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Image quality lost through editing with Photoshop?

Mar 9, 2012 5:33 AM

Tags: #photoshop

I find a number of professionals using Lightroom as their primary photo editor. 

 

I did a search on Lightroom vs Photoshop.  I found the following listed as the first reason for choosing Lightroom: 1.  Nondestructive Editing.  Nothing is actually changed (by Lightroom) in an image until it is exported.  This means you can make an adjustment, change it again and again, but no quality is lost as it would be with Photoshp.  This is reported in Outdoor Photographer.

 

My impression is there is no lost of image quality in Photoshop if you are working on a layer copy of the Background.  Photoshop tries to prevent degradation of the original image by requiring it be copied  or otherwise freed before the background can be changed.

 

Image quality can be lost in downstream layers through processes such as changing image size. 

 

Is my statement correct about loss of image quality and the 'analyst' from Outdoor Photographer misstating things?

 
Replies
  • Noel Carboni
    23,534 posts
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    Mar 9, 2012 5:50 AM   in reply to vince heying

    There's far too much hype and worry about "destructive" editing in the world, in my opinion.

     

    When everything was done in 8 bits/channel, it was possible to begin to see editing degradation accumulate in images fairly quickly, especially if gentle gradients or strong adjustments were used. 

     

    But 16 bits/channel data has changed all that.  Practically speaking, you can adjust pixel values all day, and even do radical adjustments, in 16 bits/channel and not begin to see a problem visually.  There's just enough extra precision in the format that the integer round-off errors don't accumulate into anything meaningful.

     

    Once you open a raw file into Photoshop, the Camera Raw converter "bakes" the settings you choose into pixels - which if you're concerned about quality should be 16 bits/channel.  For almost all cameras today, and if you don't exceed the color space gamut during conversion, 16 bits/channel provides more image quality than the camera can deliver. 

     

    Most folks feel that doing the big, radical adjustments (such as color balance, changing exposure on a poorly exposed image, or lightening shadows through the Fill Lighting control) should be done in Camera Raw.  Then, after the image is open, you can choose to edit pixel values or use Adjustment Layers, which give you the option of changing them repeatedly - just like what you're talking about in Lightroom.   But even this is not practically necessary.

     

    Unfortunately I see a lot of people, because of fear of the word "destruction" going hog wild using layers, which can complicate and slow their editing experience - when instead a few simple pixel-based edits would get the job done nicely.

     

    My advice:  Be mindful of formats and of accumulating error, but don't take an extreme approach.  If you can do a raw conversion to 16 bits/channel pixel data, then do a few simple edits to get the photo the rest of the way prepped for its use, just do it.  As with everything, moderation!

     

    -Noel

     
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  • Currently Being Moderated
    Mar 9, 2012 5:55 AM   in reply to vince heying
    Nondestructive Editing.  Nothing is actually changed (by Lightroom) in an image until it is exported.  This means you can make an adjustment, change it again and again, but no quality is lost as it would be with Photoshp.

     

    The statement is not (completely) incorrect but not terribly relevant, in my opinion, because

    • one can do the same with Adobe Camera Raw and store the raw-data as a Smart Object in a psd, tif or psb

    • by adhering to practices of non-destructive editing (using Adjustment Layers instead of Adjustments, Layer Masks instead of erasing, applying Filters and transformations on Smart Filters) the original data can also be maintained

    • certain techniques (for montages, retouching etc.) are just not available in Lightroom

    But one could inadvertently damage an image in Photoshop in ways that Lightroom just does not offer.

     

    My impression is there is no lost of image quality in Photoshop if you are working on a layer copy of the Background. 

    When converting raw-data to 8- or 16-bit-images information originally available in the one-12-(or higher-)bits-channel raw-image can be lost and some corrections may be much harder on the processed data than on the raw-image, I guess.

     

    And as Noel said: Working in 16-bit can help minimize deterioration for Adjustments that might be desastrous in 8-bit.

     
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  • Noel Carboni
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    Dec 23, 2006
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    Mar 9, 2012 6:03 AM   in reply to c.pfaffenbichler

    Hm, I wonder what the bit depth of Lightroom's internal processing is...  Not being a Lightroom user I don't know, but being a computer geek I can tell you that there IS some data format Adobe has chosen to use, and I doubt very much that it's high precision floating point because that would slow things down terribly.

