A Manifesto for my friends on HDRCreme

HDR is the most important development in photography since the discipline was invented.
That’s because photography and photographers have always lived with a dirty little secret; the brightness range reproducible by straight photographic techniques is laughably small. HDR has now expanded that by, let’s say, doubling the capturable brightness range.
And HDR is an idea about brightness.
It is not an idea about color. Color is lovely and because of that people always assume that color is more important in image-making (painting or photography) than it really is. But, compared to the importance of brightness in these disciplines, color is nothing. All painting and photography is a meditation about brightness. Nearly all changes in these disciplines involve a new way of thinking about how to render shadows.
HDR processing consists of two phases. In the first phase multiple pictures are mapped from a 12- or 14-bit capture space onto a 32-bit picture space. In the second phase the entire brightness range actually used in the 32-bit space is tone-mapped back onto a smaller space; one which is, perhaps, as wide as nine bits. This is done because no viewable medium can display more than nine bits of information (most display less). This is starting to change with certain (scarce) wide-range display devices but it doesn’t affect us yet. For us nine bits is still a hard parameter. If you want to see it then it has to fit into about nine bits of displayable space.
As I mentioned above people currently are mapping multiple images into 32-bit space in order to extend the brightness range. This is a time-honored technique and it is as old as photography itself. I honor those who are working in this area; they are getting amazing results and teaching us a great deal.
A case can also be made for single-image HDR. Multiple-image HDR is difficult to do right. It’s almost impossible to align multiple digital exposures correctly as a look at most multiple-image HDR photos will clearly show. Even one pixel off will degrade the picture. The insistence on multiple-image HDR must exclude certain important types of photography (sports, racing, nature photography, children, candids: anything with rapidly moving objects). More affirmatively I think that tone-mapping techniques have revealed to us just exactly what we’ve missed in our single images. Tone-mapping techniques have led to the potential rejuvenation of every photograph ever taken as long as we have it in its original form (RAW file, TIF file, photo negative, etc). Personally I was astounded to discover the actual brightness limitations I’d been living with over the years. Single-image HDR does have its challenges and I think there’s a lot of work to carefully define those challenges and how to overcome them. That is the purpose of my blog, sihdr.blogspot.com. None of this is intended to denigrate people working in multiple-image HDR. I recognize both the hard work and the astounding results. There’s room for everyone. People often use the term ‘pseudo-HDR’ when referring to single-image HDR. I, for one, think that we should eschew the use of this term. Why? Because it doesn’t aid the thinking process. There’s nothing phony or false about single-image HDR. It’s simply an HDR that skips the 32-bit space mapping function. Or if it is done then it is idempotent. With single-image HDR, in effect, we go straight to the tone-mapping phase. It’s just my personal hobby-horse but I know that the single-image HDR workers also have something to tell us.
Remember, though, that multiple-image HDR and single-image HDR are simply rapidly passing technological phases. But multiple-image HDR will pass first for the simple reason that there are billions more single images out there that would benefit from HDR processing (a business opportunity for someone). It’s inevitable that the camera manufacturers will support an HDR mode directly and they’re going to do it sooner rather than later. The ideal solution would be a sensor that captures, say, 16 brightness zones and a camera that incorporates it and which makes the number of desired capture zones user-selectable. Does anyone doubt that the next three years will produce such a camera? I don’t.
Extended brightness range is not the answer to every pictorial problem. Many photographs are taken expressly because much of the picture space is effectively blank through over-exposure or under-exposure. This is the modern photographic aesthetic and we should remember that HDR flies directly in its teeth.
HDR practitioners sometimes suppose that extended range is always desirable.
It isn’t.
To support the continuously articulated picture surface that HDR promises will require a new aesthetic. One that’s more characteristic of modern art (or art before the fifteenth century) than ‘photographic realism’. (There are good remarks about all this in Hockney’s Secret Knowledge, 2001). At the very least HDR (in whatever form it comes) will force us to re-learn that every picture is an artifact; a completely artificial creation. For example, there’s a photograph on HDRCreme of the Spanish town Ronda (http://hdrcreme.com/photos/3236-Ronda-Panorama). When confronted with this picture one of the anonymous reviewers said: “I’m not sure it needed the full HDR treatment, which in my mind adds a level of un-reality to what is otherwise a good shot.” Inadvertently Mr. Anonymous uncovered a profound truth in his remark. The only thing is that Mr. Anonymous didn’t realize that all pictures are profoundly unreal. There is no purity in art. Every image, no matter how it is made, is completely artificial. There is no ‘realism’ in photography as a good look at that Ronda picture will tell you.
So here is my manifesto:
a. Every picture is an artifact pure and simple.
b. Multiple-image and single-image HDR are just passing phases and they will be replaced with a camera that supports extended brightness ranges.
c. We should investigate the older decorative aesthetics in order to find guidance to this new world of the continuously articulated picture space.
d. Stop the flames. Flames will not help us. There is nothing sillier than grown men (and we are mostly men) arguing about the appearance of a picture. We can learn from everyone.
e. Let’s stop beating up on the extreme-color people. This nearly out-of-gamut color is a mark of the earliest phases of HDR. No one, even the designers, really knows how to use these sliders for optimal results. Most books on HDR recommend that you move the sliders around and ‘play with them’ in order to learn how it’s done. There’s a place for expressionist color in photography as much as there is a place for it in painting.
f. We have much to learn from our painter cousins. They have been practicing local brightness optimization for centuries before Chevreul pronounced the Law of Simultaneous Contrast of Tones. They could instruct us if we had the humility to listen.
g. We have an important task in hand and that is: How is HDR to be controlled? How, for example, do we modify brightnesses without modifying colors? What shall we do about the noise in single-image HDR? What shall we do about the lack of contrast inherent in all HDR? What does it mean (if it means anything) to tone-map color? How many images is optimal in multiple-image HDR before the lowered contrast degrades tones in the brightness ranges of interest? We need to know the answers to these and a myriad of other basic problems before we can convince others that HDR is the advance which it really is.
h. I mentioned it above but, above all, humility. Wynton Marsalis says: ‘The humble get better.’
Robert Consoli

