Ansel Wasn’t an Oracle

Rusty Truck

Ansel Adams famously said that the negative is the score and the print the performance. Ansel was one of the great lights of 20th Century photography and his writings are generally very good. In this case, though, I think this famous quote has become a little outdated by technology changes.

I love this quote and have been guided by it for a long time. As I began to understand it more deeply, it was empowering. For a long time my work was basically a documentary or reportage style. It was very literal photography of scenes in the natural world. I even for a time subscribed to the false doctrine that if an image was altered in any way it was no longer pure and virtuous.

Ansel’s quote helped me understand that that had never been true and was not a worthy or even useful goal. At least for me. I truly believe that the negative (raw file now) is only a start. It usually must be perfected by the artist to become art rather than just a record of something.

The darkroom process

Let me talk a little about the darkroom process, as I understand it. This is so I can contrast it to the current workflow. I will confess that, although I built a darkroom in my basement, I only ever used it for a few black and white images. About that time I discovered a new program called “Photoshop”. 🙂

The image captured on film is generally considered “read only”. It is never modified. There are exceptions to every rule, but this is by far the typical case.

The extensive set of transformations and modifications that can be applied to the negative in the course of printing are done in “real time”. That is, it is a dance involving adding or holding back light from certain areas during the time the paper is exposed to light. It can also involve variations of development time or chemicals and even manual operations like bleaching or spotting of the print.

Given this workflow, it is completely appropriate for Ansel to describe it as a score that will be performed by an artist. The outcome will vary somewhat with each performance, depending on the feelings and inspiration of the performer. Each print is a unique creative process.

The digital workflow

Fast forward now to the current generation of digital imaging. Digital imaging is wonderful in too many ways to list. I absolutely believe it is superior to film in almost all important respects. There is no reason for most artists to ever want to go back to film and chemicals. Your mileage may vary, but that is a personal artistic decision.

One of the places where digital processing is most different is in the post processing to complete the image. The raw file (the “negative”) is processed in the computer using software like Photoshop.

The software allows extensive, non-destructive manipulation of the image. The great dynamic range captured by modern sensors now gives us far more information to work with and more freedom to transform the image. It is easy to remove distracting elements, composite images together, and vastly change the tone and color profiles and even exposure.

Ansel had to select a type of film to use prior to taking an image. He also had to use color filters to change the tonality of his black and white images. It was a guessing game based on lots of experience. He called it “pre-visualization”. Now we retain all the color information until processing time and we can convert to black and white via multiple types of software transforms and with extensive control over tonality. Much more subtle artistic decisions can be made. He would have loved it.

Furthermore, these changes are built on the computer and recorded as a complete package. All the modifications can be done slowly and I can backtrack, undo things I don’t like, try alternatives, even easily create multiple versions of an image.

The “performance” aspect of Ansel’s darkroom manipulation now becomes a considered, one-time transformation. All the artistic decisions are immediately seen on my nice color corrected monitor. I can study the effects at leisure and decide to change them. When I am done, I have virtually a finished image.

The print

It almost sounds like printing has been reduced to a minor step. Not so. It is still a complex artistic process. But again, the digital world gives many new options.

Choice of paper is a big deal. It controls a major part of the look of the resulting image. A glossy Baryta has a very different look from a matte watercolor paper. Paper with varying textures and base color can be selected.

This is assuming you are printing yourself. I recommend it. It is a joy and it connects you with the final product. But many other options are available. You can have your image rendered on canvas, metal substrates, acrylic, transparencies, cloth – too many to list. All vary the look and potential use of the final image.

But the thing that is ultimately the most different from film days is that the artistic result has been determined prior to hitting Print or sending the file to the producer. Each time you print the image, the results should be so repeatable as to be indistinguishable. As Alain Briot said, somewhat tongue-in-cheek I think, this is one of the problems with printers: they do not need our help in any way while they do what they do.

So, in a way, a print is like a good illusion. The magic happens before we ever see the print appear. This is a huge contrast to the film days where creating a print required a virtuoso performance in the darkroom.

Was Ansel right?

I believe Ansel was completely right and very insightful when he wrote this famous quote. Like with many things, though, time and technology changes. Since he was describing a particular technological process, it is not surprising that it will change.

The real genius of the quote, and the reason I believe it is still useful, is to point out that the captured image is only the starting place. I am free to apply my vision to complete the image. Without that injection of originality, it is too easy for it to just be a snapshot.

