RAW to PSD = massive file size difference, why?

Forum|Forum|3 years ago
January 4, 2023
2 replies
1649 views

Why are my ARW files at 59MB turning into 172MB size files when I simply export from camera raw at 8 bit Adobe RGB at same dimensions and resolution? Thanks for any help.

Windows

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Correct answer D Fosse

The main explanation is that a raw file is a single channel, while the RGB file has been demosaiced and encoded into three channels. So that triples the size right there.

Then there are other minor factors, but mainly it's the number of channels.

M

Mariam Hovhannesyan

Community Expert

Here is some answer that I found on web.
Hope this can help

"First of all, size in MB doesn't directly mean anything for print production. Resolution means everything.

When you open raw image in Photoshop, it saves in memory not only raw image itself, but also a copy of the image that you made while import with Camera Raw, so, basically you have original and Camera Raw version of the image in memory. That's why the size is approximately double.

When you save psd file, if you save it with support for previous Photoshop versions, file size can grow up dramatically. So if you don't need support for previous versions of Photoshop, always remember to uncheck that option upon saving.

If you want to keep your files in raw, I suggest you to use Digital Negative (DNG) file format. It's native for Adobe and in the same time uses losless compression."

D Fosse

Correct answer

Community Expert

The main explanation is that a raw file is a single channel, while the RGB file has been demosaiced and encoded into three channels. So that triples the size right there.

Then there are other minor factors, but mainly it's the number of channels.