File sizes

[calaf]

Probably a simple question, but..

I generally shoot sRGB. The file size is in the region of 4.5MB.

When I edit in Lightroom and then export it to edits, I see, with limited changes in the editing, the file size drop to less than 1MB.

Have I missed something totally obvious?

Thanks in advance
Chris

 

[Brad Snyder]

Chris, sRGB doesn't really matter. Of more importance are the file types, both imported and exported.

Thinking further about this, perhaps you mispoke, and were thinking JPG, instead of sRGB when you were typing.

The spec sheet on the 4'D calls for a 3.5 MB for the Large/Fine JPG.

If you're getting much smaller JPGs exported, possible explanations are

1) Cropping. In an export, cropped areas are simply discarded, reducing file size.
2) Noise reduction. This can have a huge effect. Noise pixels are inherently un-compressible as they are indistinguishable from real data. If you've applied NR, you can expect substantial filesize reductions.
3) Downsampling. If you've made setting changes in the 'File Resizing' panel in Export, that will also have drastic effects on the exported file size.
4) Export Quality. This trades off image detail preservation against file size.

Tell us more about the workflow for a given image, and we can home in a little closer on the specific issue.

 

[calaf]

Brad

Thanks as ever for a prompt reply.

Looking again, I am seeing a variety of file sizes in the original jpgs (shot using sRGB, )
The Canon is set to large jpg. There are files that are in excess of 5 MB, but these are the original files.
My way of doing things, and I accept that there are probably much better routes, but one gets into particular ways, is, once I have edited the images, often for the work website, to export them to an edits folder. This means that I can upload them more quickly. (The website has the facilty to reduce files to web friendly sizes so I don't do that.)
Looking in that folder I am now seeing the 5''-6''KB files sizes I mentioned.

To clarify the issues you raise:
1) Cropping. Often cropped, but I do try to reduce crops to minimum

2) Noise reduction. Rarely use

3) Downsampling. If you've made setting changes in the 'File Resizing' panel in Export, that will also have drastic effects on the exported file size.
Not sure about this. Settings showing in Image sizing are:
Resize to fit (checked)
W 1''' H 1''' pixels
Resolution 24' pixels per inch
4) Export Quality. This trades off image detail preservation against file size. Does the above answer that one?

One recurring issue i have had has been that of printing, and am starting to wonder whether printing from edits might be part of that issue.

Hope this helps you help me! :roll:

 

[Evan]

Resize to fit being checked with your settings means that you are downsizing all your pictures to be 1'''x1'''. Significantly smaller that a high quality jpeg off you camera. You should uncheck that box if you want to save full size edits.

Also, you should check the quality setting under image sizing.

 

[Brad Snyder]

Brad

Thanks as ever for a prompt reply.

Looking again, I am seeing a variety of file sizes in the original jpgs (shot using sRGB, )
The Canon is set to large jpg. There are files that are in excess of 5 MB, but these are the original files.
My way of doing things, and I accept that there are probably much better routes, but one gets into particular ways, is, once I have edited the images, often for the work website, to export them to an edits folder. This means that I can upload them more quickly. (The website has the facilty to reduce files to web friendly sizes so I don't do that.) <==== actually, you are, whether you mean to or not. See other red arrow
Looking in that folder I am now seeing the 5''-6''KB files sizes I mentioned.

To clarify the issues you raise:
1) Cropping. Often cropped, but I do try to reduce crops to minimum

2) Noise reduction. Rarely use

3) Downsampling. If you've made setting changes in the 'File Resizing' panel in Export, that will also have drastic effects on the exported file size.
Not sure about this. Settings showing in Image sizing are:
Resize to fit (checked)
W 1''' H 1''' pixels <===== this is the one.
Resolution 24' pixels per inch
4) Export Quality. This trades off image detail preservation against file size. Does the above answer that one? <=== this is a 1-1'' numeric setting in the Lr export dialog

One recurring issue i have had has been that of printing, and am starting to wonder whether printing from edits might be part of that issue.

Hope this helps you help me! :roll:

That little red arrow setting right there is throwing away about 9'% of your pixels. If I'm not mistaken, the 4'D is about 1'megapixels, native resolution. That would give you images of roughly 26'' x39'' pixels. In that resizing algorithm, you've chosen 1'''x1''', which is about a single megapixel. 9 megapixels are disappearing in that step. Which explains why the file sizes are so small.

Depending on your workflow needs, that's not necessarily a bad thing. If the end product is web-viewed images, you're fine. Lr is preserving all the original pixels if you should need them later.

 

[calaf]

Thanks to both replies. I am assuming that this is a default setting on Lightroom, as it is not one I recall changing.
(Regarding point 4, that is set to 1'', I remember one of the online video guides pointing me at that one!)

What do you think about the 24' pixel setting?

Another reason I felt that I was still using bigger files when uploading was the fact that the process seems to take an eternity, so I (rather naively now it seems) felt that this was the conversion that was taking the time!

And there was I thinking I was getting to know this program.

 

[dj_paige]

Uploading via most Internet Service Providers is slower than downloading.

24' pixels per inch is pretty much irrelevant (unless there is something unusual on the web site to which you upload).

 

[Conor Boyd]

What do you think about the 24' pixel setting?

If the images you're exporting are purely for website use, then the pixel setting is irrelevant.
The pixel setting is only relevant at the point at which the image will be printed on a printer.

 

[calaf]

So....if an export is not for a website, but is designed for a printer, what would the illuminae recommend?

I have long abandoned the idea of printing from Lightroom and print via Canon software, which, though not as versatile as the Lightroom module, gives me better results, and was one reason why I started exporting edits.

 

[Conor Boyd]

So....if an export is not for a website, but is designed for a printer, what would the illuminae recommend?

I think my LR exports are mostly (all?) set at 3''dpi. I don't remember explicitly setting it.
I've persisted with experimenting with LR printing until I got results with my Epson that I was happy with. I've got to the stage where the differences between LR & e.g. QImage are small enough (if any) that I stick with LR for the ease of use.

 

[Denis Pagé]

So....if an export is not for a website, but is designed for a printer, what would the illuminae recommend?

I have long abandoned the idea of printing from Lightroom and print via Canon software, which, though not as versatile as the Lightroom module, gives me better results, and was one reason why I started exporting edits.

In the Print module of Lightroom, choose "Print to JPEG". This way, you won't get those small 1''' pixels tall/wide images.