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Topic: changing pictures from Jpeg to Tif |
Buck Grantham R.I.P.
From:
Denham Springs, LA. USA
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Posted 27 Jun 2006 7:08 pm |
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| To change pictures from Jpeg to Tiff,do you have to Make adjustments in the computer or the camera. I want to save pictures in the computer as Tif files to Preservr the quality of the picture.Thanks for any help I can get on this. I looked in the computer and all of my pictures are Jpeg. |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 27 Jun 2006 8:16 pm
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Your camera will have a setting to choose the format to which files will be saved. Choose TIF.
To convert JPEG (lossy) files into TIF files (not lossy) you should have saved the JPEGs at 100% quality, otherwise you will lose a lot in the conversion process. If the files were saved a a lower quality there is no real point in saving them as TIFs, as the quality will suck.
Use your graphics editor to Save As filename.tif. Again, this only makes sense if you saved the originals at full fidelity.[This message was edited by Wiz Feinberg on 27 June 2006 at 09:16 PM.] |
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Jeff Agnew
From:
Dallas, TX
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Posted 28 Jun 2006 4:41 am
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| you will lose a lot in the conversion process. |
Why? |
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Ernest Cawby
From:
Lake City, Florida, USA, R.I.P.
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Posted 28 Jun 2006 4:53 am
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Because they were poor quality to start with, every time you convert you lose .
ernie |
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Dave Potter
From:
Texas
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Posted 28 Jun 2006 4:54 am
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| Your camera will have a setting to choose the format to which files will be save |
Many, including my Canon 6.3 MP, do not have that option. Mine, and others, can only produce images in Jpeg and RAW formats.
The main problem with "lossless" image formats is that they produce HUGE files, taking up much more space on camera memory cards and PC hard drives. Use of the jpeg format addresses this issue. Jpeg does use compression to reduce the size of an image, but capture at the highest quality/resolution available will initially have a nearly imperceptible loss of detail compared to a tif file with similar resolution.
A jpeg image will not lose any further detail/quality unless it is saved again; each successive "save" will result in data loss. This can be avoided by saving an edited jpeg to a lossless format like png, tif or psd.[This message was edited by Dave Potter on 28 June 2006 at 06:28 AM.] |
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Ray Minich
From:
Bradford, Pa. Frozen Tundra
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Posted 28 Jun 2006 4:55 am
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Some cameras and their "downloading" programs have a "native-uncompressed" format. My old Kodak DC-50 had that. You could also transfer as tiff or jpg but the native Kodak format was totally maxed to the pixels of the camera.
Going jpeg is kinda like recording to mp3 and then making a .wav out of it... The .tif may be the most detail. Jpeg is compressed, and a lossy compression. Save the file in the least compressed/most uncompressed format (i.e. native, or .tif (Tag Image File Format)) if you want all of the original detail.[This message was edited by Ray Minich on 28 June 2006 at 08:03 AM.] |
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Buck Grantham R.I.P.
From:
Denham Springs, LA. USA
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Posted 28 Jun 2006 7:05 am
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| Hey guys !!!! Thank you all so much for the help. I really appreciate it !!! |
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Jeff Agnew
From:
Dallas, TX
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Posted 28 Jun 2006 2:48 pm
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| ...every time you convert you lose . |
No, there is no loss when converting to a lossless format like TIFF. I was curious why Wiz thought this was so. I would agree that if the originals are of poor quality there would be no quality gain by saving as TIFF. But you would have an exact copy of the original, which could be helpful in some situations requiring extensive post-processing. |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 28 Jun 2006 4:39 pm
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Here's my take on the matter of saving images as a different format.
Case #1:
The original file is a .TIF, .BMP, .RAW, .PSD (Photoshop). Let's call these Hi-Q files.
All of these are high quality, full range formats, some with more information storage capabilities than others (separate layers). All of these formats can be edited multiple times and saved, without automatically suffering from a loss of quality. Furthermore, most of these formats have a very large file size, in order to maintain their internal databases about the composition, color bit depth and properties of layers, of the image.
You can edit any of these file formats to your heart's content and save the results to the original, or save to a new file name or file type. If you edit a .TIF or .RAW image, then save it as a .JPG you will automatically suffer some loss of quality. Why? Because .JPG files compress the redundant bits of replicated data to reduce the output file size. However, if you save a Hi-Q file as a 100% quality .JPG the loss will be insignificant for all intents and purposes.
As proof that something is lost the second you save a .TIF as a .JPG, I opened a scanned .TIF of a 4" x 6" photo in ImageReady. The file size is exactly 919,982 bytes. I opened a 2-up view and saved the Optimized version as a .JPG at 100% quality, with no blur, Optimized, not progressive. It's file size on disk is 226,432 bytes. That is a difference of 693,550 bytes. Those eliminated bytes contained information about the image and it's properties; information that has now been stripped out.
