Ed Schlotzhauer

An artists journey

Category: Photography

  • How Big Can I Print It?

    How Big Can I Print It?

    One of the things we have to wrestle with when we want to make a print is how big can I print this image and get good results? And how large should I print it? There is a lot of advice out there. Some of it is good.

    Film vs. Digital

    Virtually all images have to be scaled up for printing. The print you want to hang on your wall is many times larger than the sensor or piece of film you start from. Hardly any of us are shooting 8×10 negatives these days. Even if we are, we still usually want to make larger prints.

    The technology has changed completely from the film days. Enlargement used to be optical. By adjusting the enlarger lens and the distance from the film carrier to the print surface, the image was blown up to the desired size. If the lens is good, it faithfully magnifies everything, including grain and defects. If the lens is cheap, it enlarges and introduces distortion and blurring.

    Digital enlarging is a totally different process. A digital image is an array of pixels. My little printer at my studio likes to have 300 pixels/inch for optimum quality. So if I want to make an 8×10 print and I have at least 2400×3000 pixels, it will print at its best quality without changing a thing. Digital enlarging is a matter of changing the number of pixels.

    Digital enlarging

    But usually I want to print a larger size than the number of pixels I have. Here the digital technology gets interesting. And wonderful. Going back to my example, if I want to make a 16×20 print and maintain best quality, I would have to double the pixels in each dimension. It would have to go to 4800×6000 pixels.

    Photoshop has the ability to scale the number of pixels in your image. There are several algorithms, but the default, just called “Automatic”, usually does a great job. Here is the difference from film: software algorithms are used to intelligently “stretch” the pixels, preserving detail as much as possible and keeping smooth transitions looking good. Lightroom Classic has similar scaling for making a print, but it is automatically applied behind the scenes. Smoke and mirrors.

    The result is the ability to scale the image larger with good quality.

    Print technology

    In a recent article I discussed a little of how an inkjet printer makes great looking prints using discrete dots of ink. There are other technologies, such as dye sublimation or laser writing on photosensitive paper, but they are far less used these days.

    It should be obvious, but to make a really big print, you need a really big printer, at least in the short dimension of the print. Really big printers are really expensive and tricky to set up and use. That is why most of us send large prints out to a business that does this professionally.

    Why do I say the printer has to be big in the short dimension of the print? Past a certain size, most prints are done on roll feed printers. They have a large roll of paper in them. Say you have a printer that prints 44″ wide. The roll of paper is 44 inches wide and many feet long.

    We want to take our same 8×10 aspect ratio image and make a 44×55 inch print. If it was film, we would require an enlarger with at least a 44×55 inch bed and a cut sheet of paper that is 44×55 inch. But an inkjet printer prints a narrow strip at a time across the paper. The heads move across and print a narrow 44 inch long strip of the image, the printer moves the paper a little bit, and it prints another narrow strip. Continuing until it has printed the entire 55 inch length. Then the printer automatically cuts off the print.

    But if we naively follow the recommendations for optimum quality, we have to scale our poor little 2400×3000 pixel image up to 13200×16500 pixels. Even the best software algorithms may introduce objectionable artifacts at that magnification.

    Viewing distance

    Maybe we don’t have to blindly scale everything to 300 (or 360) pixels/inch.

    A key question is: at what distance will the image be viewed? Years of studies and observation led to the conclusion that people are most comfortable viewing an image at about 1.5 to 2 times the image diagonal length. This lets the natural angle of the human eye take in the whole image easily. For the example we have been using of the very large print, people would naturally choose to view it from about 105 to 140 inches.

    Along with the natural viewing distance there is the acuity of the human eye. I won’t get into detail, but the eye can resolve detail at about 1 arc minute of resolution (0.000290888 radians for the nerds). Simply, the further away something is, the less detail we can see.

    Going through the calculations, if our audience is viewing the large print from 1.5 times the diagonal, it only has to be printed at 33 ppi! Finer detail than that cannot be seen from that viewing distance.

    I have heard photographers who have images printed for billboards or the sides of a large building talk about inches/pixel. It would look like Lego blocks up close, but it looks sharp from where the viewer is.

