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josel
Joined: 19 Aug 2005
Posts: 127
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 Posted: Sat Aug 27, 2005 2:56 pm Post subject: SAVING FILES |
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Hi,
I am using photoshop CS2, the question is, what is the best format to save an image, for the best quality and for it to be losless. I am not bothered how large the file is
Kind regards Josel |
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teddc
Joined: 04 Oct 2004
Posts: 389
Location: Belmont North Australia
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| Posted: Sat Aug 27, 2005 3:27 pm Post subject: |
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I always save as tiff, and I NEVER save as jpg. Once a file has been saved as a jpeg it can't be bought back to it's original condition.
ted
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WHAT WOULD VAN GOUGH HAVE DONE WITH PHOTOSHOP |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Sat Aug 27, 2005 5:51 pm Post subject: |
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| teddc wrote: | I always save as tiff, and I NEVER save as jpg. Once a file has been saved as a jpeg it can't be bought back to it's original condition.
ted |
absolutely |
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Gallo_Pinto
Joined: 15 Jul 2005
Posts: 785
Location: BC, Canada
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| Posted: Sat Aug 27, 2005 9:54 pm Post subject: |
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I was of the opinion that jpeg quality 12 produced lossless jpegs. Is that incorrect?
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brush your hair and comb your teeth |
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teddc
Joined: 04 Oct 2004
Posts: 389
Location: Belmont North Australia
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| Posted: Sun Aug 28, 2005 1:11 am Post subject: |
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I'm not sure.
Save an image as 12 jpeg. Zoom right in on one of the channels and see if the artifacts are there.
If so you have lost information. Perhaps a more enlightened person than I can put me right
ted
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WHAT WOULD VAN GOUGH HAVE DONE WITH PHOTOSHOP |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Sun Aug 28, 2005 2:35 am Post subject: |
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Even JPG-12 is lossy. And every time you resave as a JPG-12 the image is recompressed and quality goes down more.
That said, JPG-12 is a very high quality, and you wouldn’t notice much (if any) loss in quality on a normal image.
Here is my test:
Create a 400 px X 400 px RGB file. Draw out a red to white gradient. Save as TIFF. Duplicate that file and save as JPG-12. Close the JPG file and reopen it. Shift+drag the JPG file on top of the TIFF file. Zoom in to 200%, view the blue channel and toggle visibility of the JPG image. You should see distinct banding in the JPG not there in the TIFF image. |
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stevealmighty
Joined: 14 Jul 2005
Posts: 335
Location: upstate NY (WAY UPSTATE!)
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| Posted: Sun Aug 28, 2005 10:55 am Post subject: |
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This is how it was explained to me: .tiff saves all colors, even the colors that the human eye can't see. .jpeg saves only the colors that the human eye can see. It removes color dots that the eye can't see, thus making it smaller in resolution. I should think that whenever an image is saved as a jpeg, there's going to be some loss, for the sole fact that color information has been removed from the document.
Now, psd is supossed to be lossless, although I can't prove or disprove that.
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All gave some, some gave all.....Lest we forget that war produces veterans, wounded both mentally and physically, and it is our job to help them now, as they have already helped us all in ways we will never know, and in ways that we take for granted every day. |
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Gallo_Pinto
Joined: 15 Jul 2005
Posts: 785
Location: BC, Canada
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| Posted: Sun Aug 28, 2005 9:45 pm Post subject: |
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if jpeg is lossy, then why is it used by digital cameras? (other than bacause tiffs are too darn huge)
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brush your hair and comb your teeth |
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SteveS
Joined: 30 Apr 2005
Posts: 38
Location: Calee-fornia
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| Posted: Mon Aug 29, 2005 12:30 am Post subject: |
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what is the best format to save an image, for the best quality and for it to be losless. I am not bothered how large the file is"
That’s an easy one - TIFF
If there is no concern for file size, there should be no reason why one should need, or even consider the need to save as a Jpeg.
Gallo_Pinto said- "if jpeg is lossy, then why is it used by digital cameras? (other than bacause tiffs are too darn huge)"
That’s the main reason, TIFF's are too big. Multiply the camera’s magapixel capacity by three (8 bits per channel), and that will fill up a card quite quick as full TIFF files. Saving as a high to max quality Jpeg really does not show any visible sign of loss to the casual digital camera user. Most digital camera users, I dare say, really don't know the difference.
But, I speak as a slide film user. If I had a digital camera, I would be tempted to save all images as TIFF’s. When will I stop using slide film and switch to digital capture, you ask? When the film is pried from my cold dead fingers! |
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cbadland
Joined: 19 Jan 2005
Posts: 962
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| Posted: Mon Aug 29, 2005 7:00 am Post subject: |
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| Gallo_Pinto wrote: | | if jpeg is lossy, then why is it used by digital cameras? (other than bacause tiffs are too darn huge) |
The better digital cameras allow you to shoot in RAW. TIFF files not only take up a lot room on the camera’s media, but take a long time for the camera to process after the picture is taken. RAW image files (not realy a “format’ per se) are minimally processed files, about half the size, or less, of TIFF files, yet contain much more information. Including high-bit data.
You need special software to “process” RAW files to convert them into a standard image format, like TIFF. The software either comes with the camera, or is supported through Adobe Camera Raw.
For regular digital picture taking, shoot in High Quality JPEG, then convert to TIFF in Photoshop. Edit and archive as TIFF.
Last edited by cbadland on Mon Aug 29, 2005 7:04 am; edited 1 time in total |
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