Re: HDR program

I tried manually blending two scans to extend the dynamic range in PS,
and quickly gave up. Aligning the two layers precisely is darn near
impossible. In some cases masking out portions in one layer by painting
can be a pain. Last but not least, creating a natural looking blend may
take several trial and error scans with different exposures. If HDR can
do these automatically or with ease, I want to learn about it. Where can
I find an intro tutorial? Thanks.

Don wrote:
>
> On 2 Aug 2005 10:00:12 -0700, "Roger S." <rsmith02@xxxxxxxxx> wrote:
>
> >I'm only interested in exposure blending and Photomatix does this well.
>
> Well, "exposure blending" is *conceptually* really a poor man's HDR
> with a series of only 2 images. Any proper HDR program can "blend"
> only two images with its eyes closed... ;o)
>
> > 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.
>
> That's very common with multi-pass multi-scanning (i.e. when the
> scanner does one image and then goes back and scans another). Some
> scanners are better at it than others but there is bound to be some
> misalignment. What's more it's not in the nice full pixel chunks but
> in sub-pixels fragments!
>
> That's why aligning images before blending is essential! Personally,
> this alignment has caused me grief to no end (in the past)! :-(
>
> The frustrating thing is that every scanner is capable of single-pass
> multi-scanning but the manufacturers intentionally "disable" this!
> Darn marketroids! It's perfectly feasible to have the scanner perform
> two (or more!) exposures per line and "blend" them all before output
> thereby resulting in a scanner with a virtually unlimited dynamic
> range!! Even the darkest Kodachromes would be powerless against that!
>
> >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...).
>
> When the images are *not* the same size most programs don't go through
> the trouble of aligning them. The reason it looks like mush is because
> by changing the size you've moved the image and then the two are (even
> more?) misaligned!
>
> As to HDR Shop, you must be doing something terribly wrong to have all
> these problems. It's a very solid program. My main beef was the 8-bit
> input but considering it was written as a demonstration for a
> scientific paper about 10 years ago - it's pretty amazing!
>
> If you post images and/or specifics maybe we can locate why you're
> having problems.
>
> Don.
.

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