Metering by Eye

Light is the basic element of photography, just as sound is that of music. A good photographer should be as familiar with light as the good musician is with notes and scales. Photography is, at its core, based on a very simple principle. An image of the world is captured by allowing a certain amount of light to fall on a piece of photosensitive material. Whether the photosensitive material in question is a silicon chip, silver film, glass plate or salted paper, this elegant little concept holds. Whether or not the light is shaped by the latest cutting edge in glass and coating technology, an old brass lens or indeed a humble pinhole, the same principles apply. The crucial questions of how much light reaches the photosensitive material and in what ways that amount may be controlled go to the very essence of photographic technique – the determination of exposure.

“Reading the light” or “metering by eye” can be easily mastered with a little practice, yet most photographers leave this central photographic decision almost entirely to their camera. Of course, camera meters work, but it helps to know precisely how a camera sets exposure and what a particular process' limitations are – in other words it is useful to know when to disagree with the camera and to take control of exposure decisions. But many new photographers think metering is some unfathomable mystical art best left to eccentric geniuses and pieces of silicon. Camera companies have done their bit towards obfuscating the issue by bragging about the wonders of “35 area evaluated metering,” “3D matrix metering,” “40 segment multi pattern metering” and such. These modes can indeed be powerful and useful tools for the right job but they don't yet supplant the intelligent photographer's brain. So let's try to lay out a practical approach to metering by eye, or being able to set the correct exposure without the help of a light meter. I shall assume that the reader is familiar with the basics of photographic exposure and can use a light meter efficiently (although I'll deal with those basic issues in a later article).

LV and EV: Ways to Think About Light
For the purposes of figuring out incident light levels we will try to think in something called LV or “light values.” LVs are a sequence of numbers representing intensity of light. Each number is double the previous one and half the next one – i.e. they are on a logarithmic scale. Thus LV 11 denotes twice the amount of light than LV 10 and only half the amount of light compared to LV 12. This might remind you of the f-stop scale and that is exactly what we are going to think of the LV scale as. Henceforth we will think of LV values in terms of “stops of light” - thus we could say LV 10 is two stops below LV 12 and so forth.

To avoid confusion, we might briefly mention EV here (although you won't need it for our purposes of metering by eye). EV, or exposure value, which you will see on many light meters, refers to particular exposure levels which can be achieved by certain aperture shutter combinations. For example EV 15 can be 1/100 at f16 which is the equivalent of 1/200 at f11 or 1/400 at f8 and so forth. All of these shutter-aperture combinations result in the same level of exposure (although the depth of field will differ, of course) and are designated by EV 15. If you notice we have not yet taken account of the sensitivity of the film or sensor – i.e. the ISO value which is the other major factor that influences exposure. So naturally as ISO varies, the same EV shutter aperture combination will produce different levels of final exposure. So while for bright sunlight EV 15 will the correct exposure for ISO 100, the same exposure will be produced by EV 16 for ISO 200 or EV 13 for ISO 25 etc. Key point: EV numbers change with changing ISO.

LV numbers, on the other hand refer simply to the level of light and don't take into account the specifics of photographic exposure. Thus, they provide a better and more uniform way to think about light levels. If you familiarize yourself with the LV scale you can see a certain amount of light and immediately think of its LV value whether or not you have ISO 1600 or ISO 100 set on your camera. This separation of light levels and specific exposure factors like ISO-aperture-shutter has its advantages.

How do LV and EV numbers relate (or, another technicality you might want to ignore)? Well, they are exactly the same for ISO 100. But if the ISO changes to anything else, EV numbers naturally change while LV remains constant. If you figure the ISO in terms of an offset from 100 in number of stops then you can get EV by adding that number to the LV value: EV=LV+offset. A couple of examples will make this clear. Let's say you have ISO 400 film – that's two stops more sensitive than 100. So the EV value would be LV+2. If it's bright sun, the LV value is 15 and the EV value is 17. For ISO 50, the offset will be -1. So the corresponding EV value would be 15+(-1)=14. If this seems too complicated, ignore it – in fact, totally ignore EV for the moment and think of light only in terms of LV.

