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Old Jan 10, 2003, 8:57 PM   #1
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Default copying digital pics...anybody know if this degrades them

I have a Sony digital camera and I transfer my pics from the camera media thru a memory stick/floppy adapter. Recently I have been copying my digital pics right from the adapter devise right to my CD burner. They seem to come out alright I just want to make sure that I'm not degrading the photos. Any ideas or comments
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Old Jan 10, 2003, 10:05 PM   #2
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If you do a straight copy using Windows Explorer or your CD burner appl. you should not have any degradation of the image data when you copy from the MS to your CD (or hard disk or any other media).

If your image file is in JPEG format (of type .jpg) and you open your image file using an image editing program and make even the slightest change, then if you do a <Save> command you will lose some image quality since JPEG is a lossy compression process. Each time you re-save in JPEG format some information is lost--the amount of quality degradation will depend on the picture content. The best workflow procedure to follow when you intend to edit the picture is to open your original (JPEG) image with your editor and immediately do a <Save As> command and specify a non lossy format such as TIFF. Then perform all subsequent editing on the TIFF file.
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Old Jan 10, 2003, 11:06 PM   #3
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jawz was right up to
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Originally Posted by jawz
... The best workflow procedure to follow when you intend to edit the picture is to open your original (JPEG) image with your editor and immediately do a <Save As> command and specify a non lossy format such as TIFF...
That gains you nothing - whatever damage was done by JPEG compression in the camera, saving it as a TIFF will not undo it. The only thing you will do is increase the file size and likely get rid of your EXIF data.

Save your images to CD exactly as they come from the camera - that is you "digital negative", don't mess with it. Once you have done that, you really don't have to worry to much about progressive loss with JPEG compression since you can always go back to the original. It isn't a bad idea to save intermediate work in a lossless format - the proprietory format that your photo editor uses is probably best since that will also save things like layers. Once you are through editing, JPEG is just fine to save the image since there will be no further saves.
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Old Jan 11, 2003, 12:39 AM   #4
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I beg to disagree somewhat with BillDrew's comment (or perhaps we are saying the same thing and it's just a semantic difference) that:

"...saving in TIFF gains you nothing - whatever damage was done by JPEG compression in the camera, saving it as a TIFF will not undo it. The only thing you will do is increase the file size and likely get rid of your EXIF data. "

Saving in TIFF of course will not undo any loss due to the camera's JPEG compression. That was not the intent of advocating saving a copy of the image file in TIFF format.

The point is that when you are beginning the process of modifying an image file, and before you intend to save the results of your modifications for the first time, save this modified image as a new file (different name) in TIFF format and leave your original JPEG file un-altered. Else, if one crops the image, say and then saves the file (as the default original .jpg) and then subsequently applies a filter and re-saves again as a .jpg at each save some information is lost. If however if the above steps were conducted with the image file first saved in TIFF (or in the image editor's proprietary lossless format) and all subsequent operations were performed on and saved as TIFF files then all of the image information that existed in the original file would still be preserved (except for the data lost through edits of course).

And as BillDrew pointed out, you can always go back to the original un-altered JPEG file for other edit/manipulation.
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Old Jan 11, 2003, 6:18 AM   #5
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I suppose you're both right, BillDrew is right to point out you always save a cam original - preferably lock the file afterwards. Jawz is right on the issue of of concatenating saves. This isn't so much of an issue for those who do less complex editing, since they just pull back a copy of the cam original with warts, rather than open up their edited copy.

On copying from memory stick to CD burn, I'd be careful if this was a 'move' i'e the files are deleted as transferred. CD burning is not infallible. Always make sure you delete off stick after you have opened up the folder on CD with a viewer and checked all the thumbnails are there and open OK. Occasionally, check your CD's can be read in other PC's., avoid 'packet mode' and use 'disc at once'.

However, and I do want to hear some sympathy! Why can't editing software produce an edit decision list married to the pic? the info's there in the undo list. That way you always copy the cam original and apply the last edit decisions before re-editing. It's worked that way in TV for years. No need to waste space on TIFFS then!
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Old Jan 11, 2003, 6:52 AM   #6
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I copy my files from the camera media to the hard drive. There is no quality loss. After I have edited the pic, I save the pic as another name. This prevents loss of quality on the original. I know that this takes up hard drive space but hard drives are cheap. I burn original and finished pics to cd and then delete them off the hard drive. I burn two copies of the cd. I keep one copy at my home and store the other at my daughter's home.
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Old Jan 11, 2003, 9:07 AM   #7
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jawz - I agree, we are trying to make pretty much the same point. When I first started dealing with a digicam, I did think saving as a TIFF instead of just copying the image as it came from the camera would be an advantage. As you noted, it isn't. Just trying to save another beginner from my early mistakes.

As voxmagna pointed out, unless you are doing very complex editing, it really doesn't matter very much which way you do it. And I agree with him about editing programs not doing something like saving the undo info (hisory pallet in PS) being one things that make going back to continue editing more difficult than it needs to be. That is why if I am going to be doing any complex editing in PhotoShop I use adjustment layers instead of simply adjusting (curves, saturation, ...) the image. Saving in PhotoShop's native format does save those. That isn't a good format for the final image since almost nothing else can read it.
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Old Jan 12, 2003, 5:47 AM   #8
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.....BillDrew, I don't use PS, but it's good to hear some opportunities for edit decision lists (EDL'S) applied. It surprises me that more image editors don't follow up on this.

Yes you're right there's no open data standard for the edit decision syntax or file format. But it seems strange that an opportunity to offer and build on a proprietary feature in their packages, hasn't been widely taken up yet.
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Old Jan 13, 2003, 4:41 PM   #9
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The losses in Jpeg are greatly over-rated. Yes it is lossy, but by how much?
The graduations in colour that are recorded are not visible to the eye, neither is your printer or monitor capable of showing them.
Photoshop reduces a 16 bit image to 8 bits before anything else happens and immediately you have lost far more information than JPG loses.
The first information lost in JPG is colour graduation and if you use a fine JPG compression you will be hard pressed to find the difference.
Try cropping a very small portion of an image. Keep one copy for comparison and do repeated Jpeg saves with the other.
After ten saves load both copies into Photoshop and keep enlarging them until you can see any differences. You will need x 10 to find any evidence and even then it will not be significant.
Believe the manufacturers, they knew what they were doing.

Don't waste time worrying, have fun.
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Old Jan 13, 2003, 6:20 PM   #10
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The biggest loss will occur in the camera on first compression. It's not the loss of colour gradation that the eye is most sensitive to, it's also the loss of edge detail on contours, and distortion with geometric structure.

If I shoot trees/woodland and landscape scenes with a lot of detail, I know I've got JPEG compression when I zoom to equivalent 10x8 or larger and see 'puddling' around edges (and 8 bits is fine to see that). I also see artefacts and a lack of smoothness in large coloured areas, particularly sky and digital distortion with structure which is unnatural. On film I see a random grain structure, which I find less objectionable. Many high quality magazines and newspaper pictures are now showing JPEG compression artefacts, look closely - JPEG pollution is all around us!

Iterative saving tests should be checked by applying an edit such as crop or an effect. It's pointless just re-saving the same image, when in fact it's what subsequent editing is making of artefacts which accentuates the effect of JPEG distortions.

Manufacturers sell compression because it saves on memory and processing power. It has no added benefits to the quality of a picture, since it removes information. Memory and processing speed has improved so much that we should be looking for less compression, not the same or more.
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