    Nature of the image

    This is true unless the audience is photographers. They are going to get right up to the print, as close as their nose will allow, to see every blemish and defect. 🙂 But normal humans will view it from a distance.

    There are modifications to the pixels vs. viewing distance calculations depending on the nature of the image. If the image contains highly detailed structure it will encourage viewers to come closer to examine it. If the image is very low contrast, smooth gradations, it could be even lower resolution.

    Printing at the highest possible resolution that you can for the data you have is always a good idea.

    Your mileage may vary

    How big of a print can you make? It depends – don’t you get tired of hearing that? It is true, though. The real world is messy and simplistic “hacks” often don’t work well. It is better to understand things and know how to make a decision.

    When it comes down to it, these are great times for making prints, even large ones. My normal print service lists prints as large as 54×108 inches on their price list. I know even larger ones are possible.

    How big should you print? How big can you print?

    Conventional wisdom is that scaling the pixels 2x each dimension should usually be safe. My camera’s native size is 8256×5504 pixels. Scaling an image 2x would be 16512×11008 pixels. This would be a “perfect” quality print of 55×36 inches on a Canon printer. I have yet to need to print larger than that.

    Given the perceptive effects of visual acuity, I am confident I could create much larger prints. Larger than is even possible by current printers. And they would look good at a reasonable distance.

    A key question is who are you printing for? A photographer or engineer will be right up to the print with a magnifying glass looking at each pixel. Most reasonable people will want to stand back at a comfortable distance and appreciate the image as a whole. Who is your audience?

    Learn how to scale your image without artifacts and how to use print shapening to correct for problems. Know the perceptual effects of human visual acuity. This is part of the craftsmanship we have to learn in our trade. Given those tools, the rest is artistic judgment. With today’s equipment and careful technique and craftsmanship we can create wonderful results.

    Your mileage may vary.

    The image with this article is very small – 3 MPix. I would not have a problem making a 13×19 print of it. I doubt you could see the pixels.

    Have you tried to make large prints? How did it go? Let me know!

  • Pixels, PPI, DPI

    Pixels, PPI, DPI

    Pardon me, but sometimes the Engineer in me has to rant. I see so much confusion about pixels and how to scale them to an output size. Pixels are just an RGB dot. How they are presented is up to the output driver. It is complicated at a technical level, but it does not have to be complicated to us poor users. So let’s see what pixels and PPI (pixels per inch) and DPI (dots per inch) really mean mean.

    What are pixels?

    A digital file is just a rectangular array of pixels. The term “pixel” is a contraction of “picture element”. It is the smallest dot the sensor can resolve or the smallest point of light a display can produce.

    Getting to the array of pixels is complicated, since camera sensors don’t read them directly. See my article “How We Get Color Images“. Regardless of what magic actually happens, by the time you view an image on your computer monitor, it is an array of pixels. Conceptually each pixel is represented as a triplet of (Red value, Green value, Blue value). Each of the values is a number from 8 to 16 bits in size. So each value has a magnitude of 0 to 255 or 0 to 65536. What sizes you actually have is determined by the capability of your sensor (the dynamic range) and camera and the color space you are using.

    Pixels have no physical meaning. In the main camera I use, the array is 8256 x 5504 pixels. Again, it is just a number. It has no physical meaning. It has no relation by itself to a print size or the size of the image on screen.

    What PPI should I use for display?

    This is the thing that annoys me the most. I constantly see museum and gallery directors put out requirement that we have to send in electronic samples sized to 72 PPI. PPI stands for pixels per inch.

    Way back in the dim distant past, computers only did text. Then Apple came along and wanted to do graphics. They did research and decided 72 PPI looked good on screen. This set the standard, but hasn’t been the case for eons of computer age. The display on my fairly old iMac is about 218 PPI, physically. But the magic 72 PPI stuck with a lot of people.

    The increases in PPI density and bit depth and speed of monitors is one of the great technological advances of computers in recent years. All those pixels on screen makes for very sharp and smooth images. We can see so much more.