Recognizing LV values
Bright sunlight – that is, LV 15 - and that is our first cornerstone. Silly though it might seem, familiarize yourself with bright sunlit conditions - how intense is it, what kind of shadows does it cast? We will learn to think of other light levels in terms of how they differ in intensity from bright sun. And once you have mastered LV 15, think of everything else in terms of how many stops of light darker (in very few cases brighter) it is compared to bright sun. The best way to master this is to walk around for a couple of days with a light meter or even a camera with a meter. Whenever you see a new light level – take a guess how many stops below bright sun it would be and cross-check against your meter. Cloudy? That's maybe 2 stops below (LV 13). You will be surprised how fast this can be picked up.

Once you know your bright sun, there is another light level that I recommend familiarizing yourself with thoroughly – that of a moderately well-lit indoor setting. This is definitely harder to define in any concrete manner, so a light meter will definitely help. Look for LV 5 – or 10 stops below bright sun. It should be a about the light level of a moderate sized room lit with a 100 watt bulb. Once you find it, familiarize yourself with it fully, because it is much easier to think of night exposures as offsets from this instead of from bright sunlight. A brightly lit hall? A stop above – so EV 6. A lamplit street? Two stops below – so EV 3.

Converting LV Values to Exposure Settings
You may know the “sunny 16 rule” which says that in bright sun the correct exposure is 1/ISO value. So if you have ISO 250 film you'd set f16 at 1/250. What happens when your light is, say, four stops below bright sun – or EV 11. You can simply take the f16 at 1/250 combination and “open up” four stops. This can mean opening up the aperture or slowing down the shutter or a combination of both. So open up to f4 and keep 1/250; or alternatively keep f16 and slow your shutter to 1/15; or open aperture two stops to f8 and shutter two stops to 1/60. The combinations don't matter – as long as you “open up” the requisite number of stops. So, always start with the ISO value of your film/sensor for your shutter speed and f16 and then calculate how much you want to open up each. This implies of course that you are totally familiar with the aperture and shutter speed scales. That f2.8 is five stops from f16 or that 1/8 is 5 stops from 1/250 should be second nature – as much a reflex as scales under a pianist's finger. Fortunately, you'll find mastering this set of apertures and shutter speeds - if you don't already know them well - is much easier than learning to play the piano! Once this is accomplished, setting exposures for any LV will not be a problem. Let's say you're shooting in a relatively well lit restaurant that you think is LV 6. You have ISO 500 set on your digital camera and a fast f1.4 lens. However, you would like as much DOF as possible but don't want to handhold below 1/30. You need a total of 9 stops below bright sun. So set shutter to 1/30. That's 4 stops. The other 5 stops you'll need to get from aperture – so set it to f2.8 and presto!

In the age of advanced camera meters this might seem tedious and way too complicated at first. But just like synth-loops haven't put good drummers out of a job yet, the good photographer will know exactly when the meter can handle a scene and when to take control. I'll end with an ordinary example. This shot was made very hastily indeed. I saw these cool looking guys walking unconsciously in formation lost in the latest football news and had only a few quick seconds to frame, focus, set exposure and shoot. This is exactly the kind of scene where you want the quick automation of a modern intelligent camera meter, right? Wrong! Not because the meter isn't competent – but because it simply can't read my mind. There's more than one way to shoot this scene, surely. What if I wanted to have the street perfectly exposed for bright sun and have the guys looking like cool silhouettes? Most old camera meters would be “fooled” by the bright background and do just that. But it's not a question of getting fooled – it's about knowing the intention of the photographer. No matter what the camera companies tell us – there is not just one "correct exposure" of a scene. The exposure depends on the photographer's intended interpretation – just like this scene would work with at least three or four different exposure levels and produce four different interpretations. So unless they make a camera that plugs into a USB jack behind my ear to pick up what my brain is thinking, the camera meter simply doesn't know what effect I am going for. So even if you have a fancy meter, knowing the ins and outs of exposure will let you tell it just what to do (by setting the amount of compensation you want, for example). For me in this scene it involved a couple of quick and simple steps. I wanted to expose for the guys' faces but not totally blow out the background. I know that in bright sun, full shade is almost four stops less bright. So I decided to go for 3 stops below LV 15 (underexpose their faces by a stop at most but hold as much detail as possible in the background). So with ISO 250 film, I set my aperture to f8 and shutter to 1/125 – three stops – click!

