JPG file size: compression vs image size

[peter_azor]

<p>Hi folks,<br />let's say you have hundreds of thousands (and counting) of high-res files from PhaseOne IQ backs or Cruze scanners.<br />Uncompressed 16-bit .tiffs are elsewhere (with client), but you want to keep decent quality .jpgs on site (mainly for viewing on monitor, but some printing in publications is possible now and then).<br />Obviously, the compromise between image quality and file size is a concern.<br>

Would you:<br />1. keep the image size (approx 15000x10000px, some smaller, some bigger) and increase jpg compression (50%?), or<br />2. keep compression to let's say 80-90% and change the image size (to maybe 6000x4000px)?<br>

If one can achieve same file size going either way, which is better?<br />Thanks for every piece of advice, tip or opinion!<br>

Peter</p>

[Wouter Willemse]

<p>My choice would be option (2) because JPEG compression artifacts at high compression become very visible and not all of them are "undone" by seeing them smaller, for example severe banding, especially in shadow areas small details can easily become big blobs without any detail. If you use a size like 6000x4000 with 90%, you can still do fairly large prints in case of emergency. With a lot of pixels of dubious quality, I doubt you'd get equally good results.<br>

That said, I never tried. Hard disks are just too cheap (and I'm on much lower resolutions anyway). But if I'd have to, I'd probably go with the second options.</p>

[Ed_Ingold]

<p>JPEGs are fine for viewing or distribution once all the adjustments have been made to create a RAW or TIFF master. I reduce the pixel count to something reasonable for the client, like 12"x 8" @ 300 ppi (3600x2400 pixels). However I use the maximum quality (minimum compression) option for the JPEG copy to minimize compression artifacts in repetitive patterns. It makes no sense, and takes up a lot of bandwidth to send 200 MB files when 20 MB will do.</p>

[Jochen_S]

<p>I'd downsize at low compression too. - for viewing / bragging purpposes whatever fills a 5K iMac seems right. - What kind of thumbnails are you adding into publications? - Single column or centerfold makes a difference in pixel needs. I'd keep stuff big enough for worst case. Might something around 24MP be a perfect compromise? - It seems to be the current standard forn handling convenience.<br>

Personally I haven't downsized anything yet, since I shoot way smaller files and little enough to consider HDDs cheap.</p>

[Dieter Schaefer]

<p>Downsizing with no compression at all - is there really that much saving going to 80-90% that it's worth the risk?</p>

[kim_johnson1]

<p>In 2016 with storage so cheap, why is file size an issue. Get one, two or three 4TB (appx. $122) external drives and not worry about file size. <br /><br />http://www.amazon.com/Book-Desktop-External-Drive-WDBFJK0040HBK-NESN/dp/B00E3RH61W/ref=sr_1_5?ie=UTF8&qid=1459811076&sr=8-5&keywords=drive+4+tb<br /><br /><br /><br /> http://www.amazon.com/Seagate-Portable-External-Storage-STDR4000100/dp/B00ZTRXFBA/ref=sr_1_2?ie=UTF8&qid=1459811289&sr=8-2&keywords=drive+4+tb</p>

[john_wheeler6]

<p>Hi Peter<br>

I will take a slightly different approach since there is important information missing. You can scale from what I give appropriately.<br>

<br />15,000 x 10,000 pixel image at 16 bit depth TIFF no compression would be a 900 MB file and I will round up to 1G per image to make the calculations easy. If you have 500,000 files, that ends up being 500TB so I can understand not wanting to have that much storage.</p>

<p>I will assume that these images need no more editing or adjustments (if they do, then that is an issue with any further suggestions below)<br>

<br />I will assume to start all you need is a 8 1/2 x 11 print size at 300 dpi for prints and that resolution would also be good enough for you to view on a monitor. At 16 bit depth you would need 50MB per file for that quality. <br>

<br />Just that alone would bring your storage needs down to 25TB or about six 4TB drives. That would be simplest solution as some have already mentioned.</p>

<p>Tread lightly going for further JPEG and further compression as here can be real trade-offs you need to decide</p>

<p>I will assume these images are in ProPhoto RGB color space to capture the full color depth the cameras/scanners are capable then for your images then you need 16bits color depth anyways to avoid banding and you cannot have a 16 bit JPEG</p>

<p>If you are willing to render down to Adobe RGB or sRGB, and lose the color gamut then depending on what your printer needs for bit depth, you could go to 8 bit TIFF and get down to storage needs of 12.5 TB or about three 4TB drives. Note that you can get some banding using 8 bit depth with Adobe RGB color space yet it is not frequent. yet depending on how your print, there are some printers paper combinations that now have a color gamut outside Adobe RGB. So it depends on your needs.</p>

<p>Finally, if you are fine with 8 bit images (note some monitors are 10 bit so you cold again have some banding) and all above conditions mentioned, then going to JPEG at max quality compression would be the next step and would save considerable. JPEG compression at high quality compression hides the compression artifacts pretty well yet they they can raise their ugly head if you are going to do additional editing. This would most likely get you down to a single 4TB drive.</p>

<p>If you don't care about the occasional artifact showing up with no editing, going for a light JPEG compression could easily buy you another 2X in storage space.</p>

<p>If you need more focused recommendations, I think you would need to supply more information about if more edits will be done, required resolution, needed color space, and any HD constraints (e.g. total costs) to provide more targeted suggestions.</p>

<p>Hope this is some help.</p>

<p>Instead of your file size resolution you gave and 16 bit depth TIFF (no compression)</p>

[marc_rochkind]

<p>I'm with Kim. I would:</p>

<p>3. Estimate how much it would cost me to ignore this trade-off, observe that the number is very low, and just keep the JPEGs that I have. UNLESS, your time has no value, and you enjoy reconstituting JPEGS, more than, say, making photographs.</p>

[hapien]

<p>From high quality source material a jpeg compression that equals jpeg quality 80 can be done with almost no visible loss of image quality. For mainly for viewing on display images it it useful to know resolution of intended display. Imac 5K notion is good for aim high purposes. For 3:2 image ratio images long edge should then be around 4320 pixels. It is possible to make quality prints from such file.</p>

<p>If time is short for resampling operations and images are still keepers, just buy more external hard drives.</p>

 

[sebastianmoran]

<p>How big a file to keep depends on the possible use. You start with big files, so you obviously have some uses for these. I would keep jpg's at 80+ quality and discard the raws and tiffs.</p>

<p>The biggest payoff for me is rigorous culling, rather than the choice of how to store the selected images. That is, deleting completely all the additional shots, the near duplicates, the ones that weren't quite as good. So tempting to save some of these, but realistically I'll never go back to these almost good shots.</p>

[doug_armstrong]

<p>John Wheeler nailed the technical question. Sebastian nailed to business question.</p>