Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: louler on October 29, 2010, 01:56:11 pm
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Hi there, good to be here:)
I have been reading on this site and elsewhere about the difference between raw and jpegs.
Still I am not sure about the best way to edit a jpeg ( I am using an old cybershot sony 8.8mgb)
I always make sure the highest setting for quality is chosen , but I fear when I am editing the jpeg in photoshop , everytime I save the changes , the image just looses from it's quality right ? even if I chose maximum quality?
I would very much appreciate if you can explain what is the best way to edit jpegs without loosing quality should `i convert them to raw and edit in raw??
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I fear when I am editing the jpeg in photoshop , everytime I save the changes , the image just looses from it's quality right ? even if I chose maximum quality?
It depends on what you mean by “every time I save.”
Example 1: You open x.jpg in Photoshop, do some editing, save as y.jpg, then (while it's still open) do some more editing, and save as z.jpg.
Example 2: You open x.jpg in Photoshop, do some editing, save as y.jpg, then exit Photoshop. Later, you open y.jpg in Photoshop, do the same “more editing” as in example 1, and save as z.jpg.
The results in z.jpg from example 2 will (in principle, at least) be poorer quality than in example 1, because the second editing phase of example 2 started with the re-compressed JPEG.
So, if you think you might want to do more editing, it's best to save a .psd or TIFF file, as in:
Example 3: You open x.jpg in Photoshop, do some editing, save it as y.psd (or y.tif, as long as you don't choose JPEG compression for the TIFF), then exit Photoshop. Later, you open y.psd in Photoshop, do the same “more editing” as in example 1, and save as z.jpg. Your results would be the same as in example 1, since the intermediate .psd or .tif version saved all pixels.
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One quick piece of advice - if you are editing a JPG file, make a copy of the original file and work on the copy only.
What I have done in the past in this situation was to "save" the JPG as an 8-bit TIFF in sRGB color space. I make all the edits on this file, save it as a backup and then save a copy back to JPG. This minimizes any losses.
I'm sure there are other ways to do this, but this works for me.
Paul
ps: you can't save a JPG as a RAW file.
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Tks so much Gary that was very helpfull and easy:)
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Million tks Paul things are extra clear now:)
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If you are not using Lightroom or Camera Raw, you may want to consider “editing” JPEGs there using it as a parametric editor. There are some advantages to this approach (in LR, using virtual copies would provide even more). The original JPEG data would be left alone for one, but edits applied to the new iteration could be saved out as something other than a JPEG or just another JPEG.
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HI Digitaldog and tks !do you mean the camera raw from photoshop? or is there a software called camera raw?
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HI Digitaldog and tks !do you mean the camera raw from photoshop? or is there a software called camera raw?
Yes Adobe Camera Raw (ACR) in Photoshop.
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+1
+1
+1
BR
Erik
If you are not using Lightroom or Camera Raw, you may want to consider “editing” JPEGs there using it as a parametric editor. There are some advantages to this approach (in LR, using virtual copies would provide even more). The original JPEG data would be left alone for one, but edits applied to the new iteration could be saved out as something other than a JPEG or just another JPEG.
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tks Erick ! a lot! I'll do that :)
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Open the JPG and use Save As to save it as a PSD or TIFF file. You'll retain the original file "just in case" and you can save PSD and TIFF files as often as you like without loss of quality.
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What ever your workflow, back-up your original images first!
If your camera doesn't have a "raw" setting, you'll need to save as TIFF (more "universal" than psd). Once saved, append your file name such as this "file-name-wip" where "file-name" is the unique name you give the file instead of the generic file name set by your camera and "-wip" means Work In Progress. For info on this aspect, you can go to dpbestflow.org on file naming and metadata.
Once your files are renamed and backed up, be sure use adjustment layers to change your color, density, etc. on the file. Working on the file with tools such as burn/dodge, curves, levels, saturation, etc. directly on the image is permanent! When you are finished, save your "-wip" file and save it again as "file-name-master". Your master image can be the flattened version of your "-wip" file and can be resized and sharpened for output. When you do this step, make sure you rename the file once again with the print size, for instance.
Though you may have three or four files of your original, each will be a different version and each will have a different notation as to it's content: camera original (.jpg in your case), -wip: work in progress, -"-master", "-8x10": 8x10 flattened and sharpened file, etc.
Always work deliberately and with consistency. By working with layers, you never loose information unless the file is flattened (your ready-to-print files).
HTH,
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Dear Langler,
Many thanks for taking the time to explain :)
I like very much the wip tip ,I'll keep all the rest in mind ,my workflow will b much easier now tks to you.
So from what I understand, a jpeg won't loose any of it's quality as long as it is on a layer in photoshop right?
Best regards
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Good question. As suggested best to open you file and do basic adjustments with levels and save as a PSD file before continuing to work with it. Easy to see the damage for yourself by creating a simple action to open a file and resave it 20 times and observe the severe degradation that occurs. It surprised me the first time I saw the results.
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But you've got to save, close, reopen the jpeg file to see the image degradation to see the image deterioration. Simple re-saving the image 20 times from the same open file saves that same open file with twenty names!
At high quality, say jpeg quality 10-12, re-saving the image as a jpeg a few times it will be hard to see the damage. Drop the I.Q. to 4-5 and each re-save, close, reopen will start making the damage more obvious.
The big issue is to archive your original captures at the start, work on a copy of the image, save as a tiff or psd file and work with layers on your master image. Then if you need to send it via ftp, e-mail, etc., flatten the image, resize and then you can save a *copy* of the image as a high-quality jpeg file.