Question about raw files after editing

Started Nov 16, 2011 | Discussions
Coribu
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Question about raw files after editing
Nov 16, 2011

To all you pro's out there...

I need some understanding about raw files. I was wondering after you take raw photos...I know you edit them in say..Photoshop. So after you are finished editing them, do you just save them to jpeg? I would think that that would defeat the purpose of using raw to take the photos? So is there some software that I need to save raw images? Sorry for the silly questions...it's ok to laugh @ me.

Thanks!

Chris R-UK
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Re: Question about raw files after editing
In reply to Coribu, Nov 16, 2011

Generally you would save them as a JPEG after you have finished with the raw processing, but you might save them in another format, e.g. TIFF or even Photoshop PSD if you were going to do further processing. You can't do anything useful with a raw file, e.g. print it, e-mail it, post it to the web, until you have converted it to a format that other programs recognise.

Some programs, particularly Lightroom and Aperture (Mac only) save the edits in a separate file. You only need to produce a JPEG if you want to do something specific with the image, e.g. e-mail it. You can also print directly from these programs without producing a permanent intermediate file. You can go back and change your edits at any time or even produce a second version, e.g. in B&W.
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Wally626
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Re: Question about raw files after editing
In reply to Coribu, Nov 16, 2011

Programs like Aperture and Lightroom preserve the RAW files in their libraries. If you use something else just store the original RAW files on your hard drive. Open the file in say Photoshop and save it as a copy in the PSD format until you are done with it then export to JPEG. You could keep the PSD file around as well. This can get complicated having RAW, PSD and JPEG versions of files, but not undoable. Of course this is also the strong selling point of Aperture and Lightroom in that you do not have to keep track of multiple versions.

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Coribu
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Re: Question about raw files after editing
In reply to Chris R-UK, Nov 16, 2011

Oh ok...that helps me a lot! So...if I save a raw photo to jpeg after processing than it's not going to compress it and ruin all the work I've just done? Sorry...not a computer person lol. And when it's opened on a website or something it will still be the same picture I edited? Or a compressed jpeg version? Thanks

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Coribu
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Re: Question about raw files after editing (to Wally)
In reply to Wally626, Nov 16, 2011

Thanks for getting back to me

So really the point of exporting in jpeg is for emailing, web postings and stuff like that? When I export in jpeg does the raw file I edited get compressed and therefor undo/ruin all/most of the work I just did?

Thanks again

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pixelless
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Re: Question about raw files after editing (to Wally)
In reply to Coribu, Nov 16, 2011

I´m no pro by any mean of the word! lol....

But I save my photos on the original RAW (NEF) format. I only convert them to jpeg if I need to post them on the web, or e-mail to someone.

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Wally626
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Re: Question about raw files after editing
In reply to Coribu, Nov 16, 2011

When you open the RAW file in Photoshop and save it. It will save as a PSD file and leave the RAW file alone. Leave it as a PSD file until you are ready to export the final version to JPEG. The PSD file is not lossy compressed so will not suffer the same way as multiple edits on a JPEG file. If you think you might do more edits retain the PSD version. The only drawback is if you decide you want to go back to an intermediate stag of editing you may have to start over from the RAW file. In Aperture or Lightroom you just have to change the adjustments back to what they were.

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Chris R-UK
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Re: Question about raw files after editing
In reply to Coribu, Nov 16, 2011

The effects of JPEG compression only become significant if you save them at very high compression ratios to keep the file size down for e-mailing, or if keep on saving, reloading and saving again multiple times.

Probably 99% of all images taken by digital cameras are JPEGs. Have you heard a great outcry about loss of quality from using JPEGs? Probably not!

Stop worrying. JPEGs are fine especially if you save them at the lowest compression ratio, highest quality level. It will still be the same image that you edited.
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Coribu
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Re: Question about raw files after editing
In reply to Wally626, Nov 16, 2011

Thanks so much for clearing that up for me! I'm sure I'll have to read over it again before I really get it lol..but thanks for the advice.

