PP and file format experts please

[michaelb]

OK, I'm really confused by this one. I have always understood TIFF to be a lossless format. I noticed something odd so I did a little test.

RAW image - converted to two identical TIFF files.

Image #1: Converted from TIFF to jpeg, 100% crop made.

Image #2: TIFF file edited (saturation, contrast, then edits undone). Converted from TIFF to jpeg, 100% crop made.

Why is the second image degraded compared with the first? Look at the shingles and the bricks the middle - detail has been lost. I also did this test with an edited jpeg and there was even more degredation, as expected. But if TIFF is a lossless format then the two images should be identical, but clearly the second image has been damaged.

Any ideas?





http://brownphotography.smugmug.com/photos/252793960_hbYZZ-L.jpg

[TenD]

I am interested to know the answer to this too. I always thought .tiff was lossless as well. I definitely see a degradation in photo #2.

[michaelb]

I am interested to know the answer to this too. I always thought .tiff was lossless as well. I definitely see a degradation in photo #2.

Normally I wouldn't worry too much about this as its unlikely to be noticable in normal sized prints, but I want to make some big landscape prints and I really don't want to loose any detail in such large prints, where it is more likely to be noticable.

I'm really stumped by this one.

[griptape]

What software are you using?

[michaelb]

What software are you using?

I'm using PSP X.

[D Thompson]

I can see it in the one you posted, so I tried it myself. I don't see any difference in mine. I don't use PSP so am wondering if it is the culprit and maybe not undoing your edits. :confused:

I took a RAW file, saved in ACR as a tiff file 2 separate times with same settings. Opened tiff1 and saved as a jpeg. Opened tiff2 and ran 4 or 5 adjustmenst and undid the edits so I'm back to original and saved as a jpeg. Opened both jpegs and cropped to 600x600 pixels.

[fractalgfx]

OK, I'm really confused by this one. I have always understood TIFF to be a lossless format. I noticed something odd so I did a little test.

First, the TIFF format can be lossless or lossy, it depends on the compression method. Uncompressed TIFFs are lossless, as are deflate and lzw compressed tiffs. Tiffs can also use the lossy jpeg compression algorithm.

Second, your methodology is flawed. You can't make any judgments about the quality of the tiff format after converting the image to a JPEG. JPEG artifacts (glitches in the compressed image) vary based on the original image, compression settings, and the software used to create them. By modifying the original image you caused a different set of jpeg artifacts to be produced.

What you did would be like comparing two high quality photographic prints based on xerox copies.

[JTL]

Michael,

Since you're shooting RAW, unless you're sending your images to a publication that requires tiff, I see very little reason to use it. Unless you need to use layers for some reason, all your edits can be performed non-destructively in your RAW software...both Lightroom and Capture One have outstanding editing flexibility Then, only output to jpeg when necessary to print or display.

[JMWallace]

WOW, this is of particular interest to me.

Of lately, I have been shooting RAW. Doing basic exposure and white balance adjustments in Lightroom. Then exporting the file to a .TIFF file. From there (since assuming it is a lossless format) editing the 16 bit .TIFF in PS CS2. Once my edits are done, I then convert it to "high res" 300 dpi .jpg for upload to my site (which Smugmug adjusts for display purposes) which is then used for printing if someone buys.

I will say that I did have someone buy a 16x20 and they were thuroughly impressed and absolutely ecstatic about the final product; but, I did not see the end result.

Is my methodology flawed?

[Squirt]

I think D Thompson probably hit the nail on the head. Depending on the tiff whether it's a 16 bit or a 12 bit, you are going to have degradation going to a jpeg with either. You are going to have more going from a 16 bit because the jpeg process will compress the color data more and hence create more artifacts.

[Mark_48]

I've got PSP and tried to replicate the steps that were done and the resulting images were the same with no apparent deterioration. Are the file sizes of the two JPG's same or are they significantly different?
Maybe look at your settings preferences and see if there's anything suspicious. The save option for a TIF can be LZW or uncompressed. Could Autosave be enabled and it saved as with LZW compression?

