# reduce file size



## alaios (Apr 14, 2016)

Hi all,
once I do the basic lightroom edits I pass photos to photoshop for some more skin smoothing. I would like to hear your tips to reduce the file sizes produced from photoshop, which tend to be huge (editing raw files).

Regards
Alex


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## Johan Elzenga (Apr 14, 2016)

If you don't want to reduce the image size in pixels, there isn't much you can do. Raw files have only one color channel per pixel, RGB files have three color channels. That is why a TIFF file will be larger than the corresponding raw file, even if you use 8 bits per color and LZW-compression. If you save your images as 16 bits per color, the file size is really huge and LZW-compression doesn't work. So you could consider reducing them to 8 bits per color. As long as you don't plan to make further edits, you won't see the difference in most cases. Or you could learn to use Lightroom for all your edits (skin smoothening is possible in Lightroom too), so you don't have to save so many TIFF duplicates to begin with...


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## alaios (Apr 14, 2016)

I think my tiff files end up 350mb!!! Is this true to you too?


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## Johan Elzenga (Apr 14, 2016)

alaios said:


> I think my tiff files end up 350mb!!! Is this true to you too?



That is probably because you use layers. A 16 bits/color file with a few layers will indeed grow to huge proportions.


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## alaios (Apr 16, 2016)

so what to do before saving those?


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## Johan Elzenga (Apr 16, 2016)

If you don't need them anymore, you could flatten the file. But that would defy the use of layers in the first place. Or just accept that layers make the file size big. Buy a bigger disk if you have to...


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## Linwood Ferguson (Apr 17, 2016)

And this is why a non-destructive editor is a real benefit to someone who does a lot of photos.  I couldn't afford the disk space if I had to use photoshop on all images.


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## Johan Elzenga (Apr 17, 2016)

Yeah, although I wonder why people worry about disk space and file sizes at all. Disk space hardly costs anything anymore these days. You can buy a 4 TB external disk for a less than $ 150.-.


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## clee01l (Apr 17, 2016)

JohanElzenga said:


> Yeah, although I wonder why people worry about disk space and file sizes at all. Disk space hardly costs anything anymore these days. You can buy a 4 TB external disk for a less than $ 150.-.


Disk space is not the only concern for a 350MB TIFF file. Files of that size require tremendous amounts of resources(RAM CPU).  I would not want to attempt to process that file on a minimally spec'ed computer.


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## Johan Elzenga (Apr 17, 2016)

clee01l said:


> Disk space is not the only concern for a 350MB TIFF file. Files of that size require tremendous amounts of resources(RAM CPU).  I would not want to attempt to process that file on a minimally spec'ed computer.



No, of course not. But the OP already has files that size, so apparently his computer isn't that minimally spec'ed.


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## Linwood Ferguson (Apr 17, 2016)

JohanElzenga said:


> Yeah, although I wonder why people worry about disk space and file sizes at all. Disk space hardly costs anything anymore these days. You can buy a 4 TB external disk for a less than $ 150.-.



My files average about 25MB   If I bulked them all up to 250 MB by converting to TIF, I'd go from about 1.5TB to 15TB.  I back up to the cloud (S3) where I now pay about $10/mo for storage.  This would increase my backup time 10 fold, and increase my cost 10 fold as well.  Now maybe I get around that by finding something unlimited (e.g. Amazon Cloud Drive), but the time is still an issue, even more so as the unlimited ones tend to be speed limited in various ways.

It's not just about the disk space on your system.  

And I use raid disks on the computer.  Going to 30TB of disk inside the computer might be difficult, at least at a reasonable speed, so I might need an external raid system, yet more cost.  Especially to maintain the same speed per megabyte, and almost impossible to maintain the same speed per image of read/save/browse.

I try not to worry about space unnecessarily, so I do not hesitate to edit individual shots in photoshop, but I have hesitated about converting to some other system for possibly better conversion or noise control as a general course, as there's much more cost to it than just a couple more disks.


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## Johan Elzenga (Apr 17, 2016)

Ferguson said:


> My files average about 25MB   If I bulked them all up to 250 MB by converting to TIF, I'd go from about 1.5TB to 15TB.



But why would you do that? If you feel that you need Photoshop for almost every image, then what you really need is to learn how to better use Lightroom...


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## alaios (Apr 17, 2016)

I use photoshop for portraiture plugin


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## Linwood Ferguson (Apr 17, 2016)

JohanElzenga said:


> But why would you do that? If you feel that you need Photoshop for almost every image, then what you really need is to learn how to better use Lightroom...



*I* wouldn't, but this conversation started with a pass through photoshop being part of routine workflow, and me saying that's why non-destructive editors are nice.  And there are many people who don't use LR or any non-destructive editor.