Van Dyke Prints: An Overview

For a little background to these overviews, see here.

History: Introduced in 1889 by Arndt and Troos, the Van Dyke print is part of a group of iron based processes which draw on Sir John Herschel's work on the Argentotype silver-iron process developed in 1842.

Negatives: A density range of about 1.5 is suitable.

Sensitizer: Part A: 9gms ferric ammonium citrate (green) + 35ml water
Part B: 1.5gms of tartaric acid + 35ml water
Part C: 12gms silver nitrate + 35ml water
In moderate light mix A, B and C (in that order) and age for a few days before use. The solution keeps well for about a year if kept in a cool, dark place. At times, owing to trace chemicals in various supplies of ferric ammonium citrate, the sensitizer may develop a muddy precipitate after about 2/3 of solution C is mixed. This can be allowed to settle and the clear sensitizer on top used, or adding about 2.5 gms more of tartaric acid can also dissolve the precipitate. The additional tartaric acid results in a fainter or no print-out image, but the developed image looks fine.

Contrast control: Contrast control can be achieved by (a) using ferric citrate in varying proportions in Part A of the sensitizer, (b) by adding about 10 drops of a 10% solution of potassium or ammonium dichromate to 500ml of the second bath during washing. (c) printing in diffused light (with perhaps a burst of direct light at the end) also subtly affects contrast. Refer to Christopher James' book for details.

Coating the paper: Use a glass rod or hake brush to coat the paper. Once the sensitizer sets, further coats can show up as streaks, so quick coating is helpful.

Printing: Print until the image appears about a stop darker than you want the final result.

Processing: (1) Wash in distilled water or tap water with a pinch of citric acid added for 5 mins. (2)Wash in running water for two mins. (Can be toned after this point). (3) Fix in 3% sodium thiosulfate solution with .2% sodium carbonate (washing soda) for about a minute, (4) followed by a final wash in running water for 30 minutes. Hang to dry. Ironing the print with a hot iron can increase the contrast slightly and change the color.

Albumen Prints: An Overview

For a little background to these overviews, see here.

History: First introduced by Louis-Desiree Blanquart-Evrard in 1850, albumen printing was the dominant photographic process for most of the second half of the nineteenth century.

Negatives: A density range of 2.0 to 2.5 is good.

Preparing the albumen: 500ml of egg whites (no yolk or white stringy bits) + 1ml glacial acetic acid + 15gm ammonium chloride + 15ml distilled water. Stir briskly until it turns into a froth. Cover container and refrigerate for 24 hrs. Remove the froth on the top and filter the liquid through cheesecloth. Age in refrigerator for a week or more.

Coating the paper: Coat by floating for 3 mins and hang to dry. To double coat, the albumen needs to be hardened. This can be done by steaming, heating to about 150F with a hot iron under a protective board, or dipping in a 500ml 70% isopropyl alcohol + 15gm ammonium chloride bath.

Sensitizing the paper: Either float, brush or use glass rod to coat with 12% silver nitrate solution under safelight. Sensitized paper does not keep well. Floating works best but results in albumen contaminating the sensitizer solution. To maintain the silver nitrate solution over a long time, add 1.5 gm kaolin per 100ml of solution. The kaolin is insoluble powder that absorbs the impurities and settles at the bottom. After every use, shake up the kaolin and let it settle overnight. Decant or siphon off clear solution before next use. Replenish the amount of solution used up with a 24% solution of silver nitrate.

Exposure: Expose until the shadows begin to bronze (maximum density) or for thinner negatives, the highlights are 1 to 1.5 stops darker than desired. Direct sun gives less contrast than diffused light.

Processing: (1) Wash 5-10mins until there is no milkiness in the running water. (Can be toned at this point). (2) Fix in 75gm sodium thiosulfate + 1gm sodium carbonate (washing soda) + 500ml water. Two fixing baths of 4mins each is recommended. (3) Immerse in 1% sodium sulfite solution for 3mins as a hypo clearing bath. (4) Wash for 30mins. Squeegee and hang to dry.