Amen!

This is a wonderfull read. I use HDR as a tool not a means to a end. Hdr solves problems for me and yes its fun. You have written a serious statement.
Great read Take care

Robert,
You put forward some good points.
However I would make a couple of comments:
Proponents of Pseudo-HDR imaging, for that is what it is technically referred to when operating off a single exposure, are working with one hand tied behind their backs before they start. One image is simply incapable of providing the dynamic range for adjustment which multiple exposures provide. This is not to say that single exposure RAW images are not capable of tonal improvement utilising HDR software. But yes, if you want to use HDR in fast sports situations, then this is one solution, although I suspect there are workarounds in Photoshop layering and masking which I am unfamiliar with, to achieve similar apparent freezing of the moving object.
The second issue I would address is your contention that it is very difficult to take multiple exposures which will line up perfectly. To attempt to do so, handheld, is asking for trouble. There are very few serious professional photographers, particularly of landscapes, who do not use a rock-solid tripod and either delayed action exposures or remote control initiation of the exposure run. Where you are using very small apertures for great depth of field, and hence slow speeds particularly with fine grain ISO settings, there is no proper alternative to a solid tripod.
Reference your Question “g” on modifying brightness without affecting colour, I suggest you take alook at HDRPhotostudio…
CWJ

Hello All,
I am currently travelling and time constraints don’t allow me a detailed reply but it would be churlish not to acknowledge all the positive feed back from you who have read my (long) statement. Thank-you to all. Just to set the record straight. Well done multiple image HDR is surely always going to look better in lots of ways than anything that can be done with a single image. I’m only trying to point out that single-image HDR has its place and, although there are technical limitations, these can be dealt with which is what I try to do on my site sihdr.blogspot.com. I encourage those who are interested to look at some of my posts (and I would love to have feedback on them). Best to you all and thanks again for the feedback.

Bob Consoli

Great words!!!I admire every single letter of this mannifest! The HDR is pure art,and as an art it must be free!

In my recent statement at hdrcreme.com I stated that multiple-image HDR was difficult to do and, for that reason, had a limited application future. Specifically I said this:

“Multiple-image HDR is difficult to do right. It’s almost impossible to align multiple digital exposures correctly as a look at most multiple-image HDR photos will clearly show. Even one pixel off will degrade the picture.”

Distance Error
1 inch 0.0005 inch
12 inches 0.006
100 inches 0.05
1000 inches 0.5
2000inches 1.0
3600inches 1.8
5280 feet 31.68 inches or 2 feet and 7.68 inches
10*5280 feet 316.8 inches or 26 feet and (about) 5 inches

The first thing this suggests is that the smaller the linear distance covered by a single pixel the smaller the error so, for any given subject and at any given distance, the HDR photographer should attempt to box the intended subject as tightly as possible consistent with his or her purpose. That way the number of pixels (which is fixed) covers the smallest angle and any misalignment is minimized. If our conceptual camera had a zoom lens that would let me box in only one radian at 100 yards the error would be immediately halved.

The second thing is that you should absolutely keep the number of exposures to the bare minimum to fulfill your artistic goals. (see Consoli’s conjecture at sihdr.blogspot.com). I think, (but I’m not sure), that the probability of a single misalignment grows only arithmetically with the increase in the number of separate exposures. For two exposures let’s say that the probability m of a misalignment is 1*m. For three exposures the probability of one misalignment is 2*m. For four exposures the probability of one misalignment among the four should be 3*m. If I’m right then that’s good news for multiple image practitioners. But I’m not sure and I invite my readers to consider this problem.

