Film Development Testing Question

[Larry Gebhardt]

So getting anything beyond trays did not make sense to me, until xkaes mentioned tubes, which (yay! -- and I'm not being sarcastic) gives me something else to explore; Can anyone give me some links to more on them?

Search for "BZTS tubes homemade" and you will find a lot of results. I tried them for 4x5 and found they worked well. I used grey pvc electrical conduit for my set. I think the originals are welding rod holders.

[Paul Kinzer]

Paul,

I think you're overlooking the obvious. Why not find a scene that has an even distribution of tones, meter carefully and shoot a couple of sheets of 5x7 film.

Then, when testing developing times, simply cut each sheet in half (lengthwise is likely best) and tray develop at four different times. If that doesn't get you in the ballpark for a developing time, you're not designing your test well enough. And, you've practiced tray developing sheet film as well.

FWIW, film-speed tests are largely superfluous unless you are using a rather esoteric developer. If you plan to use the Zone System, just start by rating your film 2/3 stop slower than box speed. That will be very close; likely within a third of a stop. If not, then just use box speed to start with. Do your development tests and pick one that seems close to what you want (or extrapolate an intermediate time). Use this as a starting point for shooting real scenes. Keep notes and adjust speed and developing times as you go if needed.

Best,

Doremus

Thanks, Doremus!

What you say make sense, though it would leave out the other reason I wanted to try several different shots: testing my lenses. Still, I could just assume that the only lenses that need testing are those with flaws, and there are only two of them.

Still, a roll of 120 film costs about the same as two sheets of 5x7 ($4.59 compared to about $4.00). I know I'll be ruining this film and would miss the 120 less than the 5x7. $4.00 is not too significant a cost (even for me), but it would be two less shots out of a box of 25.

[Paul Kinzer]

Search for "BZTS tubes homemade" and you will find a lot of results. I tried them for 4x5 and found they worked well. I used grey pvc electrical conduit for my set. I think the originals are welding rod holders.

Thanks, I'm on my way!

[xkaes]

What you say make sense, though it would leave out the other reason I wanted to try several different shots: testing my lenses. Still, I could just assume that the only lenses that need testing are those with flaws, and there are only two of them.

What kinds of flaws do you suspect? Are they with the glass or the shutter?

[Willie]

Use 5x7 and don't look back. Might as well make the mistakes on the film you will be using. One shot developer makes sense. Why worry about wasting some when it is consistency and quality you are working at? Stop, fix and rinse are easy. Getting the feel and your working methods figured out is not difficult if you are doing it with the film size you will be shooting. Waste a sheet by walking it through in the light and then a few times with your eyes closed. Then do one in the dark. You will probably be pleasantly surprised at how easy it is.

If you are worried about scratches you can always do one sheet at a time with Brush development. Easy and very clean negatives.

[xkaes]

If you want to do the zone system "photograph a gray card" type test to read on a densitometer, you can easily do so with just one sheet of film.

Find a black plastic or cardboard sheet, or spare darkslides. You will need three. Make a round hole in each about 3/4 inch diameter. Placing the hole is important. Imagine dividing the area of the film into six equal sections, you need a hole for each section. Darkslide 1 will put a round exposure in section 1, and then if you flip it over it will expose section 2. Darkslide 2 will provide two dots, etc. To be clear, once the film holder is in the camera, you replace the original darkslide with the first modified one and make the exposure so only the small section is given light. Once all six exposures are made you put the normal darkslide back in and remove the film holder from the camera.

When processed, your negative has two columns of three dots each (when the negative is held vertically), each dot increasing in density.

That's EXACTLY what I have done, and it works great. I just didn't know how to phrase it -- without pictures -- so that anyone would understand. The only problem I have had is the hole in the darkslide getting caught in the felt in the holder. But brute force works!

[Paul Kinzer]

Great suggestions! I'm feeling pretty good, too, that I've learned enough from my reading and other research to actually understand most of them!

The flaws are in the glass of two lenses: some haze in one, and minor -- though not growing -- fungus in another.

[R.K]

That's EXACTLY what I have done, and it works great. I just didn't know how to phrase it -- without pictures -- so that anyone would understand. The only problem I have had is the hole in the darkslide getting caught in the felt in the holder. But brute force works!

To avoid this, before pulling dark slide with hole out, slide in some sheet of film between the dark slide and the holder and after pull dark slide together with that film out. And don't worry this is a light proof method, I did it previously. I even used a NY subway metro card instead of film. It works.

[xkaes]

Great suggestions! I'm feeling pretty good, too, that I've learned enough from my reading and other research to actually understand most of them!

The flaws are in the glass of two lenses: some haze in one, and minor -- though not growing -- fungus in another.

These would have to be pretty severe to impact the exposure, but they could impact the quality of the image. So once you determine a good exposure for a scene and film, take a picture with a good lens, as a base, and additional ones with the potential problem lenses. If you have a resolution test chart you could use that, but a picture of a spread out newspaper would be just as able to show any defects.

[Larry Gebhardt]

Great suggestions! I'm feeling pretty good, too, that I've learned enough from my reading and other research to actually understand most of them!

The flaws are in the glass of two lenses: some haze in one, and minor -- though not growing -- fungus in another.

Haze will cut contrast and should be cleaned up before you base your development and exposure testing on shots using this lens. Fungus could too, though it's usually on the edges and not in the image path at normal apertures in my limited experience.