Maximising tonal range using multiple files and Load Files into Photoshop Layers

[Dinarius]

I've been playing with maximising dynamic range when processing more than one exposure of the same scene.

I've also been playing with treating the one file (which has good highlight detail) in three different ways in ACR, then saving out all three versions as Smart Objects.

In short, I'm confused......

I want to get a greater dynamic range without using HDR software and without using CS5's HDR option.

If I adjust three files and then use Load Files into Photoshop Layers, I get a merged file in which the darkest image is what I see. If I highlight this layer and and the middle layer and then play with both Opacity and Fill, I can get a result that is quite acceptable. (If I adjust Opacity and Fill for the brightest layer, it pixelates)

All in all a pretty good result if I have done as much as possible in ACR (colour balance, exposure, recovery, blacks, in particular) beforehand.

I get a result that doesn't produce ghosting - all very well in funky HDR, but if your's shooting interiors with bright windows visible, an absolute no-no.

What I'm wondering is.....

a. Is this the best approach? If so, any suggestions (or links to suggestions) as to how I can improve on it?

b. If not, what should I be doing?

Thanks,

D.

ps. One final observation....If, instead, I use Photomerge in Bridge to merge the three files to CS5, it opens showing the brightest layer on top. Adjusting Opacity/Fill on this layer again causes pixelation, while adjusting the other two layers has no effect at all. Obviously a reason for this.

[dmerger]

You may want to try using the "blend if" sliders to blend the different layers. Make sure the blends are very gradual so that you get a seamless blend.  With this method, you can easily target which portions of each layer you want to use.  http://members.ozemail.com.au/~binaryfx/blendif.html

Tony Kuyper’s Luminosity Masks are another similar option.

[Dinarius]

Just discovered an answer to this question on page 364 of Martin Evening's 'Adobe Photoshop CS4 For Photographers'. A piece called 'Multiple Raw Conversions' deals with processing a single file using Smart Objects. Of, this assumes that the single file has something in the shadows AND the highlights to edit.

D.

[RFPhotography]

There are many ways to blend multiple images to achieve a result.  Layer blending modes, opacity/fill, luminance masks.  All work well.  If you have the Extended version of PS you can load multiple files, convert the stack to a Smart Object and use the Mean or Median stack mode as well as a starting point.  You can also use HDR Pro without going into the tonemap controls.  Merge to 32 bit, go to View>32 bit preview options.  Adjust Exposure & Gamma to bring your highlights under control, make further adjustments to the 32 bit file with the Levels and H/S.  Go to Image>Mode>16 bit, select Exposure & Gamma from the dropdown menu in the tonemap screen which will drop the image to 16 bit without using the HDR tonemapping controls then edit further using the regular editing tools. 

If you're using the Layer Style options and the Blend If sliders, you can make the transitions smoother by separating the sliders.  Holding the Alt key in Windows (I don't know what the equivalent is on a Mac, don't really care either) and clicking on the slider will separate it into two pieces and allow you to make more refined transitions to the layer blending.

Making multiple edits of a single raw file won't; however, really give you extended dynamic range.  You're simply pushing around what exists in that single file and are still limited by any highlight or shadow clipping that may be in the file as you point out.  To truly take advantage of options for extending dynamic range you need to make multiple exposures at the time of shooting.

[Dinarius]

Bob, thanks for the reply.

The problem I frequently have with HDR in CS5 is "ghosting" - if I'm using the term correctly. What I mean is this: imagine a spot light illuminating a white wall in the image. When I merge three images to HDR, I sometimes get the pool of light on the wall exhibiting an 'oil on water' look. i.e. the pool of light is broken into bands, not all of the same density & sometimes not all the same colour either.

How can I avoid/ deal with this?

Thanks.

D.

[RFPhotography]

Yep, I know what you mean.  That's a possibility anytime you use multiple exposures to blend.  If there are moving elements within the frame then you'll get ghosting.  What you're talking about isn't really ghosting though.  Sounds like you're almost talking about a posterization type of effect.  I understand that too.  It should go away if you zoom in to 100%.

