[HUG ] Re: IMG: Triptych

There seems to be a general opinion that any manipulation done by software on the raw data is somewhat bad and "corrupts" it. I think that this is the point I do not agree with and it is what I had in mind when I asked my question in the first place.
Incidentally, we should talk about software and not firmware. Any output, including raw, is affected by "firmware tweaks". Without firmware the machine simply does not work, let alone write files.
Anyway, both the various raw files formats and the 16/48 bit tiff format are capable of storing the same amount of data in the strict numerical sense. If we make an analogy with languages, they are different languages based on the same alphabet and having the same number of words.
What this means is that for the two types of files there is the same (lack of) difference between what you see on your screen and what actually is in the file. This is not the case for instance in compressed formats like jpeg. You can think of a raw and a tiff file as two boxes which can contain the same amount of data. When you save to tiff as opposed to raw, you are not "losing" information, you are just saving "different" information. My point is that this is different information is not of lower quality; it is still a file which contains 16 bits for each colour for each pixel in your scanner's sensor.
However, the image contained in the tiff file (which has had some lossless manipulation by the scanner software) is closer to what you eventually want to print or display. If, suppose, your negative is slightly underexposed, in the raw case your file will not have any "pure white pixels", so effectively you are not using all the "letters" in the alphabet. When you later work on the file in your image editor you will set the white point at the lightest luminosity value in your file. When doing this you are indeed losing information by "stretching" your histogram.
There is an essential difference between a scanner and a digital camera. In the camera it is the same data captured by the sensor and stored in two different ways. Then I understand that one may not want the camera to do any manipulation on the data. In the case of the scanner, however, when working with tiff output you have some control on what your saved image looks like, which do not have in the raw case. It is as if you could change the light in you camera capture when writing the data to tiff.
If there are advantages in working with dng files in Lightroom for instance, then it seems to me that the best way to proceed would be to save the "best possible" data into the scanner output (which is capable of containing the same "amount" of data in either format). This means using tff. Then convert looslessly (is this English?) to dng, say in Camera Raw, and import the dng file into your image editor.
There is also a point in saving all scanned images in dng format as there is a chance that this will indeed become the standard. 

Regards,

Stefano

P.S. Sorry, this turned out to be much longer than I thought.
P.P.S. Bob, I meant to make the same suggestion about colour matching in the three panels. The triptych looks very nice and I am sure that it is great in print, irrespective of the format of your scans... 


On 18 Mar 2009, at 02:03, Jim Brick wrote:
One thing, LR2 deals with DNG differently than TIFF. This isn't saying that you cannot do exactly the same with both, but, for instance, LR color temp slider gives the 'color temperature value' (in Kelvin) for RAW and DNG. And if you have a photograph taken via tungsten, the slider will be way to the left and tell you that it is, say, 2850K. but for a TIFF, it just gives the slider set at zero (the middle) and you adjust + or -. There are other differences as well but this one is easy to explain. I personally like the actual temperature being given including that the slider is positioned analogically where it is supposed to be, on the scale from 2000 to 50,000. I know, I'm simple and easy to please, but when my scans operate within LR or PS in exactly the same manner as camera RAW files, I like that!
I have a 6x6 tranny that I scanned, on the same scanner, as a TIFF and as a DNG. The DNG wins! To LR, it is the same as a RAW file from a camera. You really don't know that you are working with a scan since everything works the same. I like it (I guess you can tell...)!
Now, on the Imacon, the RAW file is a .fff file, but written in TIFF format so that programs other than 'FlexColor' can read them. So other than with Photoshop, you have to change the file extension from .fff to .tif. But as I said earlier, it is really obvious that it is a raw file! Ugly!!! 

JMHO,

Jim


On Mar 17, 2009, at 7:25 PM, Austin Franklin wrote:


Hi Jim,
I don't know what Vuescan does to the .tiff files it saves (when they call 
them "raw", I would hope nothing, but perhaps not?)...but there is
absolutely no reason that a .tiff file can not contain the exact raw image as captured from the scanner A/D, with no processing (except for calibration similar to PRNU in the digicams). In fact, the Leafscan saves "raw" data as 16 bit .tiffs, which are called "HDR" (High Dynamic Range, since they are 16 bit/pixel). But, IME, there is really no need to do that if you get your 
setpoints and tonal curves right in the first place.
I don't see the need for a special ".dng" format, when a .tiff can support 
exactly the same thing...except to sell a "pro" version of Vuescan...

