Is this Ilford comment good for other films, too?

[kivis]

Advertisement (gone after registration)

As quoted in The Online Photographer:

 

So here's how to shoot XP2 Super, according to me. It's simple. This yields the highest percentage of results of the best quality—I don't care a whit for "make do" solutions that yield only acceptable results. Using camera metering:

 

• For regular shooting in most normal lighting, use EI (ISO) 200.

 

• For shooting in extremely bright and/or contrasty lighting, like harsh full sun and shadows, use EI (ISO) 100. This insures adequate shadow detail, and the highlights won't block up.

 

• For shooting in low and low-contrast lighting—and this includes indoor shooting and "available darkness"—use EI (ISO) 400—or even a little higher, although I personally don't recommend ever going all the way to (gasp) 800.

 

That's it. Beyond those adjustments made to accomodate the prevailing light, you can let the camera's meter set the exposure and you'll get a high percentage of good results (a bit higher, of course, if your metering skills are good). And you can switch settings on the same roll all you want—the processing is not adjusted and is always the same.

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[adan]

It is generally good advice for CHROMOGENIC NEGATIVE films of all types - i.e., those where the final image is formed from dyes and not silver. Put simply - any film that uses the C-41 process, whether monochrome (XP2, BW400CN), or normal-color negatives.

 

The reason being that the dye-cloud "grains" of such films get very clotted and ugly in the shadows if the films are underexposed. Unlike silver grains, which are generally hard-edged and "sharp", the dye clouds have blurred, soft edges.

 

And if underexposure means the clouds are not big enough to overlap, the exposed soft "grain" edges in the shadows simply look as though your enlarger (or scanner) was out of focus. Mushy.

 

In short, chromogenic neg films have a higher tolerance for overexposure than for underexposure.

 

Additionally, unless you have a good custom lab that can adjust their processing line to change C-41 development times (push/pull) per roll - C-41 is a "one-size-fits-all" process. Unlike traditional B&W where you can "expose for the shadows and develop for the highlights".

 

So the only way to adjust for scene contrast is through camera exposure.

 

The comment DOES NOT apply to color slide films, or to traditional silver-image B&W films. Shoot ISO 400 slide film at two stops over (EI 100) in "extremely bright and/or contrasty lighting, like harsh full sun and shadows" - and you will blow the highlights irretrievably (detailless transparent film). Overexpose silver B&W neg films, and the highlights can get grainer and blocked (poor separation between whites and almost-whites).

 

basic rules of thumb:

 

chromogenic neg films - expose for the shadows, let the highlights fall where they will

chromogenic slide films - expose for the highlights, let the shadows fall where they will

silver B&W films - expose for the shadows, develop for the highlights

[CalArts 99]

 

chromogenic neg films - expose for the shadows, let the highlights fall where they will

chromogenic slide films - expose for the highlights, let the shadows fall where they will

silver B&W films - expose for the shadows, develop for the highlights

 

Good post. This is something all film users should be familiar with. I'm happy that there are a lot of new users of film appearing all the time these days, but it's unfortunate that there's no real source for them to learn about film use. It's mostly trial and error or asking each other questions, etc.. We still teach film use in the university system here but there are many institutions that have stopped altogether.

[Jeff S]

Of course there are exceptions to every rule. Fred Picker, for instance, advocated (using Tri-X) to expose for the highlights, placing the highest tone where one wants detail on Zone VIII. This was one concept in his broader process to measure film speed and development times, etc. He made some beautiful prints.

 

Whatever works for YOUR subject matter, style, materials and workflow is the key, as long as you understand why and how it works, and can replicate or change the process as needed.

 

Jeff

[CalArts 99]

That would work okay too, with a film like Tri-X with a pronounced toe. And when the scene is around 4-5 stops difference. The shadow then gets into Zone III or so and all is well.

 

Much of how one works is dependent on a lot of factors including the materials. But certain adages like "exposure controls density and development controls contrast" are probably just good things to have in the back of one's mind.

[RED ROBIN]

For newbies to film be on the lookout for old how-to camera books. Most of my color books have been read and passed on but I've held on to the B&W. Hard to beet a good reference collection.

[Jeff S]

Advertisement (gone after registration)

That would work okay too, with a film like Tri-X with a pronounced toe. And when the scene is around 4-5 stops difference. The shadow then gets into Zone III or so and all is well. Much of how one works is dependent on a lot of factors including the materials.