Cyanotype: An Overview

As I explore a photographic process, I will post brief summaries of its essential technical elements. These summaries are not meant to be comprehensive or to substitute for books that deal in-depth with these processes. They are more field notes for myself and might be useful for a quick lookup while working with these processes. Remember that many of these alternative processes have been around for a century and a half and more and they have evolved considerably over that time. Remember, too, that these processes were not originally meant to be used with silver or even digitally printed negatives as most modern practitioners of alternative photo processes do. There are endless variations of formulas and techniques rather than one simple "right" method as my quick overview might imply to the superficial observer. But hopefully these summaries will serve as a quick reference or encourage you to read and explore further.

History: The Cyanotype was first described by Sir John Herschel in 1842. Numerous variations on the original formula are available.

Negatives: Generally a density range of about 1.35-1.4 is okay. That is, many negatives meant for ordinary darkroom printing with diffusion enlargers can be used. I find slightly contrastier negatives with a range of about 1.5- to be more suitable when using vinegar instead of water as the developer.

Sensitizer: Solution A: 20% ferric ammonium citrate (green) solution
Solution B: 8% potassium ferricyanide solution
Store both solutions in separate bottles and mix 1:1 just before use. Solutions will keep indefinitely in sealed dark bottles. Bacteria that might grow on solution A can be filtered off.

Coating the Paper: Any non-buffered paper can be used with gelatin sizing if necessary. Alkaline environments will degrade Cyanotypes. Coat evenly with brush or glass rod under low tungsten light. Can be air dried or dried with mild heat.

Printing: Printing times can be fairly long. Check the highlights by opening the split back to see if they are a shade or two darker than you want in the print. They will lighten considerably in the wash. The shadows are not good indicators as they might begin to reverse during the printing out process.

Processing: Cyanotypes can be developed using water. But white vinegar gives slightly more midtone contrast, about a stop and a half more dynamic range and a sharper print. But vinegar tends to tint the highlights light blue instead of pure white. I have found a 1:1 mixture of white vinegar and distilled water to give the best balance between retaining highlights and a longer tonal range. Develop by agitating in a tray for 45 secs to one minute and then put in a running water wash for 5 minutes. Hang to dry. A 0.3% bath of hydrogen peroxide (1+10 sol of commonly available 3% hydrogen peroxide solution and water) just before the final wash will oxidize the print to a deep blue. This is not necessary as the print will slowly oxidize in the air as it dries, but the peroxide bath lets you see the final color at once.

Toning: Tea or coffee or tannic acid can be used to tone cyanotypes. Bleaching with a solution of one tablespoon of sodium carbonate (washing soda) per liter of water solution before toning is said to reduce staining effects but I have not yet found a satisfactory method to produce repeatable results while toning cyanotypes.

The Keepers of Light: Book Review

This book takes its subtitle - "A History and Working Guide to Early Photographic Processes" - quite seriously. It is as much a history of early photography as it is a practical guide to early processes. So, while most handbooks for these processes have a bit of history included for 'background' as a matter of course, Crawford dedicates the major chunk of the book to a detailed, sustained and quite insightful history of early photography. The practical guide to these processes is quite competent but it is almost an afterthought after the exhilarating tour-de-force of the first section of the book on the development of photography from its earliest days to well into the age of the silver gelatin print in the first half of the twentieth century.

I have always found most histories of photography to be quite tedious. They usually read like a long list of dates and developments and brief backgrounds of the persons associated with them. This approach is akin to the older sort of history as a narrative of the rise and fall of kingdoms and rulers - a history based around personalities and a more or less linear notion of progress. But Crawford takes a leaf out of newer historians who write social history not as a linear narrative but as a 'genealogy' of inter-related strands perpetually interacting with each other - 'history from below.' Of course, he isn't writing with the grand developments within academic historiography in mind, but his approach makes this a very apt comparison.