What is the probability of making such a misalignment given that the subject is absolutely still? I don’t know. Whatever it is it’s a function of the stability of the camera, whether the camera has a mirror or not, whether the mirror locks up or not, whether the shutter is released manually or by radio release etc., etc. (CWJ has already pointed out some of these factors) I confess that I have no way of approaching that probability using numbers. If the camera is absolutely still but the subject is moving then (for our conceptual camera and for any given distance) the subject has to move more slowly than the distances given from the time of the first shutter release to the time of the final shutter closure. Let’s say that the time to make all these exposures is 10 seconds. An object a mile away must be moving more slowly than 3.168 inches per second in order not to leave a horizontal blur after 10 seconds. This is 3600 * 3.168 inches or 11, 404 inches per hour or 0.18 mph. The average cloud probably moves much faster than that. That’s why we see so many HDR landscapes with blurred clouds.

But the multiple-image HDR perspective is skewed. The thing is, HDR is not an end in itself. It’s a means of extending the tonal range of camera capture beyond the pitifully narrow range that it currently supports. The magic was never multiple exposures (which are as old as photography itself. See Michael Freeman’s book on Digital Black and White Photography for a good and effective non-HDR approach using multiple images); the new magic is the tone-mapping algorithms themselves. They can be widely applied; they don’t require multiple exposures. There are other means to this goal of tonal extension. Support by the camera manufacturers of more capable sensors is the ultimate winner. There’s some evidence that they’re starting to realize this. Multiple image HDR will always be the province of the enthusiast but I sincerely believe that due to its own severe limitations it doesn’t have much of a future. (There are too many subjects that just can’t be approached using multiple exposures and I find CWJ’s remarks about Photoshop unconvincing – although perhaps he can tell us in more detail exactly how that’s done.) It could be, however, that multiple image HDR does have a future in the studio. I’ve seen demonstrations (you probably have too) where exposures are made, lights are shifted, more exposures are made, etc. and all the exposures combined using Photomatix or the like. Great results can be achieved like this.

For a future post I (or we) need to consider sharpening as a cure for small misalignments but this is a very large and complicated topic and since I’m currently on a boat to Mykonos I don’t have the resources at hand.

Best to all and I look forward to CWJ’s reply,

Bob Consoli

Hello Mlibrescu,
When you’re ready to debate HDR topics in technical detail you’d be welcome at sihdr.blogspot.com.
There you can comment as much as you like and in as much technical detail as you like. The rest of us
would welcome you,

Bob Consoli

Great read from all of you. I’ve been an active member over at photo.net for over 4 years and I’ve only really just started HDR work. I absolutely am hooked on it, and just love the “look” of it. Unfortunately, and no disrespect to photo.net, it’s reacted to as if it was a bad word over there. Old school logic rules supreme and the photo elitists over there are resistant to new photographic possibilities. Rarely does an HDR do well (beyond my closest supporters) in the critique forums. People fear change, I suppose. Anyway…..I’m rambling. This site is so refreshing and an excellent place for me to spread my HDR “wings”.

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Mr. Consoli,

My apologies for being so late to the game on my comments to your “manifesto” however, I do believe your comments are worthy of further discussion.

“HDR is the most important development in photography since the discipline was invented.” While increasing the dynamic range of an image is important, I would like to know your reasoning to why it supersedes, such notable inventions as Kodachrome, cellulose acetate (safety film) base, dye transfer, etc.

“It is not an idea about color. Color is lovely and because of that people always assume that color is more important in image-making (painting or photography) than it really is.” Is this really a true statement? From its inception, photography was a monochromatic endeavor. The medium was monochromatic for nearly 80 years before the first viable color process (Autochrome) was invented. It was nearly 110 when Kodachrome was introduced. Given that black and white imagining is still being practiced and digital solutions are continually being developed to create black and white images from RGB images it’s not that “…color is more important in image-making”.

“All painting and photography is a meditation about brightness.” Is it brightness or dynamic range you are addressing here? I posit that a better way of describing this is Chiaroscuro – the tonal contrasts that exist in many images that help create depth and luminosity in an image (think Ansel Adams “Moonrise over Hernandez New Mexico”). The range of tonal contrast and the where those relationships exist next to each other in the image is more important than brightness.

“Tone-mapping techniques have led to the potential rejuvenation of every photograph ever taken as long as we have it in its original form (RAW file, TIF file, photo negative, etc).” There is more to an image than dynamic range and the ability to expand that dynamic range. A poorly composed image will still be a poorly composed with an expanded dynamic range.

” Stop the flames. Flames will not help us. There is nothing sillier than grown men (and we are mostly men) arguing about the appearance of a picture. We can learn from everyone.” While I agree that poorly worded attacks against a photograph are inappropriate, the need for open honest critique is required if any genre is to grow and its practitioners improve.