HDR program

[Roger S.]

In the spirit of the Twin Scan posts about combining scans for
increased dynamic range I just downloaded the trial of Photomatix:
http://www.hdrsoft.com/index.html

I took a particularly challenging slide, scanned it in Vuescan at exp 2
(for highlights) and exp 11 (for shadows). This program lets you
either go the HDR route and tonemap back to a 16 bit tiff or just
combine files directly. The results I got just combining them were
better than anything I had gotten with curves and masks and this method
seems quite viable. Alignment and sharpness was fine and the
highlights were preserved even though the second scan was badly
clipped. This is much better than the results I got with hdrshop.

I'd be curious to hear other people's experiences or tips for using
this with Vuescan.

 

[Bart van der Wolf]

In the spirit of the Twin Scan posts about combining scans
for increased dynamic range I just downloaded the trial of
Photomatix:
http://www.hdrsoft.com/index.html
SNIP
I'd be curious to hear other people's experiences or tips for
using this with Vuescan.

Yes, that should work reasonably well (after alignment). You might
also consider an intermediate exposure, and see if that helps for your
particular image.

The HDR tonemapping of Photomatix leaves something to be desired
(non-monotone gradients produce visibly darkened e.g. skies or other
large highlights), but if you stick to 'combining' (Exposure blending)
the images, things look more natural (an S-shaped 'curves' correction
will help).

Bart

 

[Don]

In the spirit of the Twin Scan posts about combining scans for
increased dynamic range I just downloaded the trial of Photomatix:
http://www.hdrsoft.com/index.html

Actually, that's not a very good program. You may want to try again:

http://www.ict.usc.edu/graphics/HDRShop/

It's fully functional and free. Also, it will automatically align the
images! It does have its problems (e.g. 8-bit input only) but you can
set up an external program to edit each "exposure" before combining.

Speaking of which, to combine the images HDRShop has a free tone
mapping plugin called "Reinhard HDR Tonemapping Plugin" the link to
which is at the site:
http://www.ict.usc.edu/graphics/HDRShop/.

I wrote several messages about all this a couple of months ago so
check the archives. In the meantime here's a few more quotes:

I came across a few stand-alone tone mapping alternatives such as:
http://scanline.ca/exrtools/ and
http://www.mpi-sb.mpg.de/resources/pfstools/
but they all run on Linux, probably because initial work on all this
was done on Unix workstations.

Even though the original HDR algorithm (combining of different
exposures) goes back to 1998, tone mapping is still quite new and
there are many different ways of doing it, all vying for dominance. A
nice comparison can be found here:
http://www.cgg.cvut.cz/~cadikm/tmo/

There's another free HDR generating program at www.acm.uiuc.edu called
"HDRIE" but it's quite buggy and export doesn't work. But before it
can run at all, a huge 10 MB library must be downloaded.

This is much better than the results I got with hdrshop.

That's interesting because Photomatix is generally considered
inferior. Also, the absence of auto-alignment is quite a problem (but
you have to magnify to notice). In general, Photomatix is considered
pretty bad even when compared to HDRShop so it's a bit surprising you
found it better. But, if it works for you...

I'd be curious to hear other people's experiences or tips for using
this with Vuescan.

It's the good old GIGO (garbage-in garbage-out)... ;o)

Seriously though, the source of the images is really not that
important. Unless, of course, the images are severely corrupt (for
whatever reasons e.g. shaky camera shots instead of using a tripod).

Don.

 

[Hecate]

Actually, that's not a very good program. You may want to try again:

I looked at that site and I thought the examples they showed were,
frankly unnatural. The end images didn't look real because the shadows
didn't obey the lighting direction.

http://www.ict.usc.edu/graphics/HDRShop/

It's fully functional and free. Also, it will automatically align the
images! It does have its problems (e.g. 8-bit input only) but you can
set up an external program to edit each "exposure" before combining.

Speaking of which, to combine the images HDRShop has a free tone
mapping plugin called "Reinhard HDR Tonemapping Plugin" the link to
which is at the site:
http://www.ict.usc.edu/graphics/HDRShop/.

I wrote several messages about all this a couple of months ago so
check the archives. In the meantime here's a few more quotes:

I came across a few stand-alone tone mapping alternatives such as:
http://scanline.ca/exrtools/ and
http://www.mpi-sb.mpg.de/resources/pfstools/
but they all run on Linux, probably because initial work on all this
was done on Unix workstations.

Even though the original HDR algorithm (combining of different
exposures) goes back to 1998, tone mapping is still quite new and
there are many different ways of doing it, all vying for dominance. A
nice comparison can be found here:
http://www.cgg.cvut.cz/~cadikm/tmo/

There's another free HDR generating program at www.acm.uiuc.edu called
"HDRIE" but it's quite buggy and export doesn't work. But before it
can run at all, a huge 10 MB library must be downloaded.


That's interesting because Photomatix is generally considered
inferior. Also, the absence of auto-alignment is quite a problem (but
you have to magnify to notice). In general, Photomatix is considered
pretty bad even when compared to HDRShop so it's a bit surprising you
found it better. But, if it works for you...

I'm keeping this post and I'll try your suggestion.

Thanks,

--

Hecate - The Real One
(e-mail address removed)
Fashion: Buying things you don't need, with money
you don't have, to impress people you don't like...

