File size in Lightroom

superpippo

superpippo

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Alan
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I have been attempting of late to shoot in RAW and JPEG fine and trying to draw a comparison.
One thing that puzzles me is that the same picture in JPEG is (one example) 5.99MB yet the JPEG of the same shot exported from the RAW in LR is only 1.95MB, although the image dimensions in pixels are the same.
The only processing done to the RAW image in LR was WB and colour adjustment and a little clarity. The main reason for my experiment was to see how these WB and colour adjustments could improve on the JPEG in difficult mixed light.
Am I doing something wrong in the exporting?
 
superpippo said:
I have been attempting of late to shoot in RAW and JPEG fine and trying to draw a comparison.
One thing that puzzles me is that the same picture in JPEG is (one example) 5.99MB yet the JPEG of the same shot exported from the RAW in LR is only 1.95MB, although the image dimensions in pixels are the same.
The only processing done to the RAW image in LR was WB and colour adjustment and a little clarity. The main reason for my experiment was to see how these WB and colour adjustments could improve on the JPEG in difficult mixed light.
Am I doing something wrong in the exporting?
Click to expand...

The only thing that springs to mind is the "quality" setting in LR, it can be from 0 to 100, 0 been very low quality and 100 maximum quality, obviously the higher the quality the larger the file size.
 
How are you exporting?

The "Burn full size jpeg" export preset is the one that's best suited to this sort of comparison as it doesn't compress the image. If you start specifying dimensions in px, or quality, or filesize, then LR will start mucking about with your image.
 
It’s about quality, or rather compression.

Jpg is lossy and you can chose how much data you want to lose, your output settings in LR apply more compression than the camera is. It’s up to you to decide how much compression is too much but generally LR default options are pretty good.

Edit: to add, the jpg compression you want to apply to your output image will probably be different to a jpg you want to edit, where you want to maintain as much information as possible.
 
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Kiwi Paul said:
The only thing that springs to mind is the "quality" setting in LR, it can be from 0 to 100, 0 been very low quality and 100 maximum quality, obviously the higher the quality the larger the file size.
Click to expand...

Thanks Paul - see below

Harlequin565 said:
How are you exporting?

The "Burn full size jpeg" export preset is the one that's best suited to this sort of comparison as it doesn't compress the image. If you start specifying dimensions in px, or quality, or filesize, then LR will start mucking about with your image.
Click to expand...

Thanks Ian - This option appears to be for burning to cd - which I am not doing, just exporting to my hard drive.

Nawty said:
It’s about quality, or rather compression.

Jpg is lossy and you can chose how much data you want to lose, your output settings in LR apply more compression than the camera is. It’s up to you to decide how much compression is too much but generally LR default options are pretty good.

Edit: to add, the jpg compression you want to apply to your output image will probably be different to a jpg you want to edit, where you want to maintain as much information as possible.
Click to expand...

Thanks Ned

Thanks to all of you for your input.
I tried the suggestion of Paul and it gave remarkable results. One file was processed then exported to the hard drive at qualities of 80, 90 and 100.
The corresponding file sizes on the hard drive became 3.1 MB, 6.5MB and 10.8MB. So that seems to answer my initial query - just a matter of settings.
Although all three image files are the same at 4112 x 3088
But then it raises further questions in my mind.
The LR default quality setting was 79. Scott Kelby in his lightroom book states that generally he chooses quality 80 which he thinks gives a good balance between quality and file size.
The LR default resolution is 240ppi, whereas I thought that the optimum for printing was 300ppi.
If I want to print A3 size is that default quality of 80 and resolution setting of 240 ppi going to give me a good result?
You may appreciate that I do not know a right lot about the interaction of file sizes, resolution, size of image in pixels and printing, :) but as I want to try to print more of my better shots I would appreciate some guidance.
 