Regards,

Austin


-----Original Message-----
From: hasselblad-bounce@xxxxxxxxxxxxx
[mailto:hasselblad-bounce@xxxxxxxxxxxxx]On Behalf Of Jim Brick
Sent: Tuesday, March 17, 2009 7:54 PM
To: hasselblad@xxxxxxxxxxxxx
Subject: [HUG ] Re: IMG: Triptych


To get a RAW file from a scanner using Vue Scan, you have to buy the
pro version of Vue Scan, then select that the file be written as a DNG (Digital NeGative) which tells Vue Scan to ignore all of the Vue Scan pre-sets and just write the 'raw' scanner data to the file. This is a true raw file in DNG format. It's purpose is actually for re- scanning the same image but without putting the film into the scanner. You scan 
the DNG file, which comes into Vue Scan as if it came from the
scanner, with Vue Scan pre-sets set to the way you want them, and then get a TIFF or JPEG, or whatever, with the changes that you want. This 
presumes that you use Vue Scan as your image processor.
So... Vue Scan DNG is truly RAW scanner data! No firmware or software tweaks, only the gathering of the bits and putting them into a file in 
DNG format.
For me, it's much easier to get the picture that you want via LR or PS rather than trying learn all of the nuances of a scanner program. I'll 
take my digital images RAW!

Jim


On Mar 17, 2009, at 5:16 PM, Austin Franklin wrote:


Hi Franc,

But...as both Marc and I pointed out, there is no such thing as a
standardized "raw" file format, but as I've pointed out, they can be 
saved
as TIFFs. And, taking you up on your suggestion, what it appears
from the
Vuescan's manual, is that it saves these "raw" files with a .tif
extension:

"• In the Output tab un-check all the options except for Output >
Raw file
As each image is scanned, files with sequential numbering such as
scan0001.tif,
scan0002.tif, etc. will be created."

"To re-process these raw files:
• Set the Input > Source option to File, and set Input > Files to
point to
the starting file
in the series (eg scan0001.tif)"
So, at least with Vuescan, these "raw" files are saved as TIFFs, and 
there
is, obviously, no loss of data with these TIFF files.

Regards,

Austin


-----Original Message-----
From: hasselblad-bounce@xxxxxxxxxxxxx
[mailto:hasselblad-bounce@xxxxxxxxxxxxx]On Behalf Of Franc Flipsen
Sent: Tuesday, March 17, 2009 6:10 PM
To: hasselblad@xxxxxxxxxxxxx
Subject: [HUG ] Re: IMG: Triptych



I have a epson V700 and a minolta scan multi II and they both save
in raw
format using Viewscan and infact you can save as raw from any
scanner with
viewscan, Maybe you should check it out at www.hamrick.com .
I've also used
it with a polaroid sprintscan 45.  I can get a 48bit multi-pass
scan from
all of these scanners.  Of course they need to be saved as raw
files or you
loose information in conversion to a tiff file format.

Franc


----- Original Message -----
From: "Austin Franklin" <austin.franklin@xxxxxxxxxxx>
To: <hasselblad@xxxxxxxxxxxxx>
Sent: Tuesday, March 17, 2009 4:48 PM
Subject: [HUG ] Re: IMG: Triptych



Hi Franc,


I think the point he is trying to make is that when you scan or
capture if
you save it in Raw you get what the sensor saw at the time and if 
you save
it to a tiff, dng or some other format you discard some of the
data.


Sure, but that is not true with TIFF when talking about a

scanner, which

is
what I was questioning.


tiff
is a lossless format when opened but some of the data (not

needed by the

tiff file format)is stipped off the file before it is saved


Like what data?  If any data is "stripped" that is implementation
dependant.
I have a few scanners that save TIFF, and that is THE raw data

format for

these scanners.  These TIFFs are typically called "HDR" for High
Dynamic
Range.  IOW, they have no setpoints or tonal curves

applied...so the image

you see if you were to open the file up in, say, PS, will be
typically
very
dark...until you apply setpoints and tonal curves to "normalize" it. 


...so
the tiff file
does not contain all the data the sensor saw but a raw file does
contain all
the data the sensor saw and nothing else, not even a color

space profile.
Well, that's not necessarily true. At least with the scanners I've 
designed
and the ones I have.  To save a "raw" file with any of my
scanners, you
save
it as a TIFF file, with no setpoints or tonal curves set.  TIFF
does not
define a "color space profile".

What scanner do you have that saves files as "raw" and it's not
HDR or
TIFF?

Regards,

Austin




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