 

[Bart van der Wolf]

SNIP

Generally? All of the program's functionality, or just the
tonemapping?

Photomatix offers several alignment options, amongst which an
automatic one.

Again, broad sweeping statements aside, considered pretty bad by whom?

HDRShop doesn't allow to do exposure blending (other than with image
math), it constructs an HDR image out of multiple LDR images. Blending
is a totally different technique than HDR construction/tonemapping.

I'm keeping this post and I'll try your suggestion.

In that case just remember that HDRShop in my experience doesn't
auto-align :-( but Photomatix does . Also the Reinhard tonemapping
plugin for HDRShop can cause weird highlight colors, but then (HDR)
tonemapping is often more art than science (although the better
approaches are certainly based on solid science).

Bart

 

[Roger S.]

I'm only interested in exposure blending and Photomatix does this well.
However when I tried doing this on 4000dpi scans I had problems
because Vuescan and my scanner aren't completely consistent and are
sometimes a pixel short in one dimension.

Photomatix rejects these scans and I'm not sure what to do about this.
I tried resizing in Photoshop but the resulting blend looked like mush
up close (still better than HDR Shop's mush with color fringing...).

Should I convert to 8-bit and try a trim in photoshop 7 instead or are
there better ways to deal with this? On a slide where the two scans
happened to be the same dimensions Photomatix did quite well with its
simple combine 2 images feature.

 

[Don]

I looked at that site and I thought the examples they showed were,
frankly unnatural. The end images didn't look real because the shadows
didn't obey the lighting direction.

The whole thing just looks a bit fishy, doesn't it? For me, the fact
that they force you align images manually was a dead giveaway (proper
HDR programs do that as a part of the merge algorithm). And then when
on top of all that it started crashing on me, I just gave it the boot.

But I'm not surprised that a Vuescan user finds it good! They just
seem to have this unnatural attachment to bad programs that crash! ;o)

I'm keeping this post and I'll try your suggestion.

Thanks,

Glad to be of help!

Don.

 

[Bart van der Wolf]

I'm only interested in exposure blending and Photomatix does this
well. However when I tried doing this on 4000dpi scans I had
problems because Vuescan and my scanner aren't completely
consistent and are sometimes a pixel short in one dimension.

VueScan doesn't align the individual exposures. It could with this:
<http://www.anyhere.com/gward/papers/jgtpap2.pdf>
as a backgrounder (actually quite simple once you grasp the underlying
principle).

Photomatix rejects these scans and I'm not sure what to do about
this.

I've yet to experience that. The authors may be interested in the
conditions that cause that to happen.
SNIP

Bart

 

[Roger S.]

HDRsoft crashes on me and refuses to deal with large images (4000dpi
scans). The program may not be designed to overcome RAM issues- I can
open several 4000dpi scans in Photoshop without a problem. It doesn't
seem to align images at all with some serious ghosting/blurring issues.
Photomatix has blurring issues with the same input scans but looks
much better. Neither has a problem with perfectly aligned scans.
Vuescan's long exposure pass only suffers from slight blurring
sometimes, but doesn't match the original slide as well as Photomatix
does with combined exposures (VS is still too dark and undersaturated.)

Bart, I'll try contacting the authors about this. If a scan is 1 pixel
off in one dimension the program says size mismatch and refuses to run
in batch or normal mode.

 

[Bart van der Wolf]

HDRsoft crashes on me and refuses to deal with large images
(4000dpi scans). The program may not be designed to overcome
RAM issues- I can open several 4000dpi scans in Photoshop
without a problem.

FWIW, I've tried Photomatix Pro with a series of 4992x3328 px
8-bit/channel JPEG images, which it can handle just fine. I have
experienced some problems with handling 16-bit versions in the past,
but that was with an earlier version (they're at version 2.1 now). I
contributed the earlier issues to lack of memory on the PC that I
used, but it might also be a memory management issue that needs
ironing out. I have yet to try the newer version again with 16-bit
files.

HDRShop (version 1.03) does fine with the above mentioned
(pre-)aligned JPEGs.

It doesn't seem to align images at all with some serious
ghosting/blurring issues.

That's my observation as well.

Photomatix has blurring issues with the same input scans but looks
much better. Neither has a problem with perfectly aligned scans.

Photomatix has several methods for alignment, so maybe some human
intervention with the more elaborate methods will help.

Vuescan's long exposure pass only suffers from slight
blurring sometimes, but doesn't match the original slide
as well as Photomatix does with combined exposures
(VS is still too dark and undersaturated.)

VueScan doesn't do alignment at all, so it depends on the mechanical
accuracy of the scanner and the dimensional stability of the image
carrier. Had the author gone in the direction of adding support for
HDR image creation from multiple LDR images then he could have also
served a larger audience, namely digicam users (VS reads Raw files
from most digicams, and can read JPEGs and TIFFs as input). Since
alignment functionality would be inescapable for that, he'd have
solved some of the issues of the Long Exposure function as well
(alignment and response curve determination).

Bart, I'll try contacting the authors about this. If a scan is 1
pixel
off in one dimension the program says size mismatch and refuses to
run
in batch or normal mode.

Assuming all images have the same pixel dimensions, that does sound
like a bug to me.

Bart