If you are shooting and editing RAW, then the only time you need to produce a jpeg is as a 'final image' - at which point chose the quality level appropriate for the use (I usually set it at the highest level that keeps the file within max upload limits).
As far as printing is concerned, if you are printing yourself (rather than sending an image to a printing company), then you can do so from LR, which maintains the maxium quality.
 
superpippo said:
option appears to be for burning to cd
Click to expand...
Yes. You're right. MIssed that. Just go into Export and change the "Export To" location from DVD to "Hard Drive" then set the location to (for example) your desktop. This will output the image as a full size jpeg at 100% quality. I'd also click the "Add" button and create it as a new preset called "Export FullSizeJpeg" to save time next time you need it.

superpippo said:
I want to print A3 size is that default quality of 80 and resolution setting of 240 ppi going to give me a good result
Click to expand...
A3 is 11.7" x 16.5". At 240 ppi, this will require a file that is 2808 x 3960. Your post states images that are 4112 x 3088, so this will be fine. For info, 300ppi needs a file that's 3510x4960 which yours isn't - but you can let Lightroom interpolate (enlarge) the image for you. As it's only a small increase, it should be fine. If you divide your sensor size by the image size, you get the perfect resolution with no enlargement. e.g. Your sensor/image is 4112 x 3088 so this would be roughly 250ppi without LR mucking about with the image. The Print module is tailor made for figuring all this out for you (rather than the export function) and if you're not printing yourself, you can print to jpeg too.

superpippo said:
he LR default quality setting was 79. Scott Kelby in his lightroom book states that generally he chooses quality 80 which he thinks gives a good balance between quality and file size.
Click to expand...
I'd leave the quality at 100% unless you have some sort of file size limitation somewhere? Does he state in the book if that relates to internet use? For screen display, you can really hack the size and quality down without any visible effect, but I would never do that for print - especially a large print.

superpippo said:
The LR default resolution is 240ppi, whereas I thought that the optimum for printing was 300ppi.
Click to expand...
300ppi is given as the optimal size for printing because 300ppi is about the best that the human eye can resolve at a distance of 12" (typical magazine reading distance). Move to 30" (standard monitor distance) and the best the human eye can do is 115ppi. You rarely need 300ppi for large prints because you're going to be looking at them from a distance. But if you *can* get high resolutions on large prints - why not? You just don't always *need* them.

Hope this helps (rather than confuses)
 
superpippo said:
The LR default resolution is 240ppi, whereas I thought that the optimum for printing was 300ppi.
If I want to print A3 size is that default quality of 80 and resolution setting of 240 ppi going to give me a good result?
Click to expand...
Harlequin565 said:
300ppi is given as the optimal size for printing because 300ppi is about the best that the human eye can resolve at a distance of 12" (typical magazine reading distance). Move to 30" (standard monitor distance) and the best the human eye can do is 115ppi. You rarely need 300ppi for large prints because you're going to be looking at them from a distance. But if you *can* get high resolutions on large prints - why not? You just don't always *need* them.
Click to expand...
This is good advice.

Just to add though - if you've specified the export size in pixels, or if you haven't resized it, then the ppi figure is meaningless. It's just a number which is written into the metadata but is nearly always ignored. So an image that is 4112 x 3088 at 240 ppi is the same as an image that is 4112 x 3088 at 10 ppi - it's the pixel dimensions that matter.
 
StewartR said:
So an image that is 4112 x 3088 at 240 ppi is the same as an image that is 4112 x 3088 at 10 ppi - it's the pixel dimensions that matter.
Click to expand...
Only for screen display... ppi does come into consideration when printing.
 
superpippo said:
But then it raises further questions in my mind.
The LR default quality setting was 79. Scott Kelby in his lightroom book states that generally he chooses quality 80 which he thinks gives a good balance between quality and file size.
The LR default resolution is 240ppi, whereas I thought that the optimum for printing was 300ppi.
If I want to print A3 size is that default quality of 80 and resolution setting of 240 ppi going to give me a good result?
You may appreciate that I do not know a right lot about the interaction of file sizes, resolution, size of image in pixels and printing, :) but as I want to try to print more of my better shots I would appreciate some guidance.
Click to expand...
The optimum print resolution depends on how far away the viewer is. With A3 the viewer is further away than they would be for A4. That means that a lower print resolution would actually look the same. The print resolution setting is almost meaningless. If you have a file from a Canon EOS 80D the image will be 6000 by 4000 pixels. If you set the print resolution to 300 pixels per inch and print at 10inches on the long side, you will get 600 pixels per inch, not 300.
 
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