As the day progresses, the light temperature changes. Light temperature is measured in "Kelvin" This chart shows the approximate color temperature for different types of daylight and bulbs. Remember: precise color temperature can vary from moment to moment and even from expert to expert. Plus, light bulbs change colors (become "warmer") as they age...

These two photographs reveal the difference between two different Kelvin temperatures. The image on the left was taken using daylight balanced film. The room is lit with a 60 watt household bulb at dusk. The white walls have gone orange and the outside light is a deep blue...

Below is a listing for all the filters that are commonly used in color photography. This chart should be used as a reference point, but remember that because the Kelvin color temperature for any light source varies greatly, you might have to adjust your print in the darkroom, too. We should note that there is some logic to the filter naming convention. Filter ABCs go into it a little bit...

All commercial infrared films are sensitive to a combination of visible and infrared light. When treated like normal film (normal speeds, no IR filter) they behave like a normal film; they show no special characteristics. "Infrared pictures without filters always produce results similar to black and white pictures, missing [the IR] tonal value graduation. Color IR pictures show a strong blue-green tint and little color differentiation...

Calculating exposures for your pinhole camera can be difficult. The Lensless Camera Mfg. Co., whose models we sell, has provided us with the following table of apertures and f-stops for their products...

A one step change in any exposure value can be achieved by changing the f-stop, shutter speed or film (to a different roll) by one step. To maintain the same exposure value, any change in one row requires the opposite change in one of the other rows.     ←Less Light More Light→ f-number (f-stop) 2.8 4 5...

Panchromatic Film - How it works Panchromatic film records all colors of light in the same tones of grey. Light Intensity (the number of photons per square inch) is what determines what shade of grey gets produced on film. How we see things Our vision is not like panchromatic film. We are most sensitive to yellow light, which is right in the middle of the visible spectrum...

A beloved friend and fellow graduate student at the University of New Mexico introduced me to the Holga in 1992. At that time, this humble camera had no "bulb" setting to accommodate long exposures, and I began to use it without flash despite this limitation. Available window light was sufficient to expose the Kodak Tri-X I faithfully used, and I made self-portraits and still lifes that the Holga transformed into provocatively psychological vignettes. After graduate school, I purchased and modified a second Holga to serve as a dedicated "bulb" camera in order to photograph more nuanced, low-level lighting situations...

In our high tech world toy and pinhole cameras remind us that a camera is just a light-tight box with a hole (aperture) at one end to admit light that strikes some light-sensitive material opposite from the hole. Cameras define and shape an image, which make them a basic component of the photographic language. To limit the choice of cameras is to reduce what one can photographically express. Building these rudimentary devices can acquaint beginners with how a camera functions and remind seasoned workers to concentrate on the subject of their imagemaking rather than the technology...

At least in theory, making a photographic panorama is entirely straightforward: take a picture, pan the camera and make a second picture partially overlapping the first, and so on as far around in any direction you please. With digital images you can assemble the separate frames with a few keystrokes using the "stitching" command in programs like Photoshop or iPhoto. The downside, however, is that precisely because these programs are almost completely automated, they also reduce the artist's role in the process - and hence the range of possible artistic outcomes. My own approach with the Holga has been to first create a new, blank Photoshop file having a large "canvas...

Given that Ansel Adams was my first and only formal photography teacher, it's probably no surprise that most of my early photographs were large-format sharply-focused B&W pictures of trees, rocks and water. Fact is, it took me years to realize that I don't even lead a fine-grained life - that while Ansel's world was timeless, monumental and sharply defined, my own world is quirky, ephemeral and decidedly fuzzy around the edges. My ability to reveal that world photographically took a great leap forward sometime around 1990 when I discovered a little plastic camera called the Holga. The Holga had one shutter speed, a fixed aperture, and a single-element plastic lens that filtered out excessive sharpness so that realism wouldn't get mistaken for reality...

I find it hard to believe that a forty dollar camera with a single plastic non-coated lens, actually a plastic magnifying glass, has had such an impact on my students and me as a photographer. I am the product of a very rigid technical school, Brooks Institute of Photography; they beat all creativity out of me. Get it right, get it sharp, get it in the camera the first time, that is how I produced most of my professional images, that is until the little camera that could. The Holga has little opportunity to excel in industrial/commercial photography, however the camera has the potential to completely change how a photographer sees and works within the fine art area of photography...

Kelvin color temperature applies to every kind of light - daylight to candlelight and beyond. Below is a listing for the on-camera filters that are commonly used in color photography. This chart should be used as a reference point because the Kelvin color temperature for any light source can vary over time. For another perspective, On-Camera Filters Colors and Effects sorts these filters by color...