[fractalgfx]

I've got PSP and tried to replicate the steps that were done and the resulting images were the same with no apparent deterioration. Are the file sizes of the two JPG's same or are they significantly different?
Maybe look at your settings preferences and see if there's anything suspicious. The save option for a TIF can be LZW or uncompressed. Could Autosave be enabled and it saved as with LZW compression?

Makr LZW is lossless.

[cdifoto]

WOW, this is of particular interest to me.

Of lately, I have been shooting RAW. Doing basic exposure and white balance adjustments in Lightroom. Then exporting the file to a .TIFF file. From there (since assuming it is a lossless format) editing the 16 bit .TIFF in PS CS2. Once my edits are done, I then convert it to "high res" 300 dpi .jpg for upload to my site (which Smugmug adjusts for display purposes) which is then used for printing if someone buys.

I will say that I did have someone buy a 16x20 and they were thuroughly impressed and absolutely ecstatic about the final product; but, I did not see the end result.

Is my methodology flawed?

Right or wrong, I dunno. But I don't even mess with big honkin' TIFFs unless I scan something. I go RAW --> JPEG.

[michaelb]

.....

Second, your methodology is flawed. You can't make any judgments about the quality of the tiff format after converting the image to a JPEG. JPEG artifacts (glitches in the compressed image) vary based on the original image, compression settings, and the software used to create them. By modifying the original image you caused a different set of jpeg artifacts to be produced.
....
I started with a sinlge RAW image and made two identical TIFF copies. I edited one of the TIFF files, but then undid the edits (undo function). Thus both TIFF's should have been the same prior to jpeg conversion. I then converted both files to jpeg. If the TIFF that was edited wasn't damaged then the two jpegs should be identical and they are not.

I think D Thompson probably hit the nail on the head. Depending on the tiff whether it's a 16 bit or a 12 bit, you are going to have degradation going to a jpeg with either. You are going to have more going from a 16 bit because the jpeg process will compress the color data more and hence create more artifacts.
Again, both files went through the same sequence, thus if there was degradation fo the images, then the degradation should be the same and both jpegs should be the same.

I've got PSP and tried to replicate the steps that were done and the resulting images were the same with no apparent deterioration. Are the file sizes of the two JPG's same or are they significantly different?
Maybe look at your settings preferences and see if there's anything suspicious....
That's interesting Mark. I repeated this test several times and got the same results.
The jpegs are the same size, same compression.
I'll have a look at the settings, but again I used the same process for each image, so if there was degradation it should be equal between the two images.

Michael,

Since you're shooting RAW, unless you're sending your images to a publication that requires tiff, I see very little reason to use it. Unless you need to use layers for some reason, all your edits can be performed non-destructively in your RAW software...both Lightroom and Capture One have outstanding editing flexibility Then, only output to jpeg when necessary to print or display.
I use DPP as my RAW editor and I use it to fix WB, saturation, etc but there are things it can't do, like straighten images, curves. Thus I figured that I would make these changes on a TIFF file in PSP so I wouldn't damage the image as a jpeg.
By the way, I also did mulitple edits and undid them on a jpeg and I was shocked by how much fine detail was damaged.

Again, normally I wouldn't care about any of this, but I want to make some big prints and thus I want the best IQ possible out of my images.

[JTL]

...but there are things it can't do, like straighten images, curves.A program like Capture One lets you do all that in RAW...thus cutting a HUGE (both in time and disk space) step out of your workflow. Plus the results just look better (especially things like NR and sharpening). And, as stated previously, ALL edits in Capture One (and Lightroom) are non-destructive...it's just a better (IMO) way to work. ;)

[cdifoto]

You can do curves in DPP. Go to the RGB tab in the toolbar.