     

    I know that with my own plug-in software I use a 32 bit integer format internally, which provides even more accuracy for internal operation than 16 bits.  Perhaps Lightroom does as well.

     

    -Noel

     
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    Mar 9, 2012 6:08 AM   in reply to Noel Carboni

    Swoosh … there it goes over my head …

    I have no idea about Lightroom’s processing but if I understand correctly Camera Raw performs the same, anyway.

     
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    Mar 9, 2012 7:53 AM   in reply to Noel Carboni

    IMO "non-destructive" is an unfortunate name for it. The issue isn't destruction or not (I agree with Noel re 16 bit precision) - it has much more to do with a flexible workflow. The main advantage is that you can go back and re-adjust multiple parameters as you go along, without having to do it all over again. Re-editable would be a much better name for it.

     

    Have you all seen the new Lightroom price BTW? They're giving it away for peanuts now. I think I'm buying, just for upgrade insurance.

     
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    Mar 9, 2012 9:14 AM   in reply to vince heying

    The distinction between LR and PS relate to how the programs process image data. They can both retain or wreck your image.

     

    PS actually edits pixels in a live working environment. If you convert from RGB to gray and then reduce the scale the image, you can't decide later to switch back to RGB (unless you have multiple backup copies of the image saved in history)

     

    LR takes notes about what you want to do to pixels and does not apply any changes to the file until you save/export. LR is more like a node based image editor than Photoshop is.

     

    Google for "node based image editing" to see what non-destructive image editing really means. 

     
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    Mar 9, 2012 9:34 AM   in reply to vince heying

    "Hi Vince.

     

    I've been using Lr since V1. In comparable versions, Lr & Ps will have the same RAW engine. Just the interface is different. The primary advantage of Lr over Ps is the catalog/database. Unless you don't already have Ps, then price is a factor. I think if you ask this question in the Lr forum, you will be avalanched by enthusiasts.

     

    The Lr catalog allows you to manage you images in a much more convenient and efficient manner than in Bridge. Bridge is a wobbley file browser. Lr is an image management Ferrari. For a Ford price. Lr and Ps work together like cookies and cream. To edit a Lr image in Ps, it's drop dead simple. Ctl+E opens a copy of the file in Ps. Make adjustments, save, and the new file appears beside the original raw file in the catalog. There's lots more, and it's good stuff. The print module is excellent.

     

    Most heavy Lr/Ps users state that they do further editing in Ps on about 5% of their images. This would of course be the same using Ps Raw.

     

    The "non-destructive" factor may be oversold, but the catalog is the bomb.

     

    FWIW.

     

    Peace,

    Lee

     

    PS: "Non-destructive" is really not the proper term. It is "parametric" editing.

     
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  • Noel Carboni
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    Dec 23, 2006
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    Mar 9, 2012 9:35 AM   in reply to arc fixer

    I've always wondered...  Is Lightroom's catalog and proprietary database image storage as reliable as the computer's file system itself?  Do people see it "bomb" out and lose their data?

     

    -Noel

     
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    Mar 9, 2012 10:23 AM   in reply to Noel Carboni

    Hi.

     

    Is Lightroom's catalog and proprietary database image storage as reliable as the computer's file system itself?

     

    When I first got Lr, I haunted the Lr forums. I remember that some users reported losing their catalogs, but it was usually narrowed down to user error, and the catalog was recovered. Usually the problem involved external hard drives and backup systems. I'm not qualified to comment as to the stability of Lr relative to the OS in theoretical terms, but I have over 20,000 images in my catalog and it's been solid as a rock, and still fast. Power users have reported running catalogs of well over 100,000 images without a hitch.

     

    Lee

     
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  • Noel Carboni
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    Mar 9, 2012 10:31 AM   in reply to vince heying

    vince heying wrote:

     

     

    I have never before seens a comment that extensive work on an image in PS would deteriorate the quality of the image.

     

     

    Well, think about it - 8 bit numbers being processed through algorithms are going to lose at least half a bit of precision on average each time, and depending on the operation possibly more.