    Worse, many people have been led to believe that the PPI sizing of the image files means something. It doesn’t anymore. Actually, it never did for images displayed on screen. The PPI setting has little or no meaning for an image displayed on screen.

    Try it

    Try an experiment: take an arbitrary, fairly large jpg file of your choosing. Let’s say the filename is MyFile.jpg. Load it into Photoshop and resize, WITHOUT RESCALING, to 72 PPI. Save it as MyFile-72.jpg. Now reload the original file.jpg and size it to 360 PPI. Again without rescaling. Save it as MyFile-360.jpg. Rescaling changes the number of pixels in the file. We just want to change the PPI setting. These 2 files now have the same number of pixels but different ppi scaling.

    Now use whatever image preview application you like and view the 2 sized files. Is one of them 5 times larger than the other? On my system, they are exactly the same size on screen. Even though one is set to be 72 PPI and one is 360 PPI. They are displayed as the same size and the same resolution.

    Why is this? Because the file PPI setting means nothing. The display app just looks at the number of pixels and decides how large it is going to make it. If it is a tiny image, say 300×200 pixels, it will probably make it very small to avoid pixelization artifacts when an image is enlarged too much. It it is a reasonable sized file, it will just pick a good output size. It makes these choices based on the number of pixels. If the image is in a web page, the web page code determines the size the image will be.

    What PPI should I use for print?

    Now we head into an even more confusing area, and here the confusion is somewhat justified. Printing is it’s own special world. The technology and perception is very different from displays. Displays emit light. Prints reflect light. The effect to the viewer is very different.

    Printers don’t have pixels. Instead, we refer to the output scaling as DPI – dots per inch. This recognizes that we are now talking about physical marks on paper (or your substrate of choice).

    The printer manufacturers have created tremendous confusion in customer’s minds because they overload terms. The Canon Pro-1000 printer I have at my studio has a specified print resolution of 2400 DPI horizontally and 1200 DPI vertically. Yet the optimum print resolution is 300 DPI. That is, when I am creating a print, I should try to set the output resolution to 300 DPI. This is bound to confuse most people. Why not set the output to 2400 dpi for maximum resolution?

    How inkjet printers make nice prints

    We come to one of the secrets of printers. We customers want prints with crisp lines and smooth gradations of color and tone. As natural as film used to be, or as smooth as the original artwork we are copying. An inkjet printer sprays dots of ink onto the paper. A dot or no dot. At the level of a single dot, this is not smooth. Inkjet inks do not “mix” to create new colors.

    So take my Canon printer as an example. Each “dot” (at 300 per inch) is actually subdivided into an 8×4 grid – 8*300 is 2400 dots per inch horizontally. Any position in this 8×4 sub-grid can contain any combination of printer dots of any of the 12 colors. The print driver uses a magical algorithm called “error diffusion” to cover the sub-grid with a blend of printer dots of the available colors that simulate the color and intensity of the pixel to be printed there.

    It is mind bending in it’s complexity. One reason they don’t talk about it much is that it is proprietary for each manufacturer and printer, a closely kept trade secret. The good news is that they take over this complexity so we don’t have to. And they do a very good job. So I set my image to print at 300 DPI and magic happens.

    It usually doesn’t matter

    In summary, PPI settings do not matter for images displayed on your monitor or on the web or sent to your social media account. If someone tells you they need their images scaled to 72 PPI, just smile and do it, but secretly know they do not know what they are talking about. Only the total number of pixels affects the size of the image. And without going into mind numbing detail, I hope this takes a little mystery out of the way printing works.

    I feel better now. 🙂 How about you? Are you more or less confused?

  • Thinking Black & White

    Thinking Black & White

    It seems to me I have been seeing and thinking in black & white more lately. Not seeing the world as black & white. Things are not that simple and clear cut. No, seeing the world as black and white images. That is the interpretation of reality I am leaning more to these days.

    Contribution of photography

    I believe black and white is one of the great contributions of photography to the art world. Yes, at the time it was a technical limitation rather than an artistic choice. The processes and chemistry of the late 19th century through mid 20th century could only create monochrome images.

