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defaultkw36ey3mo8yh
Participant
September 2, 2021
Answered

B&W files exporting smaller than color images

  • September 2, 2021
  • 3 replies
  • 272 views

Hi! I recently imported some files into Lightroom and made a copy of each so I had two identical collections. One collection I edited in color and the other as B&W. I exported each collection with the same settings - JPEGS at the highest quality (these are for print). I noticed that the color exports are several megs larger than the B&W exports. Does anyone know why this happened and how to prevent it? Thank you in advance!

This topic has been closed for replies.
Correct answer JohanElzenga

B&W images will compress much better than color images, even if the B&W images are still in RGB and not in greyscale. That is because 8 bits allows 256 shades per channel, so color images can have 256x256x256 colors, while B&W images will only have 256 shades of grey. So this is completely as expected.

 

3 replies

JohanElzenga
Community Expert
JohanElzengaCommunity ExpertCorrect answer
Community Expert
September 2, 2021

B&W images will compress much better than color images, even if the B&W images are still in RGB and not in greyscale. That is because 8 bits allows 256 shades per channel, so color images can have 256x256x256 colors, while B&W images will only have 256 shades of grey. So this is completely as expected.

 

-- Johan W. Elzenga
    cmgap
    Community Expert
    cmgapCommunity Expert
    Community Expert
    September 2, 2021

    Can you post a screen shot of your export window settings for both color and B&W?

    dj_paige
    dj_paige
    Legend
    September 2, 2021

    Ignore megabytes of exported photos. These are meaningless, and do not indicate quality. JPG is a compression technology, and it is not unusual for different photos to export at different megabytes, because they compress differently. 

     

    So how to prevent it? You can't, and as stated, its not a problem when it happens.

     

    D
    defaultkw36ey3mo8yhAuthor
    Participant
    September 2, 2021

    Oh great to know! Thank you! 

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