How that is done is not that big of a deal. Art is a physical product and expressed via currently available technology. The technology should not determine an artist’s vision. Make it your own.

The quote was an observation by a great and experienced artist. It did not come down from heaven written on stone. Don’t be limited by changes of process or technology. Understand that it frees you to create!

What is DPI?

An extensively processed image

DPI is simply an acronym for “dots per inch”. It should be a simple concept, but people sometimes get twisted up in knots over it. Our printer manufacturers have not helped the situation.

What are “dots”?

Unless you are reading a printer spec sheet, dots just mean pixels. A pixel is a “picture element” – the smallest piece of a digital image. By convention, a pixel is a triplet of red, green and blue values. That sounds very technical, but it just means they are 3 values carried around together, say something like 95, 134, 47. By convention each value can have a range of 0 to 255. That is not representative of what camera sensors really do anymore, it is the convention. The convention comes from the 8 bit representation of color values way back in early times. The maximum value 8 bits of binary data can represent is 255. The practice has been established and perpetuated by Photoshop over the years. The actual data range we use is a subject for another post.

The image that gets stored in your computer is a grid of pixels. The camera I am using most often right new creates an image that is 8256 x 5504 pixels. That makes a lot of data!

A fuzzy quality metric

Your camera does not know the concept of DPI. As a matter of fact, DPI is a fairly useless term unless you are printing an image.

Have you ever had someone tell you they need a file that is 8×10 inches at 300 DPI? Unless you are sending the file to whoever does your photo printing, it really means they do not understand what they need.

At best DPI is a metric for the quality of an image viewed or printed at a certain size. The more pixels you have in a given distance, the better the image should look, in general.

But in most people do not even know the pixel resolution of their screen or printer. If you save a file in jpg format there is a good chance the default is 72 DPI. This was considered the “normal” screen resolution – way back. The main monitor I use is 219 DPI. And it is several years old. And I don’t really care, because that is a number that is never important to me. I never use it for anything.

DPI really doesn’t matter for the screen

One of the reasons DPI doesn’t mean much for most of us is that our computers scale images for viewing on our screen. And they usually do a really good job. But what most apps do is map the pixels available to the pixels of the screen. So if you look at a file that says it is 10″x10″ at 72 DPI, you will see a 720×720 pixel image. It will be however large 720 pixels measures on your screen.

When you view an image on your screen all that really matters is the resolution. The DPI number is generally ignored.

Size matters

If DPI is not as important as many people think, then is resolution unimportant? No. Absolutely not. The number of pixels you have to work with is always an ultimate limitation of what you can do with the file. As is said in many things, size matters.

With plenty of pixels imaged through good glass you have the flexibility to print large, or to crop tightly or to create images of astounding detail. Also, massive numbers of pixels gives sharper edges and smoother gradients.

DPI for printers is a whole different thing

The major printer manufacturers have confused the issue for us. A printer ad may proudly proclaim it does 4800 DPI! This is technically correct, but not helpful. They are talking about the density of ink drops they can lay down on the substrate (paper). But printers do not print pixels.

A drop of print ink is not a pixel. You do not send the printer an image scaled to 4800 DPI!

A printer takes the pixels available in a given area and transforms them to densities of the subtractive colors needed to come close to reproducing the colors and gradations contained in the original pixels. This is a complex technology and I will not attempt to explain it here. Sufficient that you remember a drop of ink is not a pixel.

Where DPI means something

When you know how large of a print you wish to make then DPI becomes meaningful. The number of pixels available combined with the desired print size give us the DPI. DPI is a measure of the amount of information available for an inch of print.

For optimum printing the guideline is supplying a source file of around 250-360 DPI. This gives the printer driver enough information to do the ink transform we talked about above.

My Canon printer, for instance, has a “standard” resolution of 300 DPI. It can print well with a range of values, but this is considered optimal. This means that one of my image files of 8256 x 5504 pixels could be used to print an image of 27.5″ x 18.35″ with no scaling or loss of resolution. That is the size of this image at 300 DPI.

If I want to print one of my images at a more typical size, say 18″x12″ I could scale a copy of my master file down to 300 DPI. Or not, because Photoshop or Lightroom is perfectly capable of scaling it down when printing with little discernible degradation. One person even says that higher DPI gives better results.

If I have an image with insufficient pixels I could just try to print it. Printer drivers do amazing things. Or I could scale it up in Photoshop, which also does an excellent job within limits.