    But the look stuck. It became associated with photography, with “reality” in image making. It helped establish photography as a distinct art form from painting.

    Because that is the medium they had, the practitioners of it became extremely proficient at creating beautiful, artistic images. A good artist learns how to use his tools. Some people say their achievements of the old masters of black & white photography have never been equaled. I’m not so sure. We can do a pretty good job today.

    Not obsolete

    Most people view black & white images as obsolete today. Why do that when we have a wonderful world of color imaging? Why throw away all that rich color information?

    The reality is that black & white is still a unique and vibrant art form. It can create very captivating images. Well done and well printed I believe we can still rival the best of the “old masters” like Ansel Adams.

    There are magazines that only showcase black & white. There are galleries that only accept black & white works. Some artists only do black and white. Why? Because many art lovers look to it as a wonderful medium for conveying emotion and feeling. It is still quite popular.

    Advantage of black & white

    But why? What advantage does black & white have? These days, since we have an equal choice between black & white and color, there must be a reason to chose black & white at times.

    Black & white is an abstract medium. Eliminating color brings a new and different view of the world. Without color the image becomes shades of tone and forms. It creates a whole new way of looking at things. It is clear that it is not just a representation of reality, it is an interpretation, a new view. The photographer could have worked in full color. So black & white was a conscious choice to show something different.

    Being so different, it is immediately set apart as something to be looked at in a new way. That helps with the reinterpretation of the scene. Plus, many viewers appreciate the pure tonal variations without the distraction of color. It becomes a new type of art.

    So creating black & white prints is no longer a technical limitation of the medium, it is an artistic choice. We use it because it can better express our view of the scene.

    Why now?

    As I said, it is an artistic choice. Some subjects seem to work better in black & white. There is a lot to be said for removing color distractions and focusing attention on tonal variations. Shapes and form and relationships take on a new prominence. It is a different interpretation of a scene.

    And the technology now shifts the work from the darkroom – in the dark and where you are breathing all sorts of chemicals – to the computer – in the light, maybe with a glass of wine nearby. Sounds more pleasant and creative to me. The masters, like Ansel Adams needed to make a number of test prints to work out the “map” of the dodging and burning and sharpening and spotting required to create the final print they like. Then they, or more likely their assistant, would spend many hours in the darkroom hand creating each print. Each print required hours of work.

    Now technology lets us push the time consuming work up front. I may spend hours on the computer working with an image to get it exactly the way I want. Then in a matter of minutes I can print it. If my systems are set up correctly, the print is a very good match of what I created on the computer. And I can push the button again and produce perfect duplicates every few minutes. The computer and printer technology completely changes the game. No more colored filters on black & white film, no more long sessions in the darkroom in possibly harmful chemicals, no more having each print be a performance piece that may of may not match the artist’s template.

    Technology-wise, this is the best time in history to be creating black & white prints. Artistically it is a great time, too. The world is saturated with color prints and black & white seems fresh and unique – a different point of view. It is time for a resurgence of black & white. At least for me.

  • Fall in Love

    Fall in Love

    I advocate it, but I’m not talking about a romantic meeting. Making art should be an act of love. We should fall in love with our works, or else, why do them?

    Because it’s there

    I mostly wander and explore without a lot of planning or result in mind. Sometimes I shoot pictures just because something is kind of interesting and I’m there to see it. That can be good, but usually not.

    Being an explorer, I follow my curiosity. I tend to try a lot of experiments to see what happens. So if something tweaks my interest I often see what I can do with it. Occasionally I have a tingle and excitement when I press the shutter, knowing that I have captured something I love. Sometimes it doesn’t happen until I am reviewing the image large on my computer. Then I discover that it is far more interesting than I thought at the time I took it. Both are joyous occurrences.

    More often than not, I find I have well composed, well exposed pictures of – nothing much. I look at them later and say “yeah, it was an interesting scene and it’s an OK picture, but it doesn’t grab me.” Usually I think it is because I did not feel strongly about the subject or scene. I didn’t fall in love with it.

    If I don’t feel passion for the image, how can I expect you to when you view it? It is pretty obvious to me which ones really grab me. I think you can perceive it, too.

