ISO, Grain, Transparency vs. Negative, Specialty Films

Film - A History Of Its Beginnings
It's difficult to imagine a world without photography. Photographs changed the world in ways that we can barely imagine. We can now literally see things that happen all the way across the world without ever leaving our home. We can communicate visually with people who don't even speak our language. That world without photography existed just 165 years ago. Before that, people relied on paintings and verbal descriptions, which were entirely dependent on conscious or subconscious alterations interjected by the people that used these methods to communicate.

Prior to the creation of a successful photographic process, man was fascinated with the idea of creating a photograph. Leonardo DaVinci made drawings of plans for a basic camera as far back as 1519, but there was no way to actually capture images that would last permanently using this tool. Over the next several hundred years, many scientists noticed that forms of silver, when exposed to light, would darken. That basic camera, called a Camera Obscura, could be used to actually create images using this silver solution, but there was no way to make the image permanent.

In 1827, a man by the name of Nipce (pronounced Nee-ps) found a way to make a light-sensitive silver solution harden. It required an exposure time of eight hours or more, but this was actually the very first successful photograph. Nipce called these Heliographs. He then went into a partnership with a man name Daguerre. Nipce died shortly thereafter, but Daguerre kept working on the photographic process and found a way to decrease exposure time to less than a half hour, and also a way to use salt to make the images permanent. These images formed positive 'prints' on metal plates. Daguerre called his images Daguerreotypes and is largely credited today with discovering photography.

This entire process caused QUITE a stir. (Daguerre's wife was about the only person who was happy with his results, because she'd spent the last several years thinking her husband was losing his mind working night and day on this project.) People had never seen such images before with such detail and found it kind of disturbing. Many called daguerreotypes blasphemy and the work of the devil. Then there were the painters and artists who were terrified that photography would overtake what they did for a living and feared that they would have to find new professions. I find that last note of particular interest because today I hear the same sort of thing from others in my profession who have spent the last thirty or forty years shooting film and are now daunted by digital photography and it's ease of use contributing to the number of photographers growing by leaps and bounds.

I have seen daguerreotypes and they are truly beautiful and amazing, though aside from the end process of capturing an image made of light and making it permanent, the process is very different from any current photographic technique used today. Further advancements that got us to the point where we are today were: the ability to transfer these permanent images to paper rather than metal plates; the ability to copy these images without having to re-take the picture; the invention of celluloid film - then the invention of COLOR celluloid film; motion picture photography and digital photography - the latest step in the journey of advancements.

Okay, But How Does Film Work?

So now we sort of have a history of where photography came from, but how does film actually work? Let's talk about light for a minute.

There's something called the electromagnetic spectrum. It's composed of everything from microwaves to radio waves and ultraviolet waves to infrared waves. Somewhere in the middle of all of that is a tiny little section of light waves that the human eye can see and interpret into different colors from red to yellow to blue.

Light is really weird stuff. According to the physics books it's not REALLY a wave but it's not REALLY a particle, either. It's made up of photons. People who understand physics might be able to grasp the whole thing, but I'm going to assume that since I don't understand exactly what photons are, you can understand the basics of film without really knowing what they are, too. So we're going to just go by faith that it's these photons that cause the sensitive stuff on the film to make the picture you wind up with.

This 'sensitive stuff' is made up of gelatin and something called silver-halide crystals. It's referred to as the 'emulsion' of the film. These silver-halide crystals are what detect the photons that are hitting the film and the gelatin holds it all together. When light hits them, these little crystals cluster together into bunches, depending upon how much light is hitting them, and when enough of them cluster together, you get a dark spot on your film in the shape of whatever is in your image. In color images, there are separate layers for red, green and blue that all have little crystals working together to create a final product.

ISO and Exposure

Now, in lesson two we talked about aperture and shutter speed and how they affect exposure. Since you have that down, I'll introduce a third element that we can throw in to further complicate the whole business. Your camera's film has something called a 'speed', too. It's usually referred to in units of ISO (which stands for the International Standards Organization) and typically comes in the following speeds:

ISO 25 - Slowest Film
ISO 50
ISO 100
ISO 200
ISO 400
ISO 800, 1000 and 1600 - Fastest Films

The 'faster' the film is, the more quickly it will respond to the light that hits it. Remember when we talked about Nipce needing an eight-hour exposure for his photograph to 'set' and Daguerre shortened that to a half hour? That would sort of be like Nipce using ISO 25 film and Daguerre using ISO 400 film. Of course, celluloid film is much more sensitive than that so you don't need ridiculously long exposures, but that should give you an idea of the difference in films. If you double the film speed (in ISO units), you can decrease the aperture size by one f-stop or shutter speed by one click and get an equivalent exposure.

