File size after heavy cropping

[solway moss]

Alan, thank for SoLD explanation. 

 

I am now juggling my crops using pixel dimensions as guide to file size in MB's before exporting as jpeg. Your book analogy is a good one.

 

Here is what Lightroom Forum says:

 

"I don't think there's anything in Lightroom that would help determine how large a cropped image would be after export, all you have is the original file size and the cropped pixel dimensions, nor is there anything suitable in the Export module (you can tell Lightroom to make sure a file is no smaller than a specified size, but you can't tell it to make sure the file is at least as big as a specified size). Might be a useful feature request, if it hasn't already been made."

[Inchiquin]

Just forget about the file size. It's not really relevant at all in this situation. All you need to know is the width and height of the image in pixels. The image size is not quite width x height x 3 because a megabyte is 1024 bytes, not 1000. So the calculation is width x height x 3 /  1.05 or thereabouts - just make it a bit bigger than that to be on the safe side.

 

Alan

[solway moss]

Perfectly clear, thank you.

[skylineboy]

What is SoLD ?

 

It is too small and will need resizing to at least 24MP. In LR, exporting at 5000px on the long side will do as long as the aspect ratio is preserved.

 

Upsize from 2496 to 5000 will no doubt introduce SoLD. It's not going to pass QC. Don't do it!

 

[solway moss]

I know! And I haven't. Using Alan's formula - height x width x 3 divided by 1024 gives me number of MB's. If height x width equals at least 8,500,000 pixels, I'm safe I think!  This is for an 18MP camera.