    Over-planning

    At the opposite end I see some photographers occasionally get trapped by over planning. Conventional wisdom from many renowned photographers is that any photo trip or outing should be planned out in great detail. They will research a location extensively, looking at pictures from other photographers to try to find the “best” places and positions and angles and times and seasons. In addition, they will use tools like The Photographer’s Ephemeris to select the exact time and day and location to get the exact sunrise/sunset/moonrise/ etc. shot they want. And they may book an outing with a workshop or guide to help with the logistics and transportation.

    Is there anything wrong with doing it this way? Absolutely not, if that is the way you work. Different personality types need to approach things in different ways. Do what works for you, but don’t get into a mental trap.

    One of the traps I see is that we tend to get so invested in the preparation for the shot that we have to take it. We spent a lot of time and money to get to that point. It becomes a quest. It has artificially become so important that we have to take the pictures to validate and justify the trip.

    But what happens when you get there and the weather is “bad”? Bad being not what you planned for. Maybe you don’t like the workshop leader or structure. Worst, what do you do when you get there after all the planning and expense, look at the scene, and feel “meh”?

    Of course you take the pictures. You have to. But if you’re honest, they may not make your portfolio set you are excited to show people. There was just no life there. You can check off that you got the iconic shot, but maybe it ends up not being very important.

    Having our expectations too high can lead to disappointment.

    Anti-planning?

    You can guess from what I’ve written that detailed planning is not for me. I am almost an anti-planner. I tend to come at things the opposite way. Going to iconic locations and fighting for a tripod location and taking the exact same image 10,000 other photographers have taken just in the last month is not a motivation for me.

    Yes, the scene is beautiful. Yes, it is probably salable because it is the type of image people like to have on their wall. Economically it is foolish to not get this image and pander to the crowd.

    But for me, even though I think the scene is beautiful, I probably will not feel great passion for it. How can I distinguish myself from the thousands of other photographers shooting the same things? How can I tell my story or share my feelings?

    In love

    Back to the original statement of this article, I believe I have to fall in love with my images. If I am going to show you something I have made, it has to be much more than good. It has to have a passion you can sense. How can I bring you art you want unless I feel strongly about it?

    Thoreau said “A man has not seen a thing who has not felt it.” The famous photographer John Sexton said “Too often we attempt to force a photograph out of a situation rather than allow the situation to speak to us.”

    I am guilty at times of trying to force images to be there when I’m not actually listening and feeling. I recognize it. It is painfully obvious when I am reviewing them in Lightroom that I have a bunch of well executed pictures that mean nothing to me. Trashing them is the best thing to do. And use it as a reminder to follow the passion more than the light. If I don’t have a sense of wonder and passion for the image that is a good sign that it probably didn’t work.

    “Follow your passion” is not always good advice in life – you have to do a lot of things you don’t like. But in art it is great advice. It may not be the clear path to fame and fortune, but you will feel good about what you create. And your viewers can tell. Love your work.

    This example

    I have used this image at the top before. It is a good illustration of my point here, though.

    I love this image. I could stare at it for a long time. It speaks to me at a level I can’t even describe. The rich color, the organic flow, the streaks of movement over time, the standing wave shapes, the minimalist simplicity all move me.

    This as shown here is almost straight out of the camera. It is what I shot. Yes, it has been cropped square and had some minor tone corrections, but this is what I discovered and jumped on. The color and the time effects of the flow are as shot. I liked it as seen through the viewfinder. I loved it after I saw it large on the computer.

    It is one of the few pictures I have hanging on my wall at home.

  • Photoshopped

    Photoshopped

    It may be said as an insult. It may be used to shame the photographer as “not a purist”. But should it be? What is wrong with an image being Photoshopped?

    History

    Photography began as a medium of realism. It is said that Impressionist painting (Monet, vanGogh, etc) was a reaction to the realism of photography. They took their art is a direction photography could not challenge – at the time.

    Have you ever thought of traditional painting changing its direction because of photography?