The Keepers of Light lays out the evolution of what Crawford calls the 'syntax' of photography. The first chapter uses the examples of traditional printmaking and painting very effectively to lay out what exactly constitutes a 'syntax' for a visual medium. The parallels to modern theories of linguistics and semiotics are unavoidable and Crawford uses them very effectively to illustrate his point that every visual medium has a basic 'vocabulary' and 'ordering pattern' which combine to produce a coherent 'meaning' for the observer. This can be constituted of the most basic elements like the direction and thickness of strokes in an etching or the overall formal and technical limits of a medium. And the syntax of a medium can emphasize particular elements like form, texture, tone etc at the cost of others. Crawford argues that even though photography is sometimes seen to be a medium without a syntax - a process that merely reflects the world and is therefore in a direct and 'natural' correspondence with it - in fact each particular photographic process is strictly governed by a syntax. Every detail of the process - the tone, the detail, the reproducibility, even the duration of exposure required or things like generic conventions contribute towards the syntax. Together they define the limits and possibilities of the medium, how it produces the photographic artifact and how we, as the audience, make sense of that artifact. If anything, the photographic process is so intimately tied up with technology that the limits and possibilities of the syntax must be confronted every step of the way.

Thus Crawford sets out to write a history of early photography not as a history of linear events, but as one of the evolution of the photographic syntax. Part I of the book, divided into 12 chapters, traces this evolution in terms of changing conventions, demands and technical challenges that forced nineteenth century photography to constantly develop and evolve. The result is a breathtaking history which makes the twentieth century or even the fast pace of recent change with the emergence of digital seem quite tame by comparison. In doing so, it returns the reader to the sense of awestruck wonder that the practitioners of photography or its first audiences and consumers might have felt. To capture a veritable image of the world on a sheet of paper - as if not made by man but by Nature herself - this is something the magical, awesome quality of which we have lost sight of. We with our oh-so-sophisticated cameras, 51 point autofocus and our MTF charts - even those of us who think of ourselves as 'traditionalists', use older film cameras and obsess over the zone system and sharpness. All of this is mere trifle compared to the wonder - the very sorcery - of the crude image of Paris rooftops on Niepce's bitumen covered glass. And isn't that why so many try alternative processes? To discover a hint of that magic, the discovery of the new world, the first step on the moon? It is akin to the the jaded business traveler ticking off his air miles discovering the struggle that went into man's conquest of flight - from the myth of Icarus to the Wright brothers.

And the syntax is not merely a thing-in-itself - a mere description of the technical boundaries of a process. It lives in and interacts with the world in a way an unilinear perception of 'progress' cannot grasp. Thus the Daguerrotype reigned supreme since its introduction in 1839 for a couple of decades. Technically it was capable of producing results that would satisfy the zone system or sharpness junkie of more than a century later. But there were both socio-cultural and technical demands that its syntax couldn't satisfy. Crawford traces how the more painterly rendering of the Calotype and other processes proved more pleasing to an age for which photography had not been established as a completely unique and independent medium and the reproducibility of negative images proved too strong a technical demand to resist. So the syntax moved on, it evolved, it responded to demands.

It is in conceiving of the history of photography as the history of this dialog between form and content, between demand and response that Crawford's approach is so refreshing and unique. It is full of insightful detail accompanied by vignettes and bits of humor that are all the more charming because they do not quite fit with Crawford's somber academic style. Consider for example, the following revelation: "Subjects in early daguerrotypes frequently sit with one hand supporting the chin. They look like deep thinkers: They were actually concentrating on not moving their heads" (9). Similarly delightful are his observations on the limitations imposed by technique and form on content: for example, the depopulated cityscapes in early long-exposure Calotypes, or how the exposure limitations of certain processes dictated the look of many early street photos. Amusing and astonishing, too, are vignettes about the crisis in egg supply when factories were consuming 60,000 or more eggs per day to coat albumen paper or the fact that there were studios in the 1860s churning out over 1,000 copies from a negative per day! All of this leads to a history of photography down to the period of dominance of the silver gelatin print that is truly novel in approach and eye-opening in detail.

I have spent most of this 'review' on Part I of the book. This isn't unintentional because that is the part I found most compelling. The other two parts constitute a practical guide to some of the major processes and techniques of preservation. They are chock-full of detail and great for anyone wanting to try it out, but there are relatively few illustrations and some of the materials and sources from this 1979 book have obviously fallen out of date. For a pure practical guide, perhaps more recent books like Barnier's or James' might be better, or even one of the many internet sources for quick summaries of processes. But Crawford's basic introduction to sensitometry (while a little advanced in that it tends to assume familiarity with conventional darkroom sensitometry) and technique is very helpful. In other words, buy another book if you want merely a DIY guide, but definitely read this book if you want a perspective that will change the way you look at photography - not only its past, but even its present.