[cidrmakr]

I've played with it quite a bit and have found that the only good solution is photomatix pro.  cs5 hdr really sucks when compared.  The key is that photomatix ignores any acr adjustments (that are in the xmp file anyway) so you have to be very careful to get enough good exposures with the raw files to have detail in the full range - i've used as many as 8.  To view those files in bridge you can't see detail or range in the dark images but when you load them the detail becomes apparent.  It blends them seamlessly and can produce an image that is real with no hdr "effects" if you choose to do so.  From there as a 16 bit tiff to ps.  I've successfully blended shots from 1/ 250 @ f11 to 2 sec at f11.  (Aperture/manual mode and manual focus is necessary.)

[RFPhotography]

If you want adjustments to the raw files to be taken into account by PM, output to 16 bit TIFF and load those TIFF files into PM.  The raw converter in PM isn't that good so loading TIFFs is the better option anyway.  The folks at HDRSoft acknowledge this as well.

HDR Pro is a fine application.  It works a bit differently from PM and takes a bit of getting used to but it can produce stellar results.

[Dinarius]

Bob,

A few more comments.....

1. I'm not sure what you mean by, "You can also use HDR Pro without going into the tonemap controls.  Merge to 32 bit, go to View>32 bit preview options.  Adjust Exposure & Gamma to bring your highlights under control, make further adjustments to the 32 bit file with the Levels and H/S."

I'm using CS5. In Bridge, I choose Tools/Photoshop/Merge to HDR Pro. I can then choose the 32bit optiion from the dropdown menu and make the Set White Point Preview adjustment. But, that's all.

I'm not sure how I can access, View/32 bit preview options. It's always greyed out.

2. In 16bit mode, as with ACR, I'm finding that adjusting Exposure first is best, followed by Highlight and Gamma, with a bit of back and forth between them.

I find that contrast is best done back in PS and not using the Curve in HDR.

Annoying that there is no 0-255 or % readout within HDR to tell you how you highlights (in particular) and shadows are behaving. A bit odd for a so-called HDR program, no?

Have to say that, with the file I've been playing with (an interior of a gallery, no windows, some over head lighting and one large flood light pointing at a wall, which appears in the shot), opening the three exposures using Bridge/Tools/Load Files into Photoshop layers... and then playing with the darkest and the middle layers, gives me the best result. Being able to separate Levels/Curves layers for these lower layers is hugely flexible. I can open up the bottom layer first and set the brightness of the flood light on the wall and then go from there. Also, the pool of light on the wall is clean as a whistle! I can't get it this clean in HDR.

Thanks again.

D.

[RFPhotography]

You're using the Standard version of PS, yes?  Sorry, I should have asked that before.  The 32 bit preview is only available in the Extended version.  You can do the same thing with the Standard version though, just a bit differently and it sounds like you're doing it already.  When you go into the HDR Tonemap function, select Exposure and Gamma from the dropdown then after adjusting those, click OK.  The biggest difference is that in the Extended version, with the 32 bit preview you can make Exposure/Gamma changes and then use other available editing tools like Levels and H/S in 32 bit mode. 

The regular histogram in PS doesn't work properly with 32 bit images.  Even the one in the Local Adaptation tonemap control isn't that good because it's not live.  That's one aspect of HDR Pro that needs improvement. 

[Dinarius]

Bob,

You're right, I'm using the standard version.

Slightly off topic, but I have two different pics stacked on one another. What's the best way to make an adjustement (e.g. Levels) to the upper one, without affecting the lower one? Masking it?

Thanks.

D.

[Sheldon N]

Bob,

You're right, I'm using the standard version.

Slightly off topic, but I have two different pics stacked on one another. What's the best way to make an adjustement (e.g. Levels) to the upper one, without affecting the lower one? Masking it?

Thanks.

D.

Use an adjustment layer with a clipping mask. Put the adjustment layer on top of the layer you want to adjust, then click the icon that looks like two overlapping circles. This will limit the affect of the adjustment layer to just the image layer that you clipped it to.  A VERY handy feature.

Regarding exposure blending, one thing I've found to work well is simple hand blending using a Pen tablet, layer masks and low opacity/flow brushes. It can be tedious work, but will often produce a more natural looking result.