[michaelb]

A program like Capture One lets you do all that in RAW...thus cutting a HUGE (both in time and disk space) step out of your workflow. Plus the results just look better (especially things like NR and sharpening). And, as stated previously, ALL edits in Capture One (and Lightroom) are non-destructive...it's just a better (IMO) way to work. ;)
Yea, I probably should get something like Caputure One or Lightroom, but DPP is free and many say is does the best job in terms of RAW conversion.
Maybe I should get a trial of Capture One or Lightroom to check it out.
I'm a cheap bastard though and I hate paying for software. :D
Are many of you guys still using DPP?

I'm still bothered by the apparent damage to my TIFF files however, without a good explanation for it. I've always liked PSP - it will do 95% of what Photoshop does at a fraction of the cost and it blows Elements out of the water. But this TIFF isssue bothers me.


You can do curves in DPP. Go to the RGB tab in the toolbar.
Your right Don, I forgot about that - thanks.

[cdifoto]

Yea, I probably should get something like Caputure One or Lightroom, but DPP is free and many say is does the best job in terms of RAW conversion.
Maybe I should get a trial of Capture One or Lightroom to check it out.
I'm a cheap bastard though and I hate paying for software. :D
Are many of you guys still using DPP?

I use Lightroom because I was grandfathered in from the RSP days. If that weren't the case, I probably wouldn't have it since I too am cheap when it comes to buying software. I'm still using PS7. :eek:

[Mark_48]

I tried another attempt to get screwed up JPG's and no luck. Even tried an effect which took the 16 bits and reduced it to 8 bits, but undoing it reverted it back to 16 bits.
I have however found in this experiment, that an old version of ACDSee I use for quick browsing doesn't particularly like TIF files even though it opens them. Note the image below. What was once a nice deep blue sky is now....... :eek:

Probably not related to the problem. PSP X has an update (v10.02) that addresses a few things in the file format. Maybe you've already updated(?)

From Corel's site....

File Format Improvements:
- Copyright data added in the Image Information dialog is now correctly saved in TIFF or JPEG files.
- Saving files as TIFF will no longer result in loss of the image resolution value.
- Problems reading 16-bit multi-page TIFF files have been fixed.
- When opening a Camera Raw image by double-clicking the file icon in - Windows, the auto-rotate and Smart Photo Fix options now work.
- Problems saving photos that were previously accessed using Nikon browser software have been fixed.
- Fixed problems rendering transparency in .eps and .ai files.
- Fixed a problem where saving a 16-bit/channel image as BMP required changing the image to paletted (256-color) mode.
- Paint Shop Pro now correctly opens Windows Cursor (.cur) files.
- Problems loading certain TGA files have been fixed.
- PNG files now correctly list resolution values as PPCM (pixels per cm) instead of PPI (pixels per inch) when metric units are used.

[Squirt]

I'm using Aperture for all my work. Very seldom do I work anything other than a RAW file or a version of the master. We shoot Jpeg's with our p&s Olympus but generally they go to 4 X 6 only.

[fractalgfx]

When you open and close the two TIFFS are they identical?

[michaelb]

You guys are going to think I am a complete loon, but I did the whole test over again with two new TIFF files, created from the original RAW file and now the two are identical.

I think I'm loosing my mind. Thanks for all your input guys. I honestly don't know what I did differently to get a different result, but.....





http://brownphotography.smugmug.com/photos/253499768_EkgDP-M.jpg

[Vich]

.... TIFF file edited (saturation, contrast, then edits undone). ...

That seems contrary to the objective. What does "edits undone" mean?

I would think opening then re-saving many times would zero in on the TIFF format issue.

The approach of making changes then "undoing them" could mean a dozen things, many of which would likely add up to some edit algorithm monkeying with bits, then re-monkeying with them for the "undo".

Good points above on 12 bit vs 16 bit. Since most cameras go 12 or 14 bit, then using the far larger 16bit TIFF format does seem an awful and counter-productive waste.