Crawford, William. The Keepers of Light: A History and Working Guide to Early Photographic Processes. New York: Morgan & Morgan, 1979.

Using a DSLR as a Shutter-Tester

What good is a DSLR if you can't test the shutter of your Holga with it? Ok, I'm kidding, but there is a fairly simple way to use a DSLR as a shutter speed tester for any lens that has a leaf shutter. In fact, with a little care, this method can be used to test practically any shutter. Don't expect pinpoint accuracy or rush to put your lab equipment on eBay, but this method should be accurate to within at least a third of a stop - certainly good enough for average everyday use.

Think for a moment what a shutter does. It is simply a way to block the path of light falling on the film/sensor and then to remove that blockage for a certain known amount of time to let light fall on the film/sensor. It's a pretty simple concept really - a mechanized and repeatable version of the old hat-on-lens technique. Problem is, shutter speeds go off - they slow down, they speed up and do all sorts of funny things. Often, as in the case of mechanical marvels like the Holga, they are simply unknown, or vary from camera to camera. But if there is one good thing to be said of modern electronically controlled shutters in DSLRs and or other electronic thingamagigs, it is that they are remarkably accurate and consistent. So let's get about measuring a mechanical shutter by directly comparing it to the known shutter speeds of a DSLR.

Our first task would be to mount whatever lens/camera/shutter we want to test in front of a DSLR. Now, we don't need to focus anything or permanently mount anything. We just need to make sure that we can hold our shutter in front of the DSLR in such a way that when the shutter is closed (and the DSLR's shutter is open), no light reaches the sensor. We also, however, need to make sure that nothing sticks into the body of the DSLR so that we don't end up damaging the moving mirror. This can be done in a few ways, but the easiest for me was to use a hollow extension tube (or set of tubes) used for macro photography. I used a Nikon PK-13, mounted a BR-2a reversing ring on it and then used a simple hollow black tube that is available for less than $5 at camerafilters.com. You can use whatever you have handy - the basic idea is to provide a reasonable bit of distance between the shutter and the DSLR's body. Once done, the setup should resemble the picture on the right (I used a film body in the pictures, because I was using the digital body to make the pictures).

Now, point the whole setup towards something reasonably bright, uniform in color and preferably near middle gray in tone - a wall, the sidewalk, distant trees and the sky all work well. Nothing needs to be in focus - in fact, we want things as blurry as possible. Now the optical path has two shutters obstructing the light - the shutter to be tested, and the focal plane shutter of the DSLR. Light will reach the sensor only when both shutters are open. If we hold open either shutter in bulb mode, the other shutter's speed will be the sole determinant of the amount of light reaching the sensor. Quickly test that the optical path is truly light-tight by keeping the shutter to be tested closed and holding the DSLR's shutter open for a few seconds. If no stray light reaches the sensor, you will get a spike at the far left of the histogram as in the first histogram of the screen-capture to the right.

So now, let's put the DSLR on bulb (having a locking remote release is helpful) and fire the shutter to be tested. If you look at the resulting histogram you will see a sharp localized spike at one point. Adjust the ISO (if the lens you are testing has an aperture iris, you can also adjust that - just make sure nothing changes throughout the test) so that the spike is somewhere along the middle like the second histogram in the illustration and we are all set. Note the position of this histogram and now put the shutter on bulb and make a series of exposures with the DSLR shutter around the speed you are testing. So if you are testing to see whether the speed that says 1/100 on your shutter is accurate, then do the following:

• Make the first exposure with the DSLR on bulb and with the shutter you are testing fired at the 1/100 setting.
• Now, put the shutter being tested on bulb and make exposures with the DSLR at 1/200, 1/160, 1/125, 1/100, 1/80, 1/60, 1/50.

Each exposure is a third of a stop more than the previous one. If you observe the histogram, you will notice that the spike gradually travels to the right as you increase exposure. Try to pick out the one that has the spike closest to the one in the first frame - that is your shutter speed. Simple.

A word about RGB histograms. You don't need to bother with them for the test. If your subject is middle gray and your white balance is set correctly, your RGB spikes will be more-or-less at the same point, otherwise just use any of the channels or the combined histogram. In this test we are just comparing exposure times by comparing the amounts of light let in by either shutter, so as long as every other factor is consistent between those two exposures, we should do fine.

