Breaking up the HDR-processed image

We were in southern Greece in the middle of October and, one day, Sue and I found ourselves in an old Mycenaean tomb.  These are sometimes called 'tholos' or 'beehive' tombs; they're made of rock, domed, and covered with earth except for the entrance.  This particular tomb had fallen in centuries ago and nothing was left except the circular wall up to a height of about four feet and the entrance which had a gigantic lintel over it.  I pointed the camera upward and took a shot of the lintel but because the sky was overcast and bright the underside of the lintel was underexposed.  What to do?  I could see enough texture under the lintel so I supposed that HDR might retrieve something.  Here's the original:

Pretty grim.

I then proceeded to expose this mess to my HDR software.  I used Dynamic Photo HDR 4 and the settings were as follows: I chose 'Eye-catching' over 'Adaptive' and then selected 'Full HDR Process'. Once that was complete I chose the 'Auto Adaptive' tone-mapping process with the following parameters: Vivid Colors: 0.27, Light Radius: 4.1, Light Strength: 0.52. Other choices are possible.

 

I felt that I came out too bright but this is still usable. But I want to use the underside of the lintel separately from the rest of the picture.  The underside of the lintel is closer to what I really want but the rest has to be toned way down.  First I'm going to move the under side of the lintel and modify it by setting the opacity.  Then I'm going to use a different opacity for the rest of the picture.

First I used a mask to select just the underside of the lintel.  Here's a Photoshop screen shot.

Once it was a selection I then copied it and pasted it over the original.  It was way too bright there so I moved the opacity of the underside of the lintel down to 64%.  Here's the result.

Now the underside of the lintel is where it should be but the rest of the photograph could benefit by having the rest of the HDR-processed version layered over it.  I had saved the selection for the underside of the lintel.  I got that back and inversed it to select the rest of the picture without the lintel.  I then copied that and pasted it over the ongoing composite.  Here's a screen-shot of the result; it shows the composited lintel after opacity adjustment along with the rest of the  picture before opacity adjustment.  If you can make out the layer menu in this next shot you can see that the original is the bottom layer, the lintel (only) is the middle layer, and everything else in the HDR shot is the top layer.  Here it is at this stage:

Believe it or not this is  progress.  Yes the composite is garishly too bright but we're going to fix that by adjusting the opacity just for the part of the image that isn't the lintel underside.  I took the lower two layers (original and lintel underside) and merged them.  That leaves two layers.  The composite is on the bottom and the HDR shot minus the lintel is on the top layer.   Now simply adjust the opacity of this top layer down to 48%.  That leaves enough brightness so that details can be made out and it is appropriate to the lintel underside.  Here's what it looked like after I adjusted opacity.  Remember my goal in these sessions is clarity, not beauty.  Because I've been able to rescue the clarity this picture is now suitable for Squinchpix where you can see what I actually uploaded.

...and here's the original again so that you can compare:

The moral of the story is that you can cut up the product of any HDR transform any way you like and re-composite it back on the original with any adjustments you choose.

And because you've been such good students here is your reward:  This is a shot of the west coast of the Mani peninsula in southern Greece on a stormy day.  It was also processed with a modified HDR procedure.  You're looking south here towards Areopolis.

Until next time,

Bob