It’s those limits that you have to be able to estimate. If you have a 2 MPixel image and you want to print it poster size, well, your results probably will not meet your expectation. No free lunch.

Conclusion

So what about DPI? Don’t sweat it unless you are printing. Only if printing is it a meaningful metric. And it is only meaningful when you are taking about a particular image printed at a particular size.

There are plenty of technical issues to stress out about. This should not be one of them, unless you are producing high quality prints.

Night Photography

Night photography sample

Most people put away their cameras when the sun goes down. But night photography can be a wonderland of visual interest. It does require some new disciplines and knowledge, though. It’s a different world at night.

What’s to know? My camera has excellent exposure metering. I just point it at the subject and take a picture. Right?

Well, your mileage may vary. If you are taking pictures with your phone or taking jpg images, you will get pretty good results sometimes. That is because the jpg processor is making many creative decisions for you to try to render an image it thinks you wanted. If it guessed right it might do an OK job.

With night photography, more than many other types of image making, you really need to be the decision maker in charge of your images. Your intent determines how you approach each scene. The type of subject, the type of light available, whether or not movement is desired, the mood desired, weather conditions, etc. all factor in to the strategy. And most of these factors are interrelated.

Type of image

A portrait at night will (probably) require a well lit subject. This may involve external lights and/or reflectors. A star field scene, on the other hand, may have just a vague or silhouetted foreground. No lights, but you need to know good techniques for capturing the stars as crisp points. A cityscape at night may require very long exposures to streak car lights.

Movement

A big decision is if movement is desired or not. Some possibilities: a street scene with everything crisp and frozen, a street scene with car lights and people streaked, a star field with crisp points of light, a long exposure star field with obvious streaks from rotation of the sky, a portrait with a crisp subject but blurred background motion. Each of these requires a different exposure approach and different planning and preparation.

Motion is often one of the signature characteristics that distinguish night images. It is something you completely control by your exposure settings.

Mood of image

The time of day, the subject matter, and your desired treatment establish the mood of an image. Time of day? We’re talking about night. Well, “night” starts at different times. There is sunset, twilight, dusk, blue hour, and full darkness. I don’t have space here to discuss each one, but I love all of them and enjoy making images in each. Probably blue hour and full dark are my favorites, except I can seldom resist a beautiful sunset.

Blue hour probably deserves some discussion. This is the time after the sun is completely gone and the orange glow is gone from the sky. The sky is a rich, dark blue and still light enough to set off a foreground like city lights. It is a beautiful time of day. Blue hour is perfect for some city skylines and for some landscapes.

Full dark is required if you want to see the stars. It is probably necessary if you want long exposures like smoothly streaked car lights.

But all of this is modulated by the desired result. Do you want dark and gritty or more cheerful and upbeat? Is it a realistic image of architecture or an abstract?

Full manual control

You will usually need to override the auto exposure of your camera. The poor exposure system with fail miserably trying to determine what you want if you point it at an almost totally black sky. So a camera with full manual control is required. You will need to determine and set the ISO, aperture, and shutter speed yourself.

This is not as bad as it seems. You will learn some guidelines for initial settings for the scenes you most commonly shoot. And with digital, it doesn’t cost much to shoot some test shots. Since you can get immediate feedback you will quickly zero in on the correct settings.

Technology and technique

Night photography is an extension of normal daylight photography. Some new techniques must be learned. They are specialized, but most are pretty straightforward.

Night photography generally implies longer exposures. This implies keeping the camera rigidly positioned. Therefore a good tripod is almost a necessity. And a shutter release to minimize camera shake when you press the release button. And if your camera is an SLR with a mirror, you need to know how to lock the mirror up to eliminate shutter slap motion.

Let me emphasize again, a good tripod is necessary. Don’t scrimp on this. Get the best you can afford and use it all the time. I generally use Really Right Stuff tripods and heads (I get no compensation for this), but I know that Gitso is also very good. There are many good tripod manufacturers, I just don’t have first hand experience to allow me to recommend others.

Unless you are going for really long exposures, you will often need to use a high ISO at night. Many modern digital cameras have excellent high ISO performance. If you go back to film days or early digital cameras, you probably think of ISO 800 as a really fast and grainy setting. Not anymore. On the Nikon Z7 I use now, noise is hardly detectable at 3200!

