Histograms: VueScan vs Photoshop 6

[Frank Kolwicz]

The histogram shown when I do a scan with VS looks considerably
different when the image file is opened in Photoshop, so much so that
sometimes I have to re-scan in order to have all the data I want from
the image. How can I get the two programs to see the same file data
the same way?

If you want to see a typical example, I have a superimposed VS
histogram on the one for the same image in Photoshop posted at
http://www.photoartsguild.org/web/tiki-browse_image.php?galleryId=
4&sort_mode=created_desc&desp=0&offset=0&imageId=353.

The solid black curve is the Photohsop histogram, the colored curves
are VS. As you can probably imagine, if I had scanned using a bit more
black- and whitepoint clipping, I could have lost some detail at the
ends and, in fact, that has happened at times.

Scan info: This happens to be from a B&W negative, but the same thing
occurs with other film, too; scanner is a ScanMulti Pro; VS 8.0.4
Professional Ed.; Photoshop 6.0.1; file saved as uncompressed TIF.

If I have to save as RAW to get what I want, please suggest a good
free or cheap RAW plugin for Photoshop 6.

Thanks for any help,

Frank

 

[Bart van der Wolf]

The histogram shown when I do a scan with VS looks
considerably different when the image file is opened in
Photoshop, so much so that sometimes I have to re-scan in
order to have all the data I want from the image. How can
I get the two programs to see the same file data the same
way?

The Photoshop histogram chops off the higher bin counts, thus allowing
more room to show the lower ones, whereas VueScan shows all. If you
want to have a better view of the lower count bins, switch the
"Prefs|Histogram type" to "Square root" or even better "Logarithmic".

You can also use "Color|Pixel colors" to get a visual warning for
clipping.

SNIP

If I have to save as RAW to get what I want, please suggest a good
free or cheap RAW plugin for Photoshop 6.

You don't need a Raw plugin, because the VueScan Raws are saved as
TIFFs. Photoshop has no problem reading them.

Bart

 

[Mendel Leisk]

The Photoshop histogram chops off the higher bin counts, thus allowing
more room to show the lower ones, whereas VueScan shows all. If you
want to have a better view of the lower count bins, switch the
"Prefs|Histogram type" to "Square root" or even better "Logarithmic".

You can also use "Color|Pixel colors" to get a visual warning for
clipping.

SNIP

You don't need a Raw plugin, because the VueScan Raws are saved as
TIFFs. Photoshop has no problem reading them.

Bart

Also, I think Vuescan's histogram excludes area defined in Crop|Buffer
setting, Typically 15% around the perimeter of the scan is excluded,
if you haven't changed this.

 

[Frank Kolwicz]

Thanks, Bart, that helps a lot.

A funny thing happened: after posting I went and upgraded to the
latest version of VS and now my linear histograms are exactly alike!
All previous versions of VS and PS had different linear histos, but
not any more.

Frank

 

[Don]

A funny thing happened: after posting I went and upgraded to the
latest version of VS and now my linear histograms are exactly alike!
All previous versions of VS and PS had different linear histos, but
not any more.

That's probably because by upgrading you must have reset some setting.


VueScan is notorious for its unwieldy "user interface" so you probably
got caught by some arcane interaction between various (often seemingly
unrelated) options.

On the other hand, it might have been just another VueScan bug. If you
wait a while it's bound come around again - like a bus.. ;o)

Don.