many of those pixels you’re packing into an inch.
On the standard computer monitor, photos are displayed at approximately 72ppi. So it doesn’t matter how YOU set the exported JPG’s resolution; that photo’s pixels will cover the screen’s pixels at a 1:1 ratio. That’s why, if you view a straight-out-of-camera picture in Lightroom at 100%, it will be much bigger than your computer screen.
Now let’s say that you want to print a 30”x20” photo. You totally can, BUT the native print size at 300ppi is only ~21”x14”, as we reviewed above, right? So when you crop or export that file into a 30”x20” at 300ppi, your software will have to essentially split your pixels to fit that print size. This is why the quality of the photo begins to diminish as you make it larger and larger.
So, the overall is simply that pixels-per-inch doesn’t really matter. It’s the total number of pixels that matters.
Now let’s dig into file size:
As for the file size itself—the number of megabytes—all that indicates is how much information is being stored. When you first import your images onto your computer, those RAW files contain TONS of data, making them (in this example) about 26mb each. After you edit those photos, the file sizes will change according to how much date was removed in the editing process. And when you export that photo from Lightroom at 100%, you’re saving LOTS of info—frequently way more data than our eyes can even see. That’s why professional print labs will recommend that you send them files that you’ve saved as Standard 10 quality JPGs: because that’s approximately the amount of data we can actually see. And the file size is DRAMATICALLY smaller when you strip out that unnecessary data, which means the lab’s servers aren’t bogged down.
And if you export your Lightroom JPGs at 80% quality, you’ll achieve the same thing: you’ll strip out only the unnecessary data and make the file size much smaller—all while the number of pixels remains the same.
The same is true if you save your Photoshopped files as Standard 10 JPGs. The quality won’t be visibly any less, but the file size will be MUCH smaller.
(This is a version of what software like JPG Mini does, making your photos way smaller in megabytes without making them smaller in physical size.)
This Help article may also be beneficial: https://help.shootproof.com/hc/en-us/articles/115009451147-What-is-the-ideal-file-size-
I hope all of this makes sense!