So You would want to buy the fastest film you can get your hands on, right? Unfortunately, no. The slowest films are made up of much, much smaller silver-halide crystals. It takes those itty-bitty crystals quite a while longer to move across the film surface and cluster up where the light is directing it than faster film, which is made up of larger silver-halide crystals. The different sized crystals cause something called 'grain'. As a general rule, the faster the film, the larger the film grain. So the professionals tend to use the slowest films that they can. Grain tends to get in the way of an image and cause less 'perceived' sharpness. Grain will be especially apparent on enlargements of photographs and give the print the appearance of having freckles. Of course, grain can also be used for effect. High-contrast, black and white images can be made even more dramatic with a heavy grain, as can gritty subject matter.

This is an image where I used grain to add to the photo, artistically:

This shot was intentionally made as a very bright (referred to as 'high-key'), high-contrast image to showcase the flaming red hair and tattoo. Below is a close up viewed at 100% magnification showing the grain in the image. Without the grain, the vast white areas would just seem overexposed when viewed as a print, but the grain adds a textural feel to the image that holds it all together.

Grain is most often used creatively in black and white photography, because there are many films that lend themselves nicely to beautiful, fine grain patterns. It's best to go with a film that will eliminate any grain unless you have a reason for wanting it there.

Here's a chart of sorts to give you an idea of which films work best for what lighting conditions:

Taking Care Of Film

Film is very delicate and also very easily damaged. Film is sensitive to all kinds of things, including X- rays (watch those airports!), chemicals (including salt if you're in an ocean environment), heat (don't leave your loaded camera in a car on a hot day), abrasion from rough handling and of course, light. Film is also susceptible to fungus if kept in high humidity, which will cause blotches, so be careful of that, too. Film that has gotten old or been exposed to high temperatures may have an ugly greenish tint or a mottled appearance. X-rays will cause unsightly lines and impressions in your developed film. And rough handling will be apparent in spots that show up looking like cracks, flecks or the actual appearance of the film looking torn or broken. If you buy film and are going to use it within a couple of weeks, you can keep it at room temperature. If you stock up and plan on keeping your film around for a while, however, you should store it in your refrigerator. Be good to your film and it will be good to you!

Types Of Film

Now that you have a general idea of how film works, we can talk about all of the different types of film.

Negative Film - Also Called Print Film
If you are looking to wind up with a nice set of prints, this is mostly the type of film you will use. The film box will usually say something like 'film for color prints'. You take your roll of photographs, then your exposed film will have to be processed by a lab to create a 'negative'. You've all seen these - the colors are reversed. The negative is then used to produce a print using the 'positive' colors. A piece of equipment called an enlarger is used to project the negative image onto light sensitive printing paper. Then in the last step, that paper itself is processed to give you your print.

One good thing about negative film is that even if you expose it incorrectly, there is still usually enough detail in the negative that a print can be made to look just fine. In fact, the machines that printers use today are 'smart' enough that they know if you've exposed your print wrong and will automatically print it to the exposure it thinks is correct. A handy thing for that picture of grandma blowing out her birthday candles when the flash didn't go off, but not at all good for learning photography. You might think you're exposing your photographs correctly, but the 'smart' printing machine is actually fixing any mistakes you might be making. You can be off by two or three f-stops and never even know when you look at your final prints.

Positive Film - Also Called Slide or Transparency Film
Positive film, as you might expect, is the opposite of negative film. After processing the film you will have a set of positive images - also called slides or transparencies. If you want to make a living with photography, slide film is the only way to go - agencies, editors and print houses will only accept a print if it is phenomenal and they have no other choice. Normally they will only take slides (though more and more they are moving into the world of digital, too - but I'm sticking to just discussing film for the moment).

We talked about negatives above and how you can vary your exposure and still get a good print. Slide film is not forgiving in that manner at all - slight over- or underexposure is nowhere near as tolerable as color negative film. There are a couple of bonuses to that. Number one: You will definitely learn how to expose your film properly using slide film, and working the manual controls on your camera will become so second-nature you won't even have to think about it. Number two: Color slide film reproduces faithfully and immediately exactly what you've seen though your viewfinder. There's only one step - to develop the film. No running through an enlarger onto light-sensitive paper and then having to develop that paper - no machines trying to interpret what you might have wanted that image to look like, so there are way fewer steps in which to screw up your artistic vision.

The other great thing about transparency film is the amazing color saturation you can get. No print film in the world can match the beautiful colors you can capture on transparency film specially formulated for landscapes. They also make special transparency film for portraits and other uses. There are too many different films for me to discuss specifics here, but a trip to your camera store to discuss the various professional transparency films that they stock can be a real eye-opener. I highly recommend test-driving some of these films - once you've got proper exposure mastered, you'll be amazed at your results.

Black And White Film
Color negative and transparency film are the two most common types of film, but one of the most fun films is black and white film. Whereas color film requires a considerable expense in the materials needed to develop and print your own images, black and white does not, meaning it gives you the freedom to do so relatively inexpensively. Without actually having a hands-on class, I won't go into the details of processing black and white film, but if you ever get the chance, you should give it a try. Working in a darkroom is great fun and when you're finished and have that final print in your hands that you created yourself, it's a very rewarding experience.

