Multiple Test Zones on one Sheet

[kq6up]

Sadly art is more difficult to explain

So true! However, I do have a decent eye for a tech head nerd.

[Bill Burk]

I've written a bit on how to test film.

Here's a PDF free to download:

http://beefalobill.com/imgs/20150812...dAttention.pdf

I noticed some URL's are broken since I wrote that so here's some updated links:

Resource page at Photrio
https://www.photrio.com/forum/resour...-attention.77/

Updated URL's
Recommended: Working idea - Zone System exposure - Time/CI darkroom
( https://www.photrio.com/forum/thread...arkroom.84567/ )

Recommended: Enlarger -----> Sensitometer
( https://www.photrio.com/forum/thread...tometer.92518/ )

Recommended: Great Sensitometer Shootout
( https://www.photrio.com/forum/thread...hootout.95837/ )

[Jim Noel]

In grad school I used three spare darkslides and made a hole in each one (located differently) so I could make 6 patches on one sheet. It worked well, and with 1/2 inch holes you could possible get 12 patches in three columns of four holes per column. It like take 8 darkslides to do it though.

I did similar and still have the dark slides. It only takes 3 old dark slides to make 6 exposures on a single sheet. each exposure is made to register Zone I at exposures varying by 1/3 stop. one is made at box speed,and the others are at 1/3 stop lower EI's. THe system has worked for me for about 60 years. I redo it with each new batch of film.

[Pere Casals]

I did similar and still have the dark slides. It only takes 3 old dark slides to make 6 exposures on a single sheet.

Jim, let me add another way. We may also do it with a single regular holder, we may fire the shutter many times, and each time we insert (say) 10mm more the dark slide, so we may make 12 exposures in a single sheet, the last one has the 12 exposures accumulated, the first one has a single exposure, we may provide an exponential exposure series...

I do that to find right exposures for paper negatives in pinhole, but it also may be used to test film.

[Doremus Scudder]

I guess I'll jump in here with my method, which entails using a filmholder with a darkslide marked in fifths (i.e., so one can make five exposures on one sheet of film by inserting the darkslide one-fifth of the way into the filmholder for subsequent exposures). I simply marked a darkslide with a Sharpie with lines; no drilling holes and ruining a darkslide required.

If necessary, I first determine a personal E.I. with a film speed test on one or two sheets of film. I don't do this much anymore, since experience has shown that if I just rate the film 2/3-stop slower than box speed and then keep notes any subsequent adjustments will be really small (1/3 stop usually).

For determining development times for N, and all N- and N+ times, I make Zone Rulers, using two or three sheets of film. My method is described in the attached document (from my field guide).

What's missing in the instructions is a discussion about finding the right subject for the tests. I like an evenly-lit textured wall (think stucco or smooth plaster). Using a real-life subject along with the camera and lens you use the most takes flare into account automatically and results in more usable (if less scientific) results.

Keep in mind, that the whole testing procedure is just to get us in the ballpark. Things like flare from uncoated or single-coated lenses in both camera and enlarger can make a significant difference in the low values, not to mention flare from light sources or bright areas in or just out of the image area.

Really, only consistent note-taking and making small adjustments can hone an exposure/development system. Using step tablets gives nice clear data, but they are often not relevant to what happens in actual taking situations.

Best,

Doremus

[Andrew O'Neill]

I made a Zone Board, as outlined in Gordon Hutchings', The Book of Pyro. It has worked well for me for over twenty years...

[Hans Berkhout]

Re the target for testing: an evenly lit board, wall etc can be created by using an Expo Disc on the camera lens. I use a 67mm disc which I pressed into an 67mm filter ring (discarded filter, glass removed). A second (smaller) Expo disc I hold in front of the exposure meter when taking the reading-which will be Zone V. I can make the required exposures even when it is 30 below outside: just stay indoors and aim camera at window. Make sure lens opening is such that vignetting cannot take place (look through ground glass cut off corner etc).

As an aside; the smaller Expo Disc I attached with black tape to a step-up ring fitting my enlarger lens, the prism side of the disc facing the negative. This set-up facilitates flashing of the printing paper, negative stays in place during the procedure while lens opening and/or timer are manipulated as needed.