Another example of a specialized night photography technique is the “rule of 500”. Like all photography “rules” it is a guideline. It can be a helpful starting point for setting up a night sky shot. For a full frame camera, set the ISO to 3200 and the shutter speed to 500 / [focal length] seconds. So using a 24mm lens, that is 500/24 or approximately 20 seconds. This is a great guideline to memorize for when you are out in a really dark place at night trying to get the night sky exposure tweaked in.

Noise

Noise during the image capture is a potential problem unique to digital sensors. At least we do not have to try to estimate reciprocity failure as we did with film. Noise in electronics is a function of temperature. Long exposures power the sensor much longer than usual, which can heat it up and increase noise (it looks kind of like grain).

Most camera manufacturers provide a setting to have the camera take a dark frame immediately following an exposure. This gives a noise sample which is automatically subtracted form the image you just took. This does a pretty good job of compensating for the sensor noise. Sometimes you will want to use it and sometime not. I usually do not, because it is often cold when I am out, which minimizes noise. The main cost of the noise cancelling is doubling the exposure time. If you set a 20 seconds exposure it will immediately follow it with a 20 second noise sample.

Post processing

Post processing is almost always required, in night images or any others. It is common to want to reduce luminance and/or color noise, to make the blacks deep and full, to sharpen, and, for some scenes, increase saturation or contrast.

I mention it here, not because night photography necessarily needs it more, but to emphasize that you need to shoot RAW and always post process.

After the sun goes down

A whole new world opens up when the sun goes down. Don’t put your camera away as soon as sunset fades! Get out and experiment. Try some different things. You don’t have to go to Moab and shoot grand night sky shots of the Milky Way with arches in the foreground. Experiment in your city. Learn to be confident manually setting exposures. Practice until you regularly get the results you want.

Try it! Don’t worry about failing. It can be fun and instructive! I ended up loving some of my failures.

Is Black & White a “Thing”?

Fields at sunset, black & white

Is Black & White photography an art form in its own or is it a way to salvage images that just didn’t work in color? Hear me out before you flame me. I love B&W and believe it is a special medium.

History

Black & White is where we started. It is our history and beginning. Looking only at commercial films, the early world was totally black & white. There were a variety of film designs, with tradeoffs of speed, contrast, fog level, etc. Because processing was done chemically, the entire roll had to be exposed at the same speed. Generally, a photographer became familiar with a handful of films. Lots of work was required to become familiar with the film’s exposure characteristics. Different films were selected for different uses and effects.

In the black & white days lots of work was done in camera to adjust the tone values. Filters, usually red or orange, were used while shooting. Their selection was based on the artist’s subjective judgement of predicting the outcome.

The system worked pretty well for decades.

Color

Then along came color. It really took off in the 1950’s with the introduction of Kodachrome.

Finally ordinary consumers had what they thought they were missing – a color image. Color film sales dominated black & white.

Digital

In the early 2000’s digital cameras became practical and affordable. Now color film was eclipsed and it virtually disappeared from the market. Digital had better resolution, better dynamic range, it was cheaper, and we could print our own pictures on cheap inkjet printers.

So why, with all these advances, does anyone care about black & white anymore?

Digital saved black & white

The technological benefits that made digital imaging take over mainstream photography also brought huge advances to black & white images. A modern sensor is amazing. It captures more information than black & white film and it captures and retains the color information. This can be used later to tailor the tonality of the b&w image. And it allows far more control than color filters and a chemical darkroom.

The tools we have, like Lightroom and Photoshop, are very advanced and are able to exert a degree of control that would have been unthinkable in the film days. At the same time we have highly mature multichannel inkjet printers with sophisticated inks giving us archival prints. Added to that the development of many types of papers for printing and the options available to a black & white artist today makes this a golden age.

Why black & white?

But color is readily available and everyone can print it cheaply. Why would anyone still want black & white?

This gets to the heart of the issue. A black & white print is perceived as an entirely different experience. Black & white sheds the distraction of color. What is left is tones, shades of gray. These emphasize the shapes and forms of things. Composition and graphic design comes more to the fore. It is an alternate view of reality. That causes us to look at the image differently.

This difference is the beauty of it. It is a different interpretation of the world. The viewer immediately sees it is different and the artist can lead them through his composition more easily to see what he wants to emphasize.

I have heard photographers say “this didn’t work in color, lets try black & white”. That is a very limited perspective. I would turn it around and say “this image really needed the color information to make it work, so we can’t do it in black & white”.

Ansel Adams once said “the negative is the score, and the print is the performance”. This is still true, except the negative is a raw file and the print and processing are all done digitally. No dark room. No chemical mess.