Infrared Film

I'll touch on a couple more unusual types of film while we're discussing different kinds. Infrared film has some really unusual characteristics that can make beautiful effects. While our eyes can't see the infrared portion of the spectrum, this film can. Human skin and foliage both tend to reflect a LOT of infrared light, so if you use black and white infrared film to take pictures of either people or landscapes with a lot of green leaves or grass, you'll get beautiful creamy white tones that almost seem to have a ghostly glow to them. Skies will turn an inky black while puffy clouds will stand out brightly. I've seen wedding photographs shot with infrared film that turned out to be masterpieces, and if you use infrared film for portraits on someone who happens to have an abundance of blemishes on their face, you'll get back images where the subject has beautiful, glowing skin - because the blemishes don't reflect infrared light any differently than the person's unblemished skin.

A word of warning, however - shooting infrared is very different than shooting regular film. Just like our eyes can't see infrared, a camera's light meter can't see it either, so figuring out the proper exposure can be tricky. Many photographers use a system of setting the camera's aperture the way they want it and then using varying shutter speeds, making notes as they go. Then when you develop your film, you can see which shutter speed worked best and use that as a rule of thumb. This process is called 'bracketing' your exposures, and can be handy in any tricky light situation, not just when using infrared film.

You'll also need a filter for your camera that will filter out all but the infrared light - there are several to choose from, and I'd suggest a trip to your local camera shop to discuss the pros and cons of what they might have available. Another important thing to note is that infrared film must be both loaded into your camera and removed in absolute darkness or you can ruin your images.

Infrared has lots of goofy little quirks like that, but having your first successful prints done with infrared is an exciting and rewarding experience. It's like seeing a world that you normally wouldn't know existed. Most of the time the film manufacturer includes specific directions on important facts you need to know when handling the film, so pay attention to those and you should be fine.

Tungsten-Balanced Film

When we walk outdoors after being inside with artificial light, our eyes don't perceive much of a difference in the colors of things around us. Film, however, doesn't have the latitude that our eyes do and it will give your images very unusual color casts if your lighting is not exactly the specific 'temperature' that the film was created for. Most films are balanced for natural lighting - daylight.

The Kelvin scale is what is used to measure the temperature of different types of light. The 'warm', vanilla-colored light that you see at sunrise, sunset, and in indoors measures between 2000K and 3000K. The 'cool', bluish tinted lighting you see outdoors when it's overcast measures around 7500K. During the day when the light is bright, it's considered 'white' and its temperature is about 5000K.

So that means that if you use film balanced for daylight when you're indoors under tungsten light the color will be incorrectly balanced and the image will have a yellow or orange color cast. They make tungsten-balanced film to correct this problem. Likewise, if you then take your tungsten-balanced film outdoors and try and shoot a landscape, you'll find the opposite, a bluish color cast.

One of the best uses of tungsten balanced light that I've found is for photographing Christmas lights during the winter. If you use regular film for this, a lot of times your photos will come back and those spectacular colors of the Christmas lights will all come back looking white or yellow. With tungsten-balanced film, all those marvelous colors will show up as big as life and you'll get exceptional photographs.

If you're shooting indoors under artificial light, you may want to give tungsten-balanced color film a try. Negative film is normally daylight-balanced, but because the printing process automatically adjusts for color temperature differences, you generally won't notice any odd color cast when you get your prints back from the lab if you took your pictures indoors.

What About Digital Cameras?

Since I know this is an online class and that means many of you are probably doing work digitally, how does any of this apply to you? If your digital camera has manual settings, what do those ISO markings mean? You're not using film - what's the point of having them on a digital camera?

You're right, digital cameras don't use film. They have image sensors that work in place of film. That ISO marking means that the camera will set it's little computer to work as if it had that type of film in it, making that number it's ISO equivalent. Just like film having larger grain with the faster ISOs, using a faster ISO in your digital camera will give you a 'noisier' image. Noise is sort of the digital equivalent of grain. Just like film, you'll get the best image quality when you use your lowest ISO settings available. This will require longer exposures, so a tripod might be necessary.

Okay, so what about all that light and color temperature stuff?

If you have a DSLR camera or other professional camera that has the capability of taking photographs in RAW format, you can always go in and change the white balance or exposure after you've taken your photographs. When you take a photograph in RAW format, your image sensor records it just like it sees it and doesn't add ANY sort of white balance to the shot and when you upload it to your computer, you can then go in and make all sort of incremental adjustments until the shot is just right. I shoot almost exclusively in RAW format with my digital camera.

If you don't have a camera that will let you take photos in RAW format, your camera probably comes with settings you can use for daylight, cloudy, incandescent, fluorescent and other types of lighting, depending on the camera. You can also use your camera's auto white balance, but beware - if the camera guesses wrong and you need to go in and make changes using photo-editing software, image quality degrades as you make changes to your picture. It's best to always set your white balance manually if you can.