26 May 2014

Photography Monday: Chromogenic Black and White film a technical lesson and review.

Welcome back to Photography Monday. Today we are going to talk about chromogenic black and white films or simply put black and white films that can be developed in color chemicals. Today a technical lesson and a review is presented.

Technical Lesson:

Okay so we know what chromogenic black and white film is, now lets get into details on how it works. As you may know all traditional film works with a silver halide emulsion that is sensitive to light. Most color films work by coupling this to multiple color dyes. When color film is processed the silver halide is developed and the color dyes are activated in the exposed areas. The developed silver is then bleached back into silver halide and fixed away, the color dies are then stabilized and the color image remains. This is known as chromogenic film. Now chromogenic black and white film works the same way, but instead of multiple color sensitive layers and color dyes a single panochromatic layer and a black dye are used.

What films are available and what are the differences:

This is where things get tricky. There are only two films out there and they vary quite a bit. Both films are 400 ISO. Also with both films you should tell your photo finisher that you want the prints in black and white, otherwise you may have color tints.

First you have Kodak with BW400CN. Kodak's offering is designed to directly drop in into all color processes both those using optical printing and for modern systems using scanning and digital printing. This means the film still has the orange base used by most color negative films and that printing optically with black and white paper is an issue though. Kodak's offering is available in 36 exposure 35mm rolls. You may still find some old stock or the recently discontinued 24 exposure rolls. This film is not available in medium format.

The second offering is Ilford's XP2 Super. This film has a clear base and can be printed by both the scanning method used most modern labs and optically printing to black and white paper. There will be color tinting when printing optically to color paper. Ilford's offering is available in 35mm with 24 and 36 exposure rolls, a 100 foot bulk roll, in addition to a 27 exposure single use camera. Ilford's offering is also available in 120 rolls as well.

The Review:

I recently shot a roll of BW400CN I picked up at LA Cameras in Chambersburg, Pa. The film is a nice 400 ISO film similar to T-Max (in fact the emulsion is the same purple color) with the tabular grain. Contrast is great if not a bit high. Latitude is similar to that of color print film. The tones in the images are represented very accurately. I let the LA Cameras know that the images were in black and white and the equipment was set up accordingly. Every image came out great except for the one trick shot I did and that was photographer error and the film performed properly. I would recommend this film. This example was taken with this film and a Canon EOS Rebel G:


12 May 2014

Photography Monday: Tips for 35mm Film users

Hello and welcome to our new feature, Photography Monday. On Photography Monday a photo topic is presented. This week's photo Monday is about using and managing film.

Why Film?

In this digital age you may be asking why I am talking about film, let alone shooting it. First, film cameras are inexpensive today on the used market. I bought a Canon EOS Rebel G the other month for about $25 and since have mostly put my money into accessories and lenses. An entry level DSLR (digital) New would have been about $500 not including accessories such as a high speed memory card and extra batteries.

Second, film is now in use by people looking for an alternative look to their photos, either a look that digital cannot provide faithfully such as true black and white or even the Lomography craze of low fidelity analog photography.

Lastly, beginners should at least shoot one roll of film successfully so they understand the importance of planning and photographic knowledge. This to me is the most important. Anyone can randomly take digital pictures and randomly tweak settings and get lucky. Also sometimes the ability to delete bad photos or the ability to just store them makes us less careful in making our photos.

Okay, now that's out of the way this is real meat and potatoes

While most of the tips I offer today are what I use for 35mm these procedures can be adapted to medium format as well especially for you lomographers out there.

First: if you plan on shooting your film prior to the expiration date, don't worry too much about storage temperature as long as the temperature is comfortable for you to live in. I probably have the pros cringing at this point, but the reality is film will not go bad just because it 80 degrees Fahrenheit as long as you use it prior to the expiration date. Cold storage is only needed if you want to extend the life of your film beyond the expiration date. Obviously for those looking for the lomo effects of expired film or mistreated film need to know this as well because there is more tolerance than the package says.

Second: Keep at least some of your film in your bag. If you are still concerned about temperature for some of your films, keep some less sensitive films (black and white as well as consumer films fit this bill) in your bag. Cold stored film is useless if it is in the freezer and you run out and don't have time to let it warm up before you loose your opportunity. When storing the film use either the canister the cassette comes in for 35mm or the box for medium format. This goes to our third tip.