So is black & white a thing in its own right? Definitely! It is a great art form with a long and glorious history. Today is the best time ever to be doing or viewing black & white images!

The Sensor

Rock in river, sunset

Putting up a nice safe technical post this week. What is the sensor and why do I care? If we just click the shutter button and expect to see magic happen on our screen, isn’t that enough? No, I obviously do not think it is enough or I wouldn’t be writing about it. The sensor is the heart of the technology of image capture. Without a great sensor none of this would be possible.

History

Going back, there was rubbing pigment on the wall of caves – Oops, too far. Photography as we would recognize it started in the early 1800’s. Motivated photographers had to mix their own chemicals and wet coat their own glass plates, in the field, in the dark, right before exposing them, then processing them quickly, in the dark, in the trailer they brought. Not for the short attention span crowd.

In the late 1800’s Kodak produced commercial coated transparent film, on a nitrate base. Keep it away from your candles – poof. A few years later cellulose based safety film was invented and replaced the dangerous nitrate film.

Around this same time roll film was also invented, so more than one exposure could be made before changing film. This was a contribution to most photographers. Leica’s adaptation of the 35mm film size and the development of an excellent, small hand held camera system greatly advanced the use of photography. In 1935 Kodak released one of the greatest advances in photography – Kodachrome film. Color photography was finally practical and it became very popular. A very large market for both color and black and white film developed with Kodak, Fuji, Agfa and many other brands vying for position.

This is not an exact history of the development of photography and all of its branches. The point is that the technology of recording images has always been central to photography and it has been a subject of heated discussion/argument by photographers. I have witnessed people almost coming to blows about Kodachrome vs Fuji Velvia.

Film Was Our Sensor

Most “serious” photographers had their 2 or 3 favorite films that they used regularly. They learned the characteristics of each well enough that they could predict the results. This is very important, because photography has always been a mixture of technology and art. How the sensor (film) records light is necessary to know so the artist can determine how to use it to achieve the results they want. Pushing the limits of the sensor technology was a common artistic effect.

But then photography’s “shot heard around the world” happened in 1975. From Kodak’s web site: “Kodak invented the world’s first digital camera. The prototype was the size of a toaster and captured black-and-white images at a resolution of 10,000 pixels (.01 megapixels).” From that trivial sounding start, Kodak killed it’s own business and the multi-billion film business around the world. Digital sensors forever changed the course of photography. And this was a good thing for photographers.

Digital Image Capture

Image capture in a digital sensor is completely different from film. Instead of photons of light causing a chemical reaction in the film, the photons caused the emission of electrons in the sensor chip. These electrons are accumulated over the duration of the exposure, then transferred out serially and sampled to “count” the electrons. From this, complex and high speed processing reconstructs an array of “pixels” (picture elements) which is so dense it fools our eye into seeing a smooth image. This constructed data set is recorded onto a memory chip in the camera. Then usually transferred to a computer.

Over the years, good engineering has improved the process so much that few people still argue that images from film are superior to digital captures. My personal transition happened in about 2004. I finally concluded that the Nikon D70 was at least at parity with 35mm film. That was a 6 Mega Pixel sensor. The image accompanying this post was shot with that camera. Now, when I look at a good quality scan of a 35mm slide compared to a capture off my 47 Mega Pixel Nikon Z-7 sensor I have to shake my head and marvel at the improvement of our photographic technology. Yes, some of this comes from greatly improved lens design, but the sensor is one of the biggest effects.

So with digital sensors I am free to push the limits more, to experiment more, to have more fun with photography, to post process to a much larger degree. Sensor development has removed many of the barriers of resolution, dynamic range, reliability, noise, etc. Photography now can be driven more by artistic vision than by a struggle to produce a usable image.

Do We Need To Understand the Technology Anymore?

Do we as artists need to know about the technology of our sensors? I believe YES. Photography is unique in being a strong mix of technology and art. A good craftsman cannot ignore either of them. These marvelous devices must be understood to be used to their full potential. Digital sensors have limitations and their own quirky characteristics. Dig in; understand the transfer curves; understand the dynamic range; understand the behavior at maximum brightness or darkness; understand noise; understand moire patterns. Understand other related things like the focus system in your camera. Nothing is trivial. But have a very high regard for the sensor.

Much more can be written about the sensor. I may in the future if requested. As an engineer I enjoy digging into the technology.

To the sensor developers at Kodak and Nikon and Canon and Sony and Fuji and all the others – Thank you!