 

Exactly so, which is why Picker used this method, given his typical subject matter and materials. And why I noted that others should consider their own circumstances when determining an appropriate workflow.

 

But certain adages like "exposure controls density and development controls contrast" are probably just good things to have in the back of one's mind.

 

And this is why Picker, for example, sometimes made a second exposure for some lower contrast scenes, placing the desired bright area on Zone VI 1/2 and then developing longer (using sheet film) to add contrast. Of course papers and other variables come into play.

 

At the end of the day, the technical aspects…the 'how to' part... can be learned easily and well. There are lots of ways to get the basics. But the much harder part is having the 'eye' to know when and where to make adjustments to create a print that works. It's like the old joke about the surgeon responding to criticism about charging so much money for a simple incision, saying that the cut is easy, but knowing when and where to cut is the tough part.

 

Jeff

[adan]

If I may expand a bit -

 

@ Jeff S and CalArts 99: exactly. I just shot my first Tri-X in years, using a incident meter, and boy did the highlights block up with an "average" exposure in sunlight, or opening up for backlight. Glad to hear about the Picker approach (and the reminder of why it works - for Tri-X). Will try my next roll with more of a highlight bias. Tri-X of course also has extended blue sensitivity, so skies especially are not treated well by an average exposure for middle-grays.

 

As to chromogenic vs. silver films. just a further explanation of the image structure differences, for those unfamiliar with them.

 

In traditional silver films, the final image is the silver itself. Literally, silver metal precipitated out of a silver halide compound through exposure and the chemical reaction with developer. And as one would expect from a pure metal, it is totally opaque. However, the silver atoms hang together as crystal-like structures, and many of these together form the lumps that we see as "grain." Still fully opaque and hard-edged wherever there is metal, but with gaps of random sizes that allow light to pass in varying amounts, producing grays.

 

Film Grain is Binary (*or is it?) - digital Artform

 

"Fine-grain" developers such as Microdol-X contain an extra-high dose of sodium sulfite, which dissolves some of the silver (converts it to silver sulfide) even as it is being developed, shrinking the visible grain at the cost of some film speed (less silver in the final image for a given exposure, so a lower EI should be used to prevent a "thin" negative). But the grain does not get more transparent, the opaque areas just get smaller.

 

In chromogenic films, as the silver develops, the development by-products diffusing out from each silver particle react with dye-coupler compounds in the film (even monochrome films) to form a dye "cloud" centered around the silver bit. The clouds are translucent, and diffuse outwards from the core silver particle, getting more and more transparent towards the edges. The silver is eliminated altogether from the image by the bleach/fix, leaving just the dye clouds as the final visible image.

 

In color films, the dye clouds are colored cyan, magenta and yellow, but since they are translucent, they act as little filters, and can overlap to form red, green, blue or all the other colors. (In monochome dye films like XP2, the dye is gray, but still translucent).

 

http://static.photo.net/attachments/bboard/00a/00aeYj-484975684.jpg

 

If the film is underexposed, the dye clouds fail to overlap, leading to mushy speckles rather than smaller, but still hard-edged, silver grains.

_________________

 

Incidentally - the difference in image structure is why scanner dust-removal software works with chromogenic films, but not with silver films. The image dyes** are transparent to infrared, and thus a scan in infrared light will make all of the image invisible - except for opaque artifacts like dust or scratches. The IR scan can then be used to "patch" the full-spectrum scan.

 

Metallic silver is opaque to infrared, just as it is to visible light. So the IR trick won't work - the scanner sees the whole image as a mass of dust to be removed or patched, leading to a scan that looks moth-eaten.

 

**Kodachrome dyes are more opaque to IR than E-3/4/5/6 or C-22/41 dyes, thus they can also fool the dust-removal software and can lead to scanning artifacts.

[StS]

(...)I just shot my first Tri-X in years, using a incident meter, and boy did the highlights block up with an "average" exposure in sunlight, (...)

 

Part of this effect can be the spectral response of the film to sunlight, which has a high UV content. Looking in the data sheet for Tri-X, there is a spectral sensitivity curve on page 10. It shows, that the film has it's maximum sensitivity @ 400 nm, which is violet, at the border to UV, staying very sensitive when going to shorter wavelenthgs in the UV.

 

When I'm using Tri-X, I add a yellow filter (sometimes also yellow-green).

 

As a side note, looking at the spectral sensitivity curve of BW400, page 5, the film appears to come with a built-in yellow filter, with the sensitivity decreasing steeply from 430 nm to the shorter wavelenghts.

 

Stefan