[Squirt]

Glad it worked out for you, Michael.
Vich wrote:
Good points above on 12 bit vs 16 bit. Since most cameras go 12 or 14 bit, then using the far larger 16bit TIFF format does seem an awful and counter-productive waste.

Most cameras use either a 12 or 14 bit analog to digital converter. In the case of a 12 bit converter it produces a value between 0 and 4,096, with a 14 bit converter it produces a value between 0 and 16,384. While this doesn't increase the dynamic range of the camera, the brightest and darkest colors will be the same, the extra bit depth will produce finer graduations within the dynamic range. While you may capture in 12 to 14 bit depth, when you convert to JPEG you lose most of the information. JPEG images only allow 8 bits or a value of 0 to 256. The resulting image will have less room for editing, because it will more quickly yield artifacts. When you convert to that big honking 16 bit file, while you don't increase the amount of information, you also preserve all of the color information that was captured, allowing you more editing latitude.

[michaelb]

That seems contrary to the objective. What does "edits undone" mean?

I would think opening then re-saving many times would zero in on the TIFF format issue.

The approach of making changes then "undoing them" could mean a dozen things, many of which would likely add up to some edit algorithm monkeying with bits, then re-monkeying with them for the "undo".
...

I noticed some degradaton of edited images, which is why I ran this testing. I simply wanted to know if the TIFF file would be damaged by these edits/unedits. This is the way I will often do it in "the real world". I will make a change, but then not like the way it looks and use the undo command to undo that change and I wanted to make sure these types of edits weren't damaging the file.

[michaelb]

Glad it worked out for you, Michael.

Lesson #1: No more than one glass of wine before PP. ;)

Serioulsly though, I really don't know why I got differing results. Something must have been selected differently.

Thanks for all of the input guys.


Most cameras use either a 12 or 14 bit analog to digital converter. In the case of a 12 bit converter it produces a value between 0 and 4,096, with a 14 bit converter it produces a value between 0 and 16,384. While this doesn't increase the dynamic range of the camera, the brightest and darkest colors will be the same, the extra bit depth will produce finer graduations within the dynamic range. While you may capture in 12 to 14 bit depth, when you convert to JPEG you lose most of the information. JPEG images only allow 8 bits or a value of 0 to 256. The resulting image will have less room for editing, because it will more quickly yield artifacts. When you convert to that big honking 16 bit file, while you don't increase the amount of information, you also preserve all of the color information that was captured, allowing you more editing latitude.

Nice explanation of this subject, thanks.

[Vich]

Glad it worked out for you, Michael.
Vich wrote:


Most cameras use either a 12 or 14 bit analog to digital converter. In the case of a 12 bit converter it produces a value between 0 and 4,096, with a 14 bit converter it produces a value between 0 and 16,384. While this doesn't increase the dynamic range of the camera, the brightest and darkest colors will be the same, the extra bit depth will produce finer graduations within the dynamic range. While you may capture in 12 to 14 bit depth, when you convert to JPEG you lose most of the information. JPEG images only allow 8 bits or a value of 0 to 256. The resulting image will have less room for editing, because it will more quickly yield artifacts. When you convert to that big honking 16 bit file, while you don't increase the amount of information, you also preserve all of the color information that was captured, allowing you more editing latitude.
Yes, thanks for the explanation.

I think the point was that, when you do the reduction from 12/14/16 bit down to 8, would the impact (noticeable loss) be less coming from 12 to 8 vs. 16 to 8. I do not know the answer.

Michael; I see your point, that it's real-world degradation that you're concerned with. The point raises a number of questions like; does the editing program actually work in TIFF (or JPG or ...), or does it convert to some intermediary "working format" that is subsequently saved in a selected format? In short; the answer could vary widely depending upon the editing program used.

[Squirt]

The files should be the same wether you come from 16 bit or 12 bit. They will all be converted down to the same JPEG file if you use an identical compression ratio. You would just lose more color range in the 16 bit versus the 12 bit.