Third: Label your film. Now if you are keeping it in the box, you already have this step covered. If you are storing in the canisters use a label maker to label your film canisters. This is the format I use:

"[Film Manufactuer] [Film name] [ISO speed] ISO [Exposure count] Exposures"
"[Description of color] [Process Type]"

Here are a few examples note that if the name ends with the ISO it is skipped as the ISO is the next piece of data anyway:

Fuji 200 (Supera):
"Fuji Supera 200 ISO 24 Exposures"
"Natural Color Process C-41"

Kodak Ektar 100:
"Kodak Ektar 100 ISO 36 Exposures"
"Vivid Color Process C-41"

Now up to this point everything has been a color C-41 film. What about black and white?

Kodak BW400CN 24 exposure:
"Kodak BW400CN 400 ISO 24 Exposures"
"Black and White Process C-41"

And non C-41:

Ilford Delta 400 36 Exposures:
"Ilford Delta 400 ISO 36 Exposures"
"Black and White Process in B&W chemicals"

Fuji Velvia 50:
"Fuji Velvia 50 ISO 36 Exposures"
"Vivid Color Process E-6"

Of course let's include Provia (note the exception to the rule above about the ISO as there is a letter after the ISO):
"Fuji Provia 100F 100 ISO 36 Exposures"
"Natural Color Process E-6"

What about other non standard films and processes, in this case we need to adapt our labeling system.

Ilford Delta 3200:
"Ilford Delta 3200 EI 3200 36 exposures"
"Black and White Process in black and white chemicals per instructions"

In the above example we have a film that is sold by a recommended exposure index and not the ISO speed. Since EI comes before the actual EI data the 3200 needs printed twice once in the film name and once again after the EI designator. A "per instructions" note is added to the process information as this film is processed differently as it is push processed to get the box speed.

Now things get tricky, what if we have a film that not only has a recommend EI, special processing, and NO DX code. We now need to indicate a lot. Since I also put an unexposed label across the top of all my canisters that label simply can be changed to read "NO DX" but what about the main label.

Bluefire Police:
"Bluefire Police EI 80 36 Exposures with NO DX"
"Black and White PROCESS PER INSTRUCTIONS ONLY"

This is a case where not only do we have an EI suggestion of 80 since there is no ISO standard for this type, it also requires special processing per the instructions, Normal developers will not get proper results. Since the process is so important and special the process information is in all capitals. Also NO DX is listed again as this is important and the speed has to be set manually.

Fourth: Process promptly doesn't mean immediately. Film always says "process promptly." This is for the best contrast and best image quality. This also doesn't mean you can't wait a bit to have the film processed. For snapshot use waiting up til a year can be safe, for more important photos a few months is still okay.

Fifth: Don't fear the X-Ray machine. Unless you are carrying very sensitive film or film that you will push process to a higher exposure index (higher than 800) or specialty process (DR-5) you have more to worry about digital than film with X-Rays. Even after an excessive number of X-Ray screenings it was found that ISO 800 film suffered no ill effect. Obviously you should only keep film in your carry on luggage as the scanners for checked luggage are stronger, vary in intensity, and have not been tested. There have been stories of people traveling with both film and digital and found that their memory cards were corrupted due to the multiple X-Rays from the cruise liner and the film was unaffected.

06 May 2014

Of VTVMs and FET VMs

Anybody that has gotten into electronics in the past 10 to 15 years is familiar with the digital multimeter and the Volt Ohm Meter. The differences are obvious, the VOM can load down the circuit but allows you to see changes in the circuit on an analog scale. The DMM is rather sensitive and won't load down the circuit, but updates slowly and only provides a digital readout or at best a bar graph display. Can't we have the best of both worlds?

Prior to the digital multmeter and even transistorized electronics we had what was called a vacuum tube volt meter (VTVM). These high sensitivity instruments allowed us to take measurements on electronic circuits without loading them down like a VOM would and of course digital was a few decades away. The VTVM was the best voltage measuring device out there for electronics work. The big disadvantage of the VTVM was that even portable units required a power line connection and multiple vacuum tubes even though later hybrid units only required one (solid state rectifier and solid state diodes for the AC scale).  While I own a VTVM of the hybrid variety, I need to build a probe adapter to replace the missing switching probe that should have come with the unit. As technology progressed with the field effect transistor a VTVM no longer actually required tubes. VTVMs stuck around a while in the FET era until the DMM took over

This is where the FET VM or FET Multimeter comes in. The FET Multimeter is a solid state VTVM and can be made in a battery portable package such as the Sencore FE23 Little Henry Field Effect Multimeter. In fact I just acquired one of these at the local hamfest this past weekend. The FET multimeter gives you the portability of a VOM with the versatility of a VTVM. In addition this unit has a light bulb in it to illuminate the scale. These extremely versatile instruments were made in the 1960s and 1970s, but unfortunately like VTVMs fell victim to the new digital multimeter technology.

While these older instruments are no longer being manufactured they can be found on the used market and are a useful tool to have around the lab or shop.