Monday, September 27, 2010

HDR Toning

If you are into photography, you would knew by now that HDR photography is all the rage for a while.

Google Search return a whopping 124,000,000 results on "HDR"!

HDR of course, stand for High Dynamic Range.

According to Wikipedia:

"High dynamic range imaging (HDRI or just HDR) is a set of techniques that allow a greater dynamic range of luminance between the lightest and darkest areas of an image than standard digital imaging techniques or photographic methods. This wider dynamic range allows HDR images to more accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to faint starlight."

Quite a mouth full? ;)

To the photographers, HDR photography is simply by taking shots of the same scene with different exposure and with the help of special software; recombining those shots together to form the final image with a WIDE dynamic range.

Without knowing, I; like thousands of photographers in the 60's were doing HDR like processes in the darkroom! I am talking about the "dodging" and "burning" under the enlarger to deliver more dynamic range to our print!

In 1994 while I was working in Singapore. I was asked to get a shot of the Singapore City Hall's new million dollars "light up" for the front page. I got the shot from a room at the Mandarin Hotel. As expected the City Hall was very over bright and the night skyline was under exposed.

There I was looking at my "shot" negative with my boss breathing down my neck screaming for front page picture! I had less than 90 minutes!

Four months before this I had set up my Mac workstation with a Kodak RFS3520 scanner and Photoshop 5.0.... this is where thinking outside the square scored! I muttered to myself, "why don't I do 4 scans and each scan optimising for different part of the scenes, I will then "cut" the parts and paste them together for a "balance exposure" shot?"

So "Double Scans" was born and I kept my Picture Editor job. The picture also won me an internal award for the best news picture of the month. Not knowing, I was creating some sort of HDR image :)

Another shot I like which I used similar technique was "Sky Fire".

This shot was a combination of two scans of the SAME negative, see below.

Then in 2005, Adobe; in Photoshop CS2 introduced the Merge to HDR function and photographers went crazy on the effect!

I remember Michael Reichmann of Luminous Landscape has this to say:

"In many ways, Photoshop CS2's HDR function is the holy grail of dynamic range. With properly shot and processed files it allows photographers to easily create images that were previously impossible, or at least very difficult to accomplish. But, good as it is, like a gun or nuclear power, it can be a force for evil as well as good.

Not every image needs to have 10-15 stops of dynamic range. In fact, most photographs look quite nice, thank you very much, with the 5-7 stops of dynamic range that we're used to. I fully expect to see some really silly if not downright ugly images in the months ahead, as photographers get their copies of Photoshop CS2 and start discovering what the HDR function is capable of.

But, as with all such tool [sic], in the hands of sensitive artists and competent craftsmen, I'm sure that we will start to be shown the world in new and exciting ways."

So like many photographers I feel the HDR photos all look a bit "strange" and never actually try it out, until...

I watch this one hour movie in Youtube:

Trey Ratcliff is a world famous HDR photographer and artist, in the one hour long presentation you are shown some of his best HDR work. And believe you me, they are absolutely STUNNING!

I also learn that with RAW image, I am able to create a HDR look alike; this function is available in Photoshop CS5 as HDR Toning!

To try out the effect, I choose this shot I took inside the St. Peter's Basilica in Rome.

You will notice the top left corner of the photo has not much detail and the detail INSIDE the dome are also blocked.

In Photoshop CS5 I opened this RAW image and at Image - Adjustment - HDR Toning, I create a HDR toning version of the image.

This is what the tone mapping image look like :)

Do you notice how the HDR toning brought back the detail on the top left and also inside the dome? On the negative side, the toning rendered the whole photo into a "painting like" look! Especially the people inside the picture, do they look a bit "weird" to you? ;) What can I do to make it look more photo realistic?

I went back to the original untouched image and proceed to "draw" a path around the arch in the photo, the path was then turn into a selection. I then save my selection.

After saving, I deselect the selection. See my the picture below for detail.

After I deselect the selection, I did a "select all", and copy then paste the image ON TOP of the HDR toned image. Now come the fun part...

I LOAD back the selection I saved and hit the "delete" key! Presto, this is what it look like!


By deleting the selected top part, I REVEAL the HDR part below. Notice the detail on the top left and the dome? Since the center area were NOT touch, they remain photo realistic.

Wait! There are more....

With the selection still active, I INVERT the selection.

Inverting the selection let me adjust the CENTER area, I did some LEVEL adjustment to darken and balance the center area to the outer area.

This is the final result, notice I also went and erase the inside left wall to reveal detail.

I think the process work! What is your opinion?

Here is a side by side, before and after comparison.

Famous Last Words:

HDR Toning, I really like what I see!

In a lot of way, the process is similar to the "Double Scan" technique that I pioneered in 1994!

More investigation will follow :)

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