     

    Half a bit out of 8 is pretty big.  Half a bit out of 16 is a lot less (you find it's really 15 when you get to know Photoshop).

     

    -Noel

     
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    Mar 9, 2012 11:13 AM   in reply to arc fixer

    I know this is veering OT but since LR4 is out and 150 bux I was thing of diving in - mainly for it's raw and DAM features (starting on family photo archive, a family of professional photographers!). Can LR catalogs be "published", like to the web or do I need to look @ open source like Razuna or the like?

     
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    Mar 9, 2012 12:06 PM   in reply to vince heying

    Hi Vince.

     

    I am just learning my way around Photoshp.  I have spent 18 months learning how to start and to stop it.

     

    Good point. But if we peg the learning curve of Ps at 10, Lr comes in around 2 or 3. Like learning to drive a car as opposed to learning to fly a jet.

     

    Smart Objects would make PS more re-editable.

     

    True, but still no match for Lr or Ps RAW.

     

    I have never before seens a comment that extensive work on an image in PS would deteriorate the quality of the image.

     

    Extensive work will do what the user asks it to do. In the first 18 months I had Ps, I asked it to do lots of things that I now realize deteriorated my images. Forever.

     

    Regarding LR, I have created for me a workflow that requires PS.

     

    So did everyone before Lr came out. And yet, Ps users by the thousands, if not millions, have adopted Lr. Many if not most with a greater time investment in Ps than 18 months. I dropped my Ps centric flo the moment I realized what Lr could do. I had been using Ps pretty heavily for about 5 years by that time.

     

    I feel LR works best for experienced photographers who are shoooting a lot of pictures.

     

    While it's true that experienced photographers might realize more benifit, maybe not. It works great for everyone.

     

    That person has good images, images that need little editing, to start the output process.

     

    This is not true in the sense that the majority of Lr users are mediocre photographers at best. For the simple fact that most photographers (even "pros") are mediocre at best. And Lr was conceived with these folks in mind. It has the true "pro" stuff, but in an amateur friendly environment. Judging by the images and questions posted on photo and Lr forums, there are many, many, low level photographers using it.

     

     

    I am an inexperienced photographer shooting just a few pictures.  So I put a lot of effort into getting a good print from my mediocre shots.

     

    You obviously care about your images. Care more when you are shooting them. This is boiler plate advice. Time spent mastering your camera will pay off better dividends than learning to fix bad photos. This was true before the digital age, and it's just as true now. Ultimately, no matter how hard you massage it in Ps, Lr, or any other app, the quality of your final image will be a function of the quality of the original pixels you captured with you camera.

     

    So far as masks and all the rest, Lr has an Local Area Adjustment Brush which does just that. You paint the mask, complete with any number or combination of adjustments, with a brush. The mask and the adjustments to it can be easily changed later. A good spot removal tool. A great red eye tool.

     

    File size isn't a huge factor these days, but it still counts. Instead of layers and the pixel data for each of them as in Ps, Lr has the pixel data once, and a sidecar file with the adjustments settings in a much smaller file. Not a big deal for storage, but when rendering, maybe a bigger deal. Lr also pre-renders previews at various sizes (you can program this, plus how long it keeps them). I could go on and on (and I have).

     

    Bottom line, it's a great tool for anyone who takes photos. For the price, it's a no brainer for $150. If you have the $150. Not true for many of us these days.

     

    Anyway, Vince,  I hope you don't think I'm picking on you. I answered you in detail because you made such good points. And the answers might be of general interest.

     

    Peace,

    Lee

     
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    Mar 9, 2012 12:26 PM   in reply to TLL...

    Hi.

     

    Can LR catalogs be "published", like to the web

     

    Yes. That became available in Lr3. You may need a plug in depending on the site, but Lr is plug in friendly and there are some great guys writing free/penny scripts for Lr. My host is Smug Mug, and I publish to it no problem. Lr4 may have onboard provisions for many of the top sites. Lr developers seem headed in that direction.

     

    At that price, I'd be doing a swan dive.