So that is it. Once you try it out, it's a pretty simple test and you should be all set to make precise exposures on Velvia with your Holga. Have fun!

Alternative Photographic Processes: A Bibliography

Here is a general bibliography on alternative photographic processes. I will keep adding to it as I come upon more resources and, over time, will put up more detailed reviews of titles I get to know well enough. If you have more suggestions to add to the list, please let me know.

• Anderson, Christina. Alternative Processes Condensed: A Manual of Gum Bichromate and Other Contact Printing Processes. Self-published.
• Arentz, Dick. Platinum and Palladium Printing. St. Louis: Focal Press, 1999.
  
• Barnier, John. Coming into Focus: A Step-by-Step Guide to Alternative Photographic Printing Processes. San Francisco: Chronicle Books, 2000.
• Blacklow, Laura. New Dimensions in Photo Processes: A Step by Step Manual for Alternative Techniques. 4th Edition. St. Louis: Focal Press, 2007.
• Burkholder, Dan. Making Digital Negatives for Contact Printing. Bladed Iris Press, 1999.
  
• Coe, Brian. A Guide to Early Photographic Processes. London: Victoria and Albert Museum, 1984.
• Crawford, William. The Keepers of Light: A History and Working Guide to Early Photographic Processes. New York: Morgan & Morgan, 1979. [REVIEW]
  
• Enfield, Jill. Photo Imaging: A Complete Visual Guide to Alternative Techniques and Processes. New York: Amphoto Books, 2002.
• Eshbaugh, Mark L. Alternative Photography Processes: A Worker's Guide. Self-Published.
• Farber, Richard. Historic Photographic Processes. New York: Allworth Press, 1998.
• Greene, Alan. Primitive Photography: A Guide to Making Cameras, Lenses and Calotypes. St. Louis: Focal Press, 2001.
• Hewitt, Barbara. Blueprints on Fabric: Innovative uses for Cyanotype. Pub Overstock Unlimited Inc, 1995.
• Hinkel, Brad & Ron Reeder. Digital Negatives: Using Photoshop to Create Digital Negatives for Silver and Alternative Process Printing. St. Louis: Focal Press, 2006.
  
• James, Christopher. The Book of Alternative Photographic Processes. 2nd Ed. Clifton Park, NY: Delmar Cengage Learning, 2008.
• Keuren, Sarah Van. A Non-Silver Manual: Cyanotype, Vandyke Brown, Palladium & Gum Bichromate with Instructions for Making Light-Resists Including Pinhole Photography. 3rd Edition. Self-Published, 2004.
• Koenig, Karl. Gumoil Photographic Printing. St. Louis: Focal Press, 1999.
  
• Oelbaum, Zeva. The Natural World in Cyanotype Photos. Rizzoli International Publications, 2002.
• Rexer, Lyle. Photography's Antiquarian Avant-Garde: The New Wave in Old Processes. Harvey N. Abrams: 2002.
• Sanderson, Andrew. Handcolouring and Alternative Darkroom Processes. Rotovision: 2002.
  
• Scopick, David. The Gum Bichromate Book: Non-Silver Methods for Photographic Printmaking. St. Louis: Focal Press, 1991.
• Spence, Ray & Tony Worobiec. Beyond Monochrome: A Fine Art Printing Workshop. Voyageur Press, 2000.
  
• Stevens, Dick. Making Kallitypes: A Definitive Guide. St. Louis: Focal Press, 1993.
  
• Webb, Randall. Spirits of Salts: A Working Guide to Old Photographic Processes. London: Argentum, 1999.
• Ware, Mike. Cyanotype: The History, Science and Art of Photographic Printing in Prussian Blue. London: Science Museum, 1999.
• Watkins, Derek. Bromoil: A Foundation Course. Photographers' Institute Press, 2006.
  
• Webb, Randall and Martin Reed. Alternative Photographic Processes: A Working Guide for Image Makers. Silver Pixel Press, 2000.

Web Resources:

• AlternativePhotography.com
• Unblinking Eye
• Mike Ware Alternative Photography
  
• Tom Ferguson's Tutorials