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sterretje
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Re: Question about raw files after editing
In reply to Coribu, Nov 16, 2011

Coribu wrote:

Oh ok...that helps me a lot! So...if I save a raw photo to jpeg after processing than it's not going to compress it and ruin all the work I've just done? Sorry...not a computer person lol. And when it's opened on a website or something it will still be the same picture I edited? Or a compressed jpeg version? Thanks

Your jpegs will always be compressed and always with loss of quality; how much loss is configurable . If you can see the difference between RAW converted to a high quality jpeg and the RAW converted to a lossless format is debatable. But if you open and save a jpeg a couple of hundreds or thousands of times the difference might become visible.

So what people do when they process the RAW. Every time they stop working on the RAW file or have finished one or more steps of the post processing, they save it in a format without loss (e.g. the native format of the program they use). When they continue working, they open the saved file (not the RAW file) till they are happy with the result which they also save in the lossless format.. When they e.g. publish on the web, they convert the lossless file to jpeg (while keeping their final lossless file).

Some programs keep a so-called sidecar file for each raw file that you have opened in the program; it contains all the edits that you have done on the RAW file. So you can save as jpeg (or whatever format you prefer) or not save at all but each time you open the raw file, the sidecar file is read and the edits are applied and you can continue working where you were till you're happy with the result.

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Leonard Migliore
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Nothing alters the RAW file
In reply to Coribu, Nov 17, 2011

Coribu wrote:

Thanks for getting back to me

So really the point of exporting in jpeg is for emailing, web postings and stuff like that? When I export in jpeg does the raw file I edited get compressed and therefor undo/ruin all/most of the work I just did?

I use Lightroom, but I believe that other RAW editors work the same way:

When you "edit" a RAW file, you're not actually doing anything to it. You're just generating instructions about how to interpret it. These instructions go in a separate "sidecar" file that's associated with the image file. So when you export a jpeg, you're just running the set of instructions for your RAW file to generate the jpeg file.

The RAW file itself is never changed. You can go back and make a new set of instructions (say, you want to print in black and white) but the RAW file still has all the original information just as it was taken.
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sacundim
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Editing and display use different formats.
In reply to Coribu, Nov 17, 2011

Coribu wrote:

I need some understanding about raw files. I was wondering after you take raw photos...I know you edit them in say..Photoshop. So after you are finished editing them, do you just save them to jpeg? I would think that that would defeat the purpose of using raw to take the photos? So is there some software that I need to save raw images? Sorry for the silly questions...it's ok to laugh @ me.

Editing photos and displaying them are two different tasks with different requirements. JPEG is a perfect format for displaying photos to an end user—it gives high image quality in a small file size.

However, JPEG is bad for photo editing work. Reasons:

  • Editing involves changing image levels, which can lead to posterization. To avoid posterization, you need to have more than 8 bits of data per pixel color channel. JPEG only supports 8 bit files; RAW and TIFF support more.

  • JPEG uses lossy data compression to give high quality in small file sizes. A consequence of that, however, is that if you repeatedly open a JPEG, edit it, and save it back as a JPEG, you get some really ugly compression artifacts. This is of course very bad, and for that reason, JPEG is unsuitable for image editing.

A good analogy to use here is that RAW workflow is using the RAW file as a "negative," and JPEGs as the final "prints." The photos you give to people are prints (i.e., JPEGs), but you keep the negatives (the RAWs) in case you want to make a different version of the same photo (e.g., you want to make an enlargement).

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Guidenet
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My workflow
In reply to Coribu, Nov 17, 2011

Here's my workflow. I choose a RAW file. Remember, a RAW file is not an image and your can't see it. It's just the Raw recording off the sensor... red, green and blue dots. When you look at one, you're looking at a little embedded Jpeg there for you to see. It may or may not represent what the RAW file looks like if it were rendered.

Anyway, you load the RAW file into a RAW converter and editor. Photoshop or Lightroom are not really RAW converters. Adobe uses Adobe Camera RAW or ACR to render the RAW file. ACR is integrated in Lightroom but not Photoshop or Elements. It's separate. If I double click on a RAW file, ACR opens if that's what I'm using as my default RAW editor. I make my edits then ask it to open in Photoshop. ACR goes away and my RGB rendered image appears in Photoshop. My nice 14 bit RAW file was edited in a nice 16 bit workspace with all the detail still there.