     

    Lee

     
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    Mar 10, 2012 10:08 AM   in reply to vince heying

    »I have never before seens a comment that extensive work on an image in PS would deteriorate the quality of the image.«

    I have seen several threads on banding – which can be the result of (extensive) Adjustments, especially easily when working in 8bit.

     
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    Mar 10, 2012 10:42 AM   in reply to vince heying

    vince heying wrote:


    To switch to LR I would need to redo my workflow from taking the shot to getting the output. 

    I've been checking out the trial extensively for the past two days. Yes, the workflow is clearly different in a lot of subtle ways, adding up to a significant mental readjustment. Still, shaking out old habits can be very healthy. All in all, I think I can work with this.

     

    My biggest previous problem with Lr was the library/catalog concept. I have everything tightly organized on the drives, and adding a second level of organizing would just be utterly confusing. But I discovered that you can bypass all that by importing everything into the same catalog and simply collapse the catalog panel for good. Then you use the folders panel to navigate the HDs as usual.

     

    I feel LR works best for experienced photographers who are shoooting a lot of pictures.  That person has good images, images that need little editing, to start the output process.

    Lightroom has always been recommended for high-volume work, but I don't really see that it's any better for that than a Bridge/ACR/Ps workflow. What Lightroom does, however, is to change the emphasis. The Lightroom emphasis is on photography, not post-production. Lightroom encourages you to improve your photographic skills, and for that it's a great tool. Photoshop, on the other hand, seems to say, "never mind that the shot is awful. We can fix that".

     

    So what's the verdict? I paid, and don't think I will regret it. This can be interesting.

     
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    Mar 10, 2012 11:02 AM   in reply to Noel Carboni

    Noel Carboni wrote:

     

    I've always wondered...  Is Lightroom's catalog and proprietary database image storage as reliable as the computer's file system itself?  Do people see it "bomb" out and lose their data?

     

    -Noel

    The images themselves are stored on the computer's file system, so in my mind their safety depends on the file system's reliability.  I don't know how often or why a LR catalog should get corrupted, but discipline in making backups is essential.  Lightroom conveniently lets you back up the original photos when you catalog them and you can opt to backup the catalog itself every day or every time you open LR.  This should be done on an external drive, of course, and many people will want to have more than one backup.   LR doesn't automatically back up images that were exported or post-edited in Photoshop, so it is important to do that yourself.´

     
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    Mar 10, 2012 11:20 AM   in reply to vince heying

    Oh, one more thing (and that applies to ACR 7 as well when it arrives in CS6):

     

    Highlight recovery actually works, without just depressing everything as it does now. I used to layer two ACR smart objects with a luminosity mask (and sometimes even groups and nested groups each with a separate mask), just to tackle highlight recovery. No longer necessary. The new slider layout makes wonderful sense and works infinitely better.

     
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    Mar 11, 2012 12:43 AM   in reply to Marian Driscoll

    If you convert from RGB to gray and then reduce the scale the image, you can't decide later to switch back to RGB (unless you have multiple backup copies of the image saved in history)

    One could if one used Smart Objects to store the full resolution color content.

     

    Edit: Marian, naturally I don’t doubt that you are aware of that and one could of course argue that the Smart Object’s content is a file of its own.

     
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    Mar 11, 2012 7:50 AM   in reply to c.pfaffenbichler

    Smart Objects, layer effects/styles, and the history panel are all attempts by Photoshop to come close to node based image editing but the core of the program is still based on live editing of pixels. Changing the way Photoshop works in this regard would be such an upset that it would alienate the userbase. I suspect a totally new app, Lightroom, was the best way to introduce this kind of image editing.

     

    Node based image editors are prevalent in video/film/animation production where one needs to affect multiple images (frames) en masse. There are some nifty image editors in that field.

     
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    Mar 11, 2012 9:28 AM   in reply to Marian Driscoll

    Marian Driscoll wrote:

     

    Changing the way Photoshop works in this regard would be such an upset that it would alienate the userbase. I suspect a totally new app, Lightroom, was the best way to introduce this kind of image editing.

    Not to mention the massive rewrite.

     

    Give Lightroom layers and masks, and we're almost there, a complete photographer's toolbox. Then rename Photoshop and target prepress, retouchers, web designers...

     
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