RAW to TIFF


MX veteran

Link Posted 21/02/2008 - 01:14
Having only just started shooting in RAW, I have noticed on some threads that people save as TIFF file and then appear to do something else with the results. I have been saving to JPEG thinking I have reached the end. Am I missing something. I have so far been amazed what can be acheived by my stumbling efforts with Silkypix and hope to get better as time goes by.
K100D Super, 18-55, 50-200, Sigma 10-20, Sigma 70mm macro and lots of old lenses

iceblinker

Link Posted 21/02/2008 - 02:04
Further processing with another program after Silkypix is only needed if you want certain special effects or special manipulation (cheating!) that Silkypix can't do. Sikypix doesn't have any cloning features, for example.
It's no match for Photoshop for these kind of things. (Not that I have Photoshop myself yet).

If you are going to do any further work, you might as well do it with TIFFs rather than JPEGs as they conain more data. Some data is lost with JPEGs as they use lossy compression.
~Pete

MX veteran

Link Posted 21/02/2008 - 02:09
Ah, I see. I have Corel photopaint which I use for that sort of purpose, like removing marks when I have a dirty sensor. Is that what you mean?
K100D Super, 18-55, 50-200, Sigma 10-20, Sigma 70mm macro and lots of old lenses

iceblinker

Link Posted 21/02/2008 - 02:24
Yes, removing marks, etc, but also the more outrageous stuff people do nowdays like chopping off someone's head and transfering on someone else's body!

That's an extreme example, but you know what I mean. Cheating, I call it!

Seriously, Silkypix is great but it doesn't offer much when it comes to altering just part of the image in isolation - whether that be cloning, blurring, colour and tone changing, distortion, etc. It instead affects the whole image or all parts of the image of a particular tone or colour. You can't ring fence off part of the image and work on that alone.
~Pete

amoringello

Link Posted 21/02/2008 - 02:32
Depending on want you consider "the end", and depending on your "need for image quality", your method may be quite acceptable.

Although technically if you save to JPEG from SilkyPix, load into PhotoPaint/PhotoShop to do modifications, the save again... you are saving JPEG twice which will exaggerate the amount of loss from the original.
But if you only save the one time, the loss is probably not noticeable. (again, depending on photo and how good your eyes or audience's eyes are.)

If you plan to do more complex changes like layering with gradient transparency can cause major degradation very quickly. You may even need to save in 16bit TIFF if you foresee such modifications.
Hopefully mods such as levels/curves adjustments would be a minimum and handled in SilkyPix ahead of time.

Personally, I save to JPEG, unless I see a need to do otherwise.

johnriley

Link Posted 21/02/2008 - 08:00
The basic "rule" is never to save the original as a lossy format such as JPEG. I especially don't see the point of shooting in RAW and then introducing data losses further down the line.

Anyway, once an image has been opened and worked on then if you save in a lossless format, usually TIFF or psd, then you will maintain optimum quality.

The only situation for JPEG is for web use, or perhaps for a printing service that specifies JPEGs.

As I normally shoot in JPEG it would be even worse to save a JPEG again as a JPEG as quality would start to fail.
Best regards, John

amoringello

Link Posted 21/02/2008 - 11:46
If you shoot in JPEG, aren't you setting yourself up for failure? You will most certainly have to save as JPEG again.
Storing as TIFF doesn't add any benefit unless you're storing in-progress works where you may need to save multiple times.

Other than the conversion time, that scenario is identical to shooting in RAW then converting directly to JPEG. Perhaps worse, because you allowed the camera to process the image. SilkyPix probably could have done more for the original JPEG image and produce a better initial JPEG from which to do further work.


Although I do agree that you should consider converting to TIFF (or other loss-less format) if you think you'll be doing more work and saving again.

One extra save in JPEG using maximum quality is really going to loose very little - depending on the image. I'm not sure it always warrants the extra effort to avoid JPEG at all costs.

iceblinker

Link Posted 21/02/2008 - 12:02
With Silkypix, it is no more effort to make a TIFF than a JPEG. The only disadvantage is the larger file size, and perhaps less compatibility with certain things.
~Pete

Ava

Link Posted 21/02/2008 - 12:09
I have just been learning CS, and what I have been doing is to save as PSD after my RAW adjustments. Then I usually go to do some other adjustment layers, and cleaning it up. I usually save in TIFF or PSD before and after I flatten my image. I only make jpegs for saving on the web or emails. I just read that it was better to save in PSD or TIFF to retail data. I am still learning myself.

MX veteran

Link Posted 21/02/2008 - 14:45
Using Coral, if you work on a JPEG, when you save that work you can choose the amount of compression. If you use 0% compression it does not alter the image quality. I have just tried this by saving a JPEG image repeatedly over 40 times and comparing the 1st and last save. No change to quality.
K100D Super, 18-55, 50-200, Sigma 10-20, Sigma 70mm macro and lots of old lenses

johnriley

Link Posted 21/02/2008 - 14:46
Quote:
If you shoot in JPEG, aren't you setting yourself up for failure? You will most certainly have to save as JPEG again.

This is a huge can of worms to open, but the short answer to the first question is "No." and to the second is "Why?"

We have re-tested extensively since the K10D came out and comparative shots in RAW and JPEG from the camera make very little difference to an A3 print and the advantage can go either way depending on the subject. The idea that we must shoot is RAW to get great quality is just not right.

Why would I need to save anything at any stage as a JPEG? As soon as the JPEG from the camera is opened and worked on every save after that is a TIFF. The exception is use for web, when a small JPEG can be made from the finalised TIFF,
Best regards, John

MX veteran

Link Posted 21/02/2008 - 15:16
Here are some before and after JPEGS
They were taken in JPEG
Before



After 45 saves in JPEG using 0% compression



Cropped before



Cropped after



I can detect no difference.
K100D Super, 18-55, 50-200, Sigma 10-20, Sigma 70mm macro and lots of old lenses

George Lazarette

Link Posted 21/02/2008 - 18:59
I believe that JPEG is only a lossy format if you save at less than 100%.

G
Keywords: Charming, polite, and generally agreeable.

mikew

Link Posted 21/02/2008 - 19:02
I'm probably revealing some deep seated ignorance here but I thought that any image saved as JPEG had to go through some software algorithm to take the RAW saved from the sensor and create the JPEG file.

I'd have thought that a hard coded algoithm in the camera would almost certainly be less capable than a good quality RAW coverter such as SilkyPix. I just can't see how what must be a pretty feeble computer in camera can compete with some swanky dual core system running optimised code for the generation of TIFF/JPEG from RAW.

I guess that the manufacturer can produce very efficient code for use in camera but third party programmers will almost certainly be able to make a better job of it.

As I say I'm probably wrong but I'd like someone to explain why!

Mike

Malo1961

Link Posted 21/02/2008 - 19:10
If you read this:http://www.luminous-landscape.com/tutorials/understanding-series/u-raw-files.shtml
You know the answer. Pay extra attention to the part explained in figure 1 and 2 . And use real prints to check quality of tiff's against jpeg's. Comparison on a monitor is useless.
Enjoy,
Martin.
Best regards,

Martin.


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