When I open it in Photoshop it is a 16 bit RGB image type. I do some final tweaks and save it as a TIFF file type because a TIFF is 16 bit and nothing is lost. We call it non-lossy. I name my RAW file and associated TIFF the same name and add the date to the file name. Something like gold_dog-11-16-11.NEF, gold_dog-11-16-11.TIF, and gold_dog-11-16-11.jpg. This way if later I want to track down the RAW from a Jpeg, I can just look for the name and date. The non-Keeper RAWs I leave with the weird name the camera gave it.

When I'm done saving the TIFF and nameing the untouched RAW the same thing, I now size it for email, web or printing and change it to a lossy 8 bitr JPeg. I do not work on it when it's an 8 bit Jpeg. The Jpeg has the same name.

Now I have a RAW, edited 16 bit non-lossy TIFF and a Jpeg for use and they share the same name other than the last file name extensions. The reason I don't alter the RAW file is that I may want to render it with a different RAW editor later or maybe I deside to do it differently. The reason I keep the edited TIFF is that I can create a small JPeg for email and a larger one for printing or just print the TIFF. I might want a 4x5 for the web and a 16x20 for the wall. I use that TIFF with all the detail intact to create those 8 bit lossy Jpegs. JPeg is not a good way to archive in that 95% of the data has been tossed away. They also compress the data everytime you make some change and resave it. I might end up with one RAW, one TIFF and several JPegs in various sizes, all with the same name except the Jpegs might get additional info in the name like gold_dog_web-11-16-11.JPG being a JPeg for the web.

Get it? You see I can look at that name and tell exactly where it came from and why I made that Jpeg. I hope this all made sense.
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AnandaSim
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Actually....
In reply to Leonard Migliore, Nov 17, 2011

I'm not sure whether I wrote about this before but there were these two guys at Open Talk who were adamant about Nikon .NEF and ViewNX....

The clarified that ViewNX software does indeed change the metadata and the embedded JPEG. The original RAW data is not changed but effectively, if you tweak the image in ViewNX, the metadata is changed and the embedded JPEG is changed.

This is quite unlike how Lightroom works where the whole RAW file is untouched.

Leonard Migliore wrote:

I use Lightroom, but I believe that other RAW editors work the same way:

When you "edit" a RAW file, you're not actually doing anything to it. You're just generating instructions about how to interpret it. These instructions go in a separate "sidecar" file that's associated with the image file. So when you export a jpeg, you're just running the set of instructions for your RAW file to generate the jpeg file.

The RAW file itself is never changed. You can go back and make a new set of instructions (say, you want to print in black and white) but the RAW file still has all the original information just as it was taken.

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Guidenet
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Re: Actually....
In reply to AnandaSim, Nov 17, 2011

AnandaSim wrote:

I'm not sure whether I wrote about this before but there were these two guys at Open Talk who were adamant about Nikon .NEF and ViewNX....

The clarified that ViewNX software does indeed change the metadata and the embedded JPEG. The original RAW data is not changed but effectively, if you tweak the image in ViewNX, the metadata is changed and the embedded JPEG is changed.

This is quite unlike how Lightroom works where the whole RAW file is untouched.

Leonard Migliore wrote:

I use Lightroom, but I believe that other RAW editors work the same way:

When you "edit" a RAW file, you're not actually doing anything to it. You're just generating instructions about how to interpret it. These instructions go in a separate "sidecar" file that's associated with the image file. So when you export a jpeg, you're just running the set of instructions for your RAW file to generate the jpeg file.

Ananda, that's really what Leonard said. That metadata you're talking about is the instructions he's talking about. It's just the startup settings for what the embedded Jpeg should look like and has nothing to do with the RAW data. It has nothing to do with what the eventual rendered RGB image will look lke nor anything to do with the editing of the RAW data. I've set my RAW converter to basically ignore that data at startup, as if all camera settings were set to zero.

That metadata has to change as you edit a RAW or you'd not see what you're doing in the embedded Jpeg.

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