file size

[photojenic06]

I am hoping someone can help me!
I import an image in LR that is raw and is about 11 mb
when I export the image shrinks to 2.5 mb ( approx )
my settings are at 300 dpi and 100 percent when I export
what am I doing wrong ?

 

[Mark Sirota]

Are you exporting as a JPEG? A JPEG is inherently smaller -- it is only 8 bits of color depth, and features compression (even at Quality 100).

PPI (not DPI) has nothing to do with the size -- it's just a metadata tag in the exported file.

 

[photojenic06]

ahhh ...that makes sense
Thank you

 

[b_gossweiler]

Also, as an add-on to Marks explanation, be aware that the size of a JPEG varies heavily depending on the degree of detail in your photo. Images with a lot of detail (i.e. a lot of noise, fine image details) can be compressed less than images with less detail (i.e. just a blue sky).

Beat

 

[tzalman]

A JPEG is inherently smaller -- it is only 8 bits of color depth,

Umm, no. It's 24 bits.

 

[Brad Snyder]

Well, that's splitting the hair awfully fine.....

 

[Mark Sirota]

Umm, no. It's 24 bits.

Splitting hairs, definitely. I don't think it's wrong to call it 8 bits of color depth -- there are 8 bits per channel, three channels per pixel, 24 bits per pixel altogether. I think we both knew what I meant, whether or not you agree with the terminology.

 

[clee01l]

Umm, no. It's 24 bits.

Actually 3X8 bits per channel. 24 bits per pixel (eight each of red, green, and blue). Commonly referred to as 8-bit. But only if you want to get pedantic.

 

[b_gossweiler]

Also, LR (i.e. in it's export dialog) refers to bit depths as 8 or 16, not 24 or 48.

Beat

 

[Victoria Bampton]

While this is a fascinating discussion in semantics, I think it's probably more than the OP needs to know...

 

[tzalman]

It's not splitting hairs when the OP's question was regarding file size and Mark's reply was that one of the causes of the smaller jpg size relative to the RAW file, other than compression, is bit depth. An RGB jpg has 24 bits of data and everyone of those bits contributes to the file size. The smaller jpg file size is entirely because of compression and, with all due respect, Mark, your answer could have led the OP or others to assume that an "8 bit" tif should also be smaller than an 14 bit RAW.

 

[clee01l]

It's not splitting hairs when the OP's question was regarding file size and Mark's reply was that one of the causes of the smaller jpg size relative to the RAW file, other than compression, is bit depth. An RGB jpg has 24 bits of data and everyone of those bits contributes to the file size. The smaller jpg file size is entirely because of compression and, with all due respect, Mark, your answer could have led the OP or others to assume that an "8 bit" tif should also be smaller than an 14 bit RAW.

I believe the word I used was "pedantic". And BTW in my math 14bits of color per channel is bigger than 8 bits of color per channel.

(And I do hope the OP was done at Post #3)

 

[tzalman]

And BTW in my math 14bits of color per channel is bigger than 8 bits of color per channel.

Indeed it would be if LR could export single channel images.

 

[Kiwigeoff]

Let's just let this go and resume our normal friendly service and refrain from semantic debates - the OP has been satisfied and if you want to further the discussion, the lounge is the place.

Thank you.:focus: