proper way to convert from linear gamma negatives?

[JJackson382]

I vaguely recall someone raising this issue with the SD-II in the dim
distant past, but I couldn't find a reference to it on Google.

IIRC, the input-dpi *is* what you actually get: that is what the scanner
captures the data at. The output resolution is merely a single number
that the scanner driver writes to the resulting file and is, in almost
all cases, completely irrelevant. There isn't much call for 1:1 digital
reproduction of 35mm frames. ;-)

The "output-dpi" is merely a scaling figure, it has nothing whatsoever
to do with the resolution the scanner operates at. If you examine the
image size in your output file you will find that at 2400dpi it is
actually larger than the original frame.

There is a similar discussion about such useless output resolution
figures going on in the thread called "Image does not report the same
resolution at which it is scanned" at the moment. It is superfluous
information in all but a few special cases.

Kennedy, you are right on the money.

Minolta's (mis)use of "output-dpi" has confused many a user. On my 5400,
the max "input-dpi" is 5400 but the max "output-dpi" is 4000. To make
things worse, in the PS CS File Browser, the File Properties Resolution
will also show 4000 even when the scan is at 5400. But if you do some
math, the File Properties' Width and Height (pixel counts) as well as
the File Size will all prove that the scan is at 5400. Also, if you go
to Image | Image Size, you will see the same Width and Height pixel
counts there. When in doubt about resolution, count the pixels and do
the math.

To scan at the max resolution on a Minolta, just set the "input-dpi" to
the max value and ignore the "output-dpi" value. There is no need to
make any change to the scan file as suggested by another poster. Not
sure what the change will do to the data, but it can't be anything good.

 

[Don]

I intensely dislike scanner (or any!) software which is "bossy" but to
prevent you from even scanning at the native resolution of the scanner
would be a new low!! Anyway, I see others more familiar with Minolta
software have already posted the solution.

BTW, I forgot to mention last time but my software only works on
Nikons so it wouldn't be much use on a Minolta anyway.

As to Vuescan's clipping, you will get a much better response here
than writing to the author!! It's been reported repeatedly that he
usually ignores email so some people suggest asking for confirmation.

But there are some very knowledgeable Vuescan users here so posting
your questions is a much safer bet. Even though this is not a Vuescan
group it's often being discussed here because of all the many Vuescan
bugs and general lack of reliability.

Don.

 

[Mendel Leisk]

The one advantage I see of haveing the output dpi of Elite 5400 (for
example) set to 5400, is if you're outputting 16bit linear for use as
Vuescan Raw File.

In Vuescan, Custom resolution setting (in the Input Tab) will behave
properly. It's expecting the dpi to be equiv. to the scan ppi. On the
other hand, I wouldn't touch Vuescan's downsample with a ten foot barge
pole. It's results are inferior to Photoshop's bicubic.

Anyway, you can edit the file I mentioned. Or just fix the dpi setting
with an action it PS.

 

[Andreas]

Mendel, thank you for the tip, but in my case the folder "Program
Files\DS_Dual2\Job\Custom" is empty -never mind!

 

[Andreas]

Thank you both -I made a scan with the Minolta-software today and yes,
what you say seems to be right: it's the input resolution that matters,
not the reported output resolution. Strange that I did not notice this
before, I did not do the counting.

Apart from this, the Minolta-software gives (at first sight) better
scans than e.g. Vuescan does (colors and brightness are +/- OK) but here
also there is much clipping. A known "feature" of the Minolta-software,
as I learned during past years.

 

[Mendel Leisk]

I think you need to save the resolution parameters, to get a file for
editting. You click one of the two icons in the upper corner of that
area, and give it a name. THEN, that file name should appear in your
folder, and you can edit the output resolution, I think.

Do save a copy first, just in case, but I think it's pretty
straightforward.

 

[JJackson382]

I intensely dislike scanner (or any!) software which is "bossy" but to
prevent you from even scanning at the native resolution of the scanner
would be a new low!! Anyway, I see others more familiar with Minolta
software have already posted the solution.

In the case of the Minolta 5400, the sw is NOT "bossy" and WON'T prevent
an user from scanning at the native resolution of 5400dpi. But the user
needs to set the "Input dpi" to 5400 (or whatever other desired
resolution), and simply ignore the "Output dpi" resolution number.

 

[JJackson382]

The one advantage I see of haveing the output dpi of Elite 5400 (for
example) set to 5400, is if you're outputting 16bit linear for use as
Vuescan Raw File.

In Vuescan, Custom resolution setting (in the Input Tab) will behave
properly. It's expecting the dpi to be equiv. to the scan ppi. On the
other hand, I wouldn't touch Vuescan's downsample with a ten foot barge
pole. It's results are inferior to Photoshop's bicubic.

Anyway, you can edit the file I mentioned. Or just fix the dpi setting
with an action it PS.

If you cannot substantiate how editing the file you referred to changes
a scan file's pixel counts in PS' Image Size, you should stop creating
yet another urban legend.

 

[Mendel Leisk]

I think we are getting off on the wrong foot here. The object was to
set the dpi (not the ppi) to a value higher than the Minolta Scan
Utility allows within the interface. With my Elite 5400, the ceiling is
4000dpi. Editting the dpi line in this file makes NO change to the
pixel count, but it does allow you to set the dpi of the file to 5400,
or whatever you type in, if you wish.

So how am I creating an "urban legend" by sharing this? It works. You
can use it if you like, or not.

 

[JJackson382]

I think we are getting off on the wrong foot here. The object was to
set the dpi (not the ppi) to a value higher than the Minolta Scan
Utility allows within the interface. With my Elite 5400, the ceiling is
4000dpi. Editting the dpi line in this file makes NO change to the
pixel count, but it does allow you to set the dpi of the file to 5400,
or whatever you type in, if you wish.

So how am I creating an "urban legend" by sharing this? It works. You
can use it if you like, or not.

Andreas' original comment was:

"Surprise: the Minolta-software for my scanner (a Scan Dual II, USB) is
not able to deliver scans in the native resolution of the scanner, 2820
dpi."

The implication (and another urban legend) was that the Minoltas do not
produce a scan file with the native and claimed maximum resolution. The
misleading "Output dpi" of 4000 leads users to think that the 5400's
scan files are at 4000dpi even if the "Input dpi" is set to 5400.
Kennedy's and my comments were trying to dispel this by explaining how
to look at Image Size' pixel counts to verify what a scan file'
resolution really is, and to ignore the "Output dpi" value. It does take
some fundamental understanding of resolution and how to use Image Size,
but it does not require editing any files.

Your comments not only supported the original urban legend, but
introduce another one on how to "fix" a "problem" that does not need
fixing.

We come here for Q&As not found in the manuals, etc., and do not need to
be confused further.

 

[Mendel Leisk]

I'm just attempting to set dpi, which you, I and I think 99% of the
folks here know to be just a printing parameter. No suprises, I
thought. This can be set in Photoshop, after the scan, as well. I know
it has nothing to do with the pixel dimensions.

The file is there, IF you've save a "job" in MSU. Editting it to change
PPI works, I do it. If you want to be self appointed squelcher of
whatever you recognize to be "urban legend", carry on.

 

[JJackson382]

I'm just attempting to set dpi, which you, I and I think 99% of the
folks here know to be just a printing parameter. No suprises, I
thought. This can be set in Photoshop, after the scan, as well. I know
it has nothing to do with the pixel dimensions.

The file is there, IF you've save a "job" in MSU. Editting it to change
PPI works, I do it. If you want to be self appointed squelcher of
whatever you recognize to be "urban legend", carry on.

Every poster who posts substantiated information and suggestions with
context is a squelcher of "urban legend". We just need more of them to
keep legend spreaders away from this ng.

 

[Andreas]

Cool down! JJ you were right about the output resolution (thanks) but I
just as much appreciated that ML was very willing to help (thanks).

Andreas.

 

[Chris Cox]

You're probably familiar with these but here goes anyway (a random
sample off the top of my head and in no particular order):

http://www.aim-dtp.net/ - sometimes controversial site but lots of
stuff including:
http://www.aim-dtp.net/aim/download/gamma_maps.zip AMP gamma files for
Photoshop

Actually, that's a misinformation web site belonging to a well known
usenet troll.
Don't go there.

Chris

 

[Don]

Actually, that's a misinformation web site belonging to a well known
usenet troll.
Don't go there.

Thereby confirming what I said above that it's a "sometimes
controversial site". ;o)

All I can say is that I (for one) definitely favored those AMP files
until I wrote my own gamma conversion using 16-bit LUTs as a part of
my scanner program. However, I don't edit in linear gamma.

Having said that, I'm staying out of this one... ;o)

Don.