Hi all,
I've been playing with HDR stuff in Photoshop during the past couple
of days.
The Merge to HDR tool was obviously designed for digital cameras, but
I've been abusing it a bit by throwing it a handful of files from my
film scanner to see if I can obtain improved shadow detail.
Basically I scanned the same frame a few times with different
exposure settings then fed them into the HDR tool.
In the end I've decided that it's capable of some fantastic results
but unfortunately its limitations mean it's not really useful to me.
When importing files there is an option to have it automatically
align the images. This is great as my scanner doesn't seem to scan
in exactly the same place each time. The problem is that it runs out
of memory with two 180Mb files (on a 3Gb machine). Using 50Mb files
worked fine, and the results didn't need a lot of massaging
afterwards to produce an excellent result. With just two files I was
able to get about an extra stop of shadow detail.
Converting HDR down to 16-bit is quite a complicated task in
itself... I wouldn't be surprised if someone had written a book on
just that subject. It needed to be done because I wanted to apply
some Curves layers, but you can't use layers in HDR mode (in fact,
you can't do much at all in HDR mode).
With my large files I tried merging the shadow areas manually but it
required quite a lot of effort to achieve a result that wasn't quite
as good. It might be worth doing for a critical image but not for
the scans I'm doing at the moment.
I might have another go at it by attempting to manually align the
images before feeding them into the HDR tool. Hopefully it won't be
too frustrating :)
- Dave