If I am happy with the saved result and use it as-is nobody will see any difference between the TIF and the 100% JPG. But, if I edit the JPG, say crop it to get rid of extraneous content, sharpen it, adjust the gamma, contrast and brightness, enlarge it slightly, then save it again, the quality will be diminished. Each saved edit will further compress that image file, even though I save it at 100% quality. That is why JPGs are called Lossy file types. 100% in a JPG is not the same as 100% in a TIF, RAW, BMP, PSD file. Something is always lost each time you save any edits, or resize it.
Case #2:
You start with a Hi-Q JPG saved from a digital camera.
Assuming your camera can output JPGs at 100%, you say want to save these images as TIFs. Using my example images again, I open the 100% JPG in Adobe Photoshop. It allows me to Save As a TIF, which I do. The new TIF has a file size of exactly 470,072 bytes. That is about one half the file size of the original TIF. Almost 50% of the information about the image has been lost by converting it to a JPG, then back into a TIF.
The only benefit of this is that you can now edit the TIF as much as you want, then save it as a JPG when you are finished. You will only lose quality when you save it as a JPG, not while you edit it. If you keep it as a TIF it will not degrade any further, unless you blur or over-sharpen it with a filter.
All JPG files lose quality and information each time they are saved. TIFs only lose information if it is stripped away by your editing or filters. I am guessing that Raw format images contain similar information to TIFs.
Epilogue:
Editing JGP files compounds their natural compression algorithm and degrades the image quality each time they are saved. TIF and RAW files are very large files that contain huge amounts of fine details that allow images to be edited multiple times without inherent losses. Shooting and saving photos as RAW images consumes a lot of memory, limiting the number of shots that can be saved to a given memory device.
One solution to this is to buy the largest, fastest writing memory card that your camera can record to, allowing for more RAW shots to be recorded. Another solution is to carry several smaller, faster cards and use them like rolls of film.
Just my opinions, along with facts from Photoshop and ImageReady results.
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Bob "Wiz" Feinberg
Moderator of the SGF Computers Forum
Visit my Wiztunes Steel Guitar website at: http://www.wiztunes.com/
or my computer troubleshooting website: Wizcrafts Computer Services,
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[This message was edited by Wiz Feinberg on 28 June 2006 at 05:41 PM.] [This message was edited by Wiz Feinberg on 28 June 2006 at 05:43 PM.] |
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Jeff Agnew
From:
Dallas, TX
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Posted 29 Jun 2006 4:39 am
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Wiz,
I wasn't questioning whether saving as JPEG loses information. It does. Although there is a significant school of thought amongst the pro photo community as to whether the difference (when using high quality gear and workflow) is discernible to the naked eye, even after repeated saves. Personally, I don't care. Memory is cheap enough these days that I always shoot RAW when possible.
My question was why you felt that saving an existing JPEG as TIFF would further degrade the image. Here's how you can prove it won't:
Take a JPEG of any quality and save it as a TIFF. Open both images in Photoshop. Copy and paste the TIFF image as a new layer on top of the JPEG. Set the Blend mode to Difference. You'll get nothing but black, meaning the two layers are identical.
| Quote: |
| I am guessing that Raw format images contain similar information to TIFs. |
Actually, RAW images are straight dumps from the camera's sensor. Cursory explanation here. Adobe's site has a better and more technical discussion of RAW.
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| Shooting and saving photos as RAW images consumes a lot of memory, limiting the number of shots that can be saved to a given memory device. |
Yes, although not as much as one might think. Some RAW formats (Canon's among them) use lossless compression and aren't too bad size-wise. Especially when compared to a JPEG saved at 100% quality.
To get back to Buck's original question, if he's wanting a format to preserve whatever quality is in the camera's orginal JPEG, then TIFF will indeed be a good choice if he has the disk space to accomodate the files. |
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Dave Potter
From:
Texas
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Posted 29 Jun 2006 7:53 am
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| Quote: |
| To get back to Buck's original question, if he's wanting a format to preserve whatever quality is in the camera's orginal JPEG, then TIFF will indeed be a good choice if he has the disk space to accomodate the files. |
This is true. But it's worth pointing out that, if all he (or anyone else) wants to do is LOOK at the images, not edit and do repeated saves on them, nothing whatsoever is gained by converting them to anything else, and converting to tif would mean a net loss of available storage space. |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 29 Jun 2006 8:37 am
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Jeff;
Thanks for posting that tip about comparing the differences between two image formats by using Photoshop layers and viewing the difference. |
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