    The development of Impressionism can be considered partly as a reaction by artists to the challenge presented by photography, which seemed to devalue the artist’s skill in reproducing reality. Both portrait and landscape paintings were deemed somewhat deficient and lacking in truth as photography “produced lifelike images much more efficiently and reliably”.[31]

    Because of the history, and the fact that everything the lens sees is recorded in detail, people tend to have an expectation that a photograph is “real”. A picture can’t lie.

    Not only is this wrong in so many ways, but it is no longer a realistic expectation of photography.

    Common practice

    All photographs are altered from what the sensor recorded. Even if you just take that picture you snapped on your phone and post it to social media, it was altered a lot before you ever saw it. All sorts of distortion corrections, color enhancements, gamma correction and noise reduction was done by the phone. Their algorithms are very good at making the picture look like what you expected to see. It is not the same as the phone recorded.

    All images you see in prints or any media are altered – Photoshopped. Some massively. Some just minor color correction and tone enhancements. I would never insult you by showing you an unprocessed picture. Unless it was to make a point about the kind of processing I do.

    Even to do black & white these days requires a lot of image processing.

    Did you know that even movies are “Photoshopped”? An obvious example is CGI. That stands for computer generated imagery. It proudly states that a lot of what you are seeing is artificially created. And we love it in big action movies.

    Nearly all movies are digitally recorded now . All are processed and retouched frame by frame in addition to CGI enhancements. The overall color you see is even completely controlled. They call it color grading. The entire look and shading of each scene is digitally processed to set the mood the director wants.

    Bad Photoshopping

    One thing I will join people in denouncing is bad Photoshopping. Photoshop is a very complex program to master. It can take years – and they are constantly changing it. But even so, we are artists. We have no excuse for not mastering our tools.

    Not knowing how to use the tools to accomplish our vision is like a painter not knowing how to use a brush or a metal sculptor not knowing how to weld. Just using some simple sliders to make the color of an image wonky is not much of an artistic statement.

    Yet I have heard well-known professionals almost brag about their limited knowledge of Photoshop. But the reality is that they know enough to do what they want. The exception is Jay Maisel. Jay is one of the greats who I admire. He brags that he does not even have Photoshop on his computer. That is probably true, but he has full time assistants who do have it and can make a picture look like what he tells them he wants. So, a slight exaggeration for dramatic effect.

    For the others, though, who really do not know Photoshop well: spend time learning it. It will reward you by making you more efficient and it will open up new artistic possibilities for you.

    Artistic expression

    My work is called “fine art”. I don’t like the term, but we are stuck with it. Fine art, among other things, means it is not literal or representational. I feel free to bend and even break pixels to any degree I want to bring you the art I see.

    I guarantee that any image of mine you see has been processed in Lightroom Classic and maybe Photoshop. Both great tools are well capable of altering the reality of the original frame. And I do alter them.

    It can range from basic color and tone correction to removing distracting elements to compositing several images together to create something new. Anything is fair game. The more adapt at my tools I get, the more I am able to use them to help me change my vision. It is circular: what we find out we can do helps us to see new things to do.

    Accept it

    I accepted it a long time ago. My Photoshopping goes back to about version 5 or 6. In the beginning, I was mostly just doing minor corrections on my very realistic landscapes. I have fond memories of the controversy in the camera club I was in at the time when I won best of show with the first digitally manipulated image ever submitted to them.

    Since then I keep widening my vision and perspective. Realism was so deeply ingrained in me that I have had to work at giving myself permission to let my imagination go free.

    I’m not where I want to be yet, but I take a much more liberal view of what I can do in an image. Still, I am my own limitation.

    If you are seeking “truth” in images, be careful. But if it is important to you, do some research to find out if the image has been manipulated materially. It has been manipulated. but that doesn’t mean content has been added or deleted.

    Finding truth is rare in our world. When you look at an image, assume it is art, not truth. At least, that will be true for my work. I may bring truth, but that does not mean it is realism. My images are photoshopped.

    The future

    In the 19th century, painting was mostly about realism. Then photography came along and took over realism. So painting moved to Impressionism and modernism and abstraction. Now digital art is perfectly capable of creating any abstract or impressionist images we desire. Where will painting go next to separate themselves?