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## Johan Elzenga (Apr 17, 2016)

alaios said:


> I use photoshop for portraiture plugin



In that case you may consider sending the files to Photoshop as 8 bits AdobeRGB, rather than the default 16 bits ProPhotoRGB. And you may consider to flatten the file when you're done with it. It looks like that plugin creates layers, but I doubt that keeping those layers is very useful in this particular case.


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## alaios (Apr 17, 2016)

JohanElzenga said:


> In that case you may consider sending the files to Photoshop as 8 bits AdobeRGB, rather than the default 16 bits ProPhotoRGB. And you may consider to flatten the file when you're done with it. It looks like that plugin creates layers, but I doubt that keeping those layers is very useful in this particular case.



how much I loose with the 8bits adobe rgb?


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## Linwood Ferguson (Apr 17, 2016)

Just to go off on a slight tangent... I use Portrait Professional on the extremely few times I need portrait touchups.  one thing I have found (at least on the older version I have) is that you cannot pick up with the last edits -- once you save, you are done; to reproduce you have to go back and redo the edits.

If your portrait work is like that as well, there may be little purpose in saving as TIFF at all.  If you find you get to the final result and never (rarely) go back, just export as a JPG from the portrait tool, which is tiny.   TIFF is more useful if you plan to re-edit a shot.  And there's no need to save the TIFF that you feed out to the plugin (as opposed to out from the plugin) because you can reproduce that easily in LR.


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## Johan Elzenga (Apr 17, 2016)

alaios said:


> how much I loose with the 8bits adobe rgb?



Not much, if any. Skin tones are well within the sRGB gamut and so is the color of clothing normally.


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## Linwood Ferguson (Apr 17, 2016)

JohanElzenga said:


> Not much, if any. Skin tones are well within the sRGB gamut and so is the color of clothing normally.



Well, sRGB doesn't equate to 8 vs 16, you get those choices separately.  You could certainly use 8 bit Adobe RGB for example to pass out from LR to Photoshop.

The difference in 8 vs 16 bits has more to do with editing shift.  16 bits gives you 256 intermediate shades between each 8 bit shade (65536 total vs 256 total on each channel).   Imagine something like this:  Imagine a histogram, now imagine one edit you make expanding one part of the histogram to make it much larger, e.g. raising shadow detail.  in 8 bits there's 256 shades, so say you expanded 10 of those to cover what was 40 spots.  This now leaves, for want of a better term, gaps between each of these 10.   More importantly, the rest of the histogram is pressed tighter together to make space for it, and in doing that, you actually lose data because what was 3 tones may have to fit in the space of 2, and one is lost.

The expansion where 10 cover 40 spots can lead to banding, as there is inadequate shades in between.  Many programs like Photoshop get around this somewhat by interpolating as it expands, so banding becomes less likely.

But there is no real way to make up for the ones that were lost.  If you then make another edit which expands those, photoshop may interpolate those but... it is making up the data, it may not be the real shades that were there.

Photoshop actually does a very nice job of this interpolation as you do successive editing, but repeated edit steps does degrade an 8 bit image slightly each time.  Whether it's enough to see or not depends on what the steps are and the image.   I think most of us choose 16 bits to be safe, not because we know it will make a difference.  It's the same way a lot of raw shooters choose 14 bit raw instead of 12 (if you have a choice) not because we know it matters in a particular case, but to be safe.

It's a shame there are not variable bit depths other than 8 and 16 for still editing; I suspect most editing would work just fine in (say) 10 bits, giving 4 times the tone shades, without going to 16 bits.

Color space is related indirectly to bit depth at best.  Wider gamuts like Pro Photo RGB can be represented in 8 bits, but there is more space between each tone as the overall gamut is somewhat larger.   But the decision to use 16 vs 8 is less about gamut really than providing the reserve tonal steps so that editing works.  After all, probably 99% of most images are going to be seen or printed at sRGB 8 bit.

Just to be clear - "using JPG repeated editing is bad" is about save/open with JPG, as it is mostly about storage space compression, which is a lossy compression.  It's not so much about 8 vs. 16.    8 vs 16 bit decisions are about editing STEPS in a destructive editor.  Steps in one session, like first raise exposure, then darken highlights, then raise shadows, then lower black point.  Each of these four steps cause parts of the histogram to be shifted, which in turn causes some data loss.  By having 16 bits you have plenty of data to loose and still have the result have all the tonal distinction of the original (say from a 12 or 14 bit raw).  By having 8 bits you start with less than the original, and then may loose some more in editing -- whether noticable or not depends on the subject and the editing steps and program.


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## Johan Elzenga (Apr 17, 2016)

It's not just about editing. The reason why 8 bits ProPhotoRGB is not a good idea is because ProPhotoRGB is such a wide color space, that two adjacent tones in 8 bits/color are visually different. That means that you can get problems with smooth gradients: you may get banding, even without making any further edits.


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