Making an Improvised Infrared Transmitting Filter
I just determined what I had long suspected. I measured the spectral transmission characteristics of one and two thicknesses of unexposed but developed E6 films and found them to be comparable to that of a Wratten 87 IR filter. In addition I also made some pix on HIE film through two sheets of D max EF sheet film and compared the pix to some taken through a "standard" IR filter, the Wratten 87.
The result of this is that it appears that one thickness of E6 film is roughly the equivalent of an 87 filter but with a broader spectral response and with some 1% transmission valleys at 500 and 600 nm. Its transmission starts to drop from 1% at 700 nm to about 95% at 800 nm. Two thicknesses of D max E6 are basically visually opaque with transmission dropping rapidly starting at 720 nm and dropping quite rapidly to 90% or so at 850 nm.
Maybe they might be closer to what a 88 is. Basically the 2 sheets of E6 simply do not have as steep of a cutoff as the Wratten filters do nor as good a maximum transmittance. But they are serviceable!!! especially for placing over a flashgun where expensive Wratten filters tend to fry and buckle!
Picture-taking wise, the two thicknesses of E6 film did not seem to degrade image sharpness significantly when used with 4x5 format. I have not tested 35mm. They would obviously not matter much when used over a flash for inconspicuous flash photography at parties, etc.! (camera lens with or without additional filter over it).
The spectral transmission curves for the 1 and 2 sheets of E6 film, and that of a Wratten 25 and 87 filter are attached below.
Experimental Grade IR Filter spectrophotometric curves:
In case you did not know and might benefit from this information I had some filters often used for Infrared photography, along with some unexposed but developed Ektachrome sheet film, characterized with a spectrophotometer. The films were obviously visually quite opaque. Especially if you stacked two of these. It turns out that the dyes that make up the color layers in this film (and I suspect all color films) are visually opaque but IR TRANSPARENT! This means they can be used as cheap makeshift IR filters, especially to cover a flash source to make unobtrusive flash photos by IR illumination. This info is not totally new as I had already seen such curves at RMIT in Melbourne, Australia, where I spent my summer vacation a couple of years ago. I also used one and two layers of Ektachrome film as a filter in front of my camera's lens and the images were not totally fuzzy and unusable. They had, in fact, a visual quality all their own which you may (or may not) like if and when you experiment in a similar fashion.
Photography as we know it was originated in 1826. The first known picture was taken by the French inventor named Nicephore Niepce. The image taken by the Niepce's camera required to be exposed to bright sunlight during eight hours to be recorded properly. Since then the process of taking photos has greatly improved through the history of photography development. Nowadays it takes only a few hours or less to process photos taken with a camera using photographic film (usually 35mm). With digital cameras it is even easier - in most cases you can see a picture on the LCD display immediately after it has been taken and then load it into your computer; the photo is then easily viewed, printed, e-mailed, edited, etc. It is also possible to take instant pictures that take seconds to develop, like the ones taken by a Polaroid camera.
The word "photography" comes from Greek words "phos" (light) and "graphos" ("stylus", or an instrument for writing or drawing). So literally, "photography" is a process of creating an image or a pattern by means of light. This definition is absolutely correct: a so-called latent (negative) image is created with an analog camera by exposing a recording medium, such as photographic film, to light; it is then being developed and printed to become a realistic (positive) picture. With digital cameras a realistic image is created on a recording medium, such as digital storage card, immediately after a shot has been taken.
After being invented, photography soon widely entered the life of middle-class people as an alternative to oil painted portraits that were much more expensive; photographs either weren't cheap at that time, though. Ever since then photography had wide commercial use. In the late 19th century more than 80% of all pictures were taken by commercial photographers. However, with development of the technology and cameras becoming more available, more and more people started to privately use photography.
Nowadays photography is being used for numerous different purposes. It serves to preserve memories and as a kind of entertainment for families or groups of people like friends, schoolmates or coworkers. Police, military and secret services use it for surveillance, recognition and data storage. Photographs are also essential for mass media and literature as illustrations for publications and news coverage. Photojournalism is extremely important since the picture in a press-release is sometimes more informative than the text itself. Photography is also a sophisticated and profound form of art that has numerous maestros and connoisseurs.
Currently various kinds and types of cameras are available on the market. They are used for different purposes and have their own advantages and disadvantages; their prices can vary dramatically from model to model, too. It can be a very hard task to pick the camera that is right exactly for your individual case. But don't get worried - the information on this website should help you make the correct choice. Learn what features to look for in a camera depending on what you are going to use it for.
One of the major arguments going on in the world of photography is the one about which format is superior: digital or film. Actually, there is no particular answer to this question; each one of these two formats has its own advantages and weak points. Numerous facts and test results showing those of both of them are available on this website. Check them out to decide which format is perfect for you.
Technology is developing extremely fast nowadays. Sometimes a model can become out-of-date one even before its official release! Some features are folded; some are only being introduced into mass production. Who would have thought that a digital camera, so rare a decade ago, would become so popular and widely available in such a short period of time. Keep yourself familiar with the latest information on photo industry with our website; don't miss any innovations and recent developments - don't fall behind!
Although photography seems to be a relatively easy process, it takes years of learning and practice to achieve a sufficient level of skill in it. Professional photographers can learn during their whole life and still may not know all the little secrets and details of the process. Nevertheless, after spending some time on studying the photography basics, everybody can learn to make decent pictures with a relatively inexpensive camera.
So doesn't matter whether you're just an amateur shooter or a professional photographer, whether you're just starting out or looking to improve your skills - you're sure going to find lots of useful information on this website. Recent reviews of modern high-tech cameras, sophisticated shooting techniques, descriptions of the newest software products, most common and extremely rare pieces of equipment and accessories, tips and hints on taking, processing, editing and printing pictures, and plenty of other information that any photographer should be familiar with to be able to make his pictures true pieces of art.