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Question

File size decreases hugely when exported from lightroom classic.

Forum|Forum|1 year ago
December 21, 2024
3 replies
581 views

Afternoon,

I'm just looking to reach out as this hasnt happened before and I'm not to sure what im doing wrong or whats changed.

My photos I've taken are are over 20mb once imported, edited and exported the files are only 6mb and 6.5mb. They still look fine and everything but it's usually at least double that in size. I'm just wondering if im doing something wrong or missing something.

Thank you

macOS

This topic has been closed for replies.

D

davidminehart

Inspiring

What format were the imported files? What format were the exported
versions? If JPG, the export function has options that affect file size.
The lower the Quality setting (100 is max), the smaller the output file.
There are constraint options, too, on resolution and dimensions (for
instance, setting max dimension to 2048 pixels prevents Facebook from
reworking the whole image to fit).

dj_paige

Legend

You're probably not doing anything wrong. JPG compression does different things to different photos. Exported files 5-6 MB is not unusual or indication that something went wrong. I would recommend you ignore file size.

The real test that you are getting the proper quality is not file size (which should be ignored), but it is what you said: "they still look fine".

Per Berntsen

Community Expert

I'm guessing that your originals are raw files, and that you're exporting jpgs.

The file size of a jpg depends on three factors:

Pixel dimensions
Quality setting used when exporting
Image content

The jpg format uses compression to create smaller files, and the degree of compression possible depends on image content.

Images with predominantly smooth, flat, or out of focus areas will compress well, resulting in a relatively small file.

Images with lots of sharp, busy detail (or noise) are much harder to compress, resulting in a relatively large file size.

The difference in file size can be quite dramatic.

To evaluate the quality of a jpg (or any image), view it at 100%.

100% view is an important reference point – one image pixel is represented by one screen pixel, giving you a true representation of the image. Any other view will be inaccurate and misleading because the image has been scaled.

2048 x 1536, Quality 85, 2.72 MB

2048 x 1536, Quality 85, 448 KB

KR Seals

Community Expert

What is the purpose of the files you are exporting?

What file format are you using for the export? .jpg, .tif, .psd?

Ken Seals - Nikon Z 9, Z 8, 14mm-800mm. Computer Win 11 Pro, I7-14700K, 64GB, RTX3070TI. Travel machine: 2021 MacBook Pro M1 MAX 64GB. All Adobe apps.

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