Why HDRs don’t look real  

Let’s start out by saying; you may not want your HDRs to look real, maybe that’s not your Artistic intent or vision. Or maybe you don’t even know what your artist intent or vision is and maybe you are just following what others do. And that’s OK, It all depends what you want out of something. But perhaps, if you want to take images beyond snapshots and work on Art you may want to delve into what your vision is. 

But on the pretense that you want your images to look real and natural, what is it that makes so many HDR images not look real at all? 

The quick answers is: lack of shadow. 

To understand this better we need to delve into the world of art and painting/drawing. It’s kind of ironic that if we want to find realism in our photographs we look to Painters. But the truth is a Photograph is no more real than a painting and it is the artist that takes it to where he/she wants it to be in the style he prefers to work in. 

 If your intent in painting is to have a Realism style to your Painting/Drawings then you follow the same path that needs to be taken in Photography. The things that take you where your intent goes are:

• Color/Tone
• Composition
• Perspective
• Shadow 

Ah Shadow. Why is shadow important? Shadow brings depth, shape and texture to an image, whether it is a painting or a photograph. 

If we were painting a still life of a bowl of fruit, as often is a beginning lesson for the art student, if it was a bowl of lemons and we just drew oblong objects and painted them yellow, would they look realistic? No not at all, they would look flat and have no shape whatsoever.

 By adding shadow, we can make that flat oblong object and make it look round, 3 dimensional and globe like. 

Also by the use of shadow in our painting we could make the skin of the lemon appear to have texture as we add shadow to all the dimples in the skin of the lemon. Plain yellow the same tone will never look like a real lemon. And painting small black dots won’t do it either. In fact, those dimples in the lemon are the same color as the rest of the lemon, but shadow makes them appear different to our eyes and also makes us use a different shade of paint to represent them in a painting.

How did we get here?

How did we get so unreal looking in our HDRs. Well somewhere along the way we were led into believing that we need to “Bring tones up out of the Shadows” To have “Detail in all Areas”. which of course has some truth to it. We are trying to see, in our HDR photographs, as our eyes do and because of our eye’s extended dynamic range, we are able to see detail in shadows that can get lost in a normal photograph. We also have to keep in mind. that we now have to fit this wide dynamic range into a Standard dynamic range medium (LCD Screen/Print). 

But somewhere along the way, the way was lost. We brought up the shadows so far that we now created what I refer to as a Mono-Luminance image. Yes we have different hues but we even things out so far that every hue has the same luminance level and we now created a SUPER LOW DYNAMIC RANGE IMAGE, not only that but in seeking more detail in the shadows we eliminated the detail because we LOST the shadows! The very thing that defines shape and texture and full range of Hue, Shade and Tone. 

 So a little further down the road after this first wave of nonsense was over, someone determined that, “Ah I see what’s wrong, there is no shadow information, there is no black point. So they turned to the controls that are listed as: “Shadow” or “Black” and they began to jack up those controls. But in doing that they created what I call “Dirty” HDRs. They look dirty and smudged like someone working in the coal mine just handled all your images. 

 So, if shadows are what’s missing, why didn’t increasing the shadow or black  fix it? Simply because…shadows aren’t black. They can be but in most cases – far more cases- Shadows are not black. 

Returning to our painting

if we wanted to represent a shadow in our painting, we wouldn’t use black. We might use a darker shade of the same hue, or we could even use a complimentary color to represent the shadow and in varying degrees to get the full gradient of that shadow. And there may eventually be some black or maybe there never would be. 

If I was painting a picture of a shadow on white fence, would I use Black? No, I would most likely use a light shade of gray; in fact that shade of gray could be so light that it would be considered a highlight in our histogram. So why when adjusting our photograph would increasing the “Shadows” adjustment change or bring back our TRUE shadow? Of course the answer is; it wouldn’t

 If we look at the histogram for this image we see that there isn’t even any information in the shadows part of the histogram, even though of course the image has shadow

 Confusion of Terms

This comes from a confusion of terms; we use the same word to describe two different things, In Photography we use Shadow, Midtone and Highlight to describe the spectrum of tones from Dark to Light or “Zones” But just because something has a shadow, does not mean that that shadow falls within the zone of a Shadow tone

 We can see that if we increase the “Shadows” slider on our Levels adjustment it has no real effect on the Shadow and once again it just dirties up the image. Adjusting the midtones would affect the shadow since that is the range in which they occur.

 And if we look at the effects of over-tone compression (Mono-Luminance) we see, the shadow gets faint and we lose the texture in the wood fence, all making the image look less real and flat

The Cure – It’s all about Contrast 

HDR processing involves lowering Contrast, compressing say a contrast ratio of 100,000:1 to 1,000:1.But it does not mean eliminating it, it means we have FULL contrast for our medium 

So how do we fix all this? First off, get off to a good start. Don’t use a lot of the controls that get you in trouble in the first place. If you use Nik HDR Efex Pro 2, don’t use a lot of compression. The more we compress the tonal range, the more true shadows get lost. We need enough compression to fit that wide dynamic range of our multiple exposures down to what is viewable in our final medium, but that’s it. Don’t use any more than that. If you are using Photomatix Pro, watch out how much strength and lighting adjustment you use, these two controls take care of compression also. Even if you simply use Lightroom or ACR, watch how much Fill and Recovery or White and Shadow as it is called in LR4 (There’s that word again) 

So once we have better control from the start we can also bring back true shadows in post or using other controls in our HDR programs. We can increase the true shadows by increasing contrast of our shades or tones. We can use the Gamma control in Photomatix, or when using Levels in Photoshop, the center control for Midtones is also known as the Gamma Control and also can increase contrast in the areas we need and not just the “Shadow” areas (Zones 0 – 3 if you follow the zone system). With Curves adjustment we can increase contrast throughout the image with something as simple as an S-curve. A Good Gamma adjustment can eliminate the “Fog” that ia a part of so many images I see.

If you’ve ever wondered how the Hyper real effects work, they work on the same thing but at a different level, they make Micro-Contrast adjustments to all tones. This is the effects you see when using Nik’s Structure control, Lightroom’s Clarity or Topaz Adjust and Lucasart Plug- ins. In fact if we just change a few things, it’s how sharpening works too…but enough 

Now if you like the current state of the art…well, that’s fine it is your art. But if you are wondering why people say it doesn’t look real…look in the shadows…the REAL Shadows 

Oh and if you want my interpretation of the “Real” HDR, here is the same image we started with, with real sensible adjustments and …shadows. Shadows throughout the entire tonal range

 Hope that Helps,

PT