"Essentially placing a dark cloth on zone 1, making 5 exposures
and developing by manufacturer's recommendations...
Then using a 0.1 ND filter on a piece of developed unexposed
film,comparing the 5 pieces to determine film speed."
A black bed sheet you say? As target? Then after metering
a Zone 1 exposure was made at four stops under the indicated
exposure? Then four more exposures were made adding a stop
more each ending with Zone 5?
First of all I've doubts a valid test can be made using a flat
nearly dead black target. Off hand I'd think good lighting and
a sensitive meter be required to get a reading of any sort.
Some specific gray card though is not needed. A Sturdy
Board, 20x30 inch, does me well using clear blue sky.
Remember the meter reads Zone 5. For Zone 1 under expose,
for Zone 8 over expose. A short cut is Zone 1, 2, 5, 7, and 8.
The View Camera Store has had 4x5, 21 step step tablets on
on sale off eBay; 0.05, 0.20, 0.35, and on up.
"I can't get a piece of film with equal density across it, ..."
Fields of gray. Maybe not so unusual. Dan
Michel- I think it must lose something in my condensed translation- it's Bruce Barlow's method from Circle of the Sun (which is a variation of Steve Simmons' method- the original one I tried with 35mm).
Originally Posted by mhv
Dan- For film speed, I spot metered the cloth and placed on zone 1 for ISO 64, 80, 100,125 and 250 and developed all for the same amount of time (Kodak sais 8 min in dilution B of HC-110)
Thanks Bob- I'm going to use my estimate of ISO 80 for 6 1/2 min and fine-tune it using this method.
Originally Posted by Bob F.
If you are using in-date FP4+ and are exposing and developing properly then getting the box speed of 125 should not be a problem. A few developers like Microdol-X and Perceptol, when used full strength, will cause a speed loss of about one stop. I would say that FP4+ probably gives nice results in more different developers than any general purpose b&w film. The people at Ilford have tested FP4+ a lot more than you are likely and if they say its speed is 125 IO believe them. There may be times when pushing or pulling is employed to obtain special effects or change the contrast of the final image but in most shooting situations and with most developers 125 is the right speed. Partick Gainer is right. Make sure your equipment is working properly first.
Already mentioned you need to check the shutter on your view camera. But even so I use 35mm, MF and 4X5 with 4 different lens and shutters. Even my 35mm and MF cameras vary by 1 to 3 stops. You need to test each camera for your personal film speed for each camera. BTZS, ZS, or any other approach can work as long as you use the same procedure and keep track of your findings.
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At some point - you trust a camera and a light meter - they may not be correct - but they are your system so you calibrate to your system. I have a Hassy that is likely close on shutter speeds. I have a light meter that is also probably close. My other cameras and light meters will need to also be close - they are likely within one stop and all I shoot is B&W so close is likely ok for the most part.
I find a wall and meter it. That is zone 5. I set up my hassy and calculate frames - If zone 5 is F16 at 100th - F32 at 100th is zone 3 - F45 at 250th is zone 1 - F2.8 at 100th is zone 10 - F8 at 100th is zone 7. I put the wall out of focus and shoot a frame at each zone. I shoot several rolls of several kinds of film. Then I develop and look at the zones - I want to see a difference between zone 1 and base fog. (.1 density over base plus fog) This will tell me the actual film speed in that developer. Zone 3 needs some detail in it. Zone 8 should not be past 1.5 density. - The developer/time that gets me these results is a winner - I am now calibrated. These values will be close for all formats. I keep a running log and make small adjustments as I shoot sheets or rolls.
If my zone 1 is good and zone 10 is at 1.7 density (too high) - I know to reduce the development time by 30% or so. If my first detectable zone is zone 2 or 3, I reduce my film speed - shoot at a smaller ASA - one stop or more. Exposre has the big impact on zone 1 and development time determines zone 10.
Of course all this needs to be calibrated for your media - grade 2 enlarging paper usually needs a spread of 1.25 density from white to black, grade 3 paper is about 1.0 density and azo is more like 1.5 to 1.7 density. Alternative processes are sometimes over 2.0.
You also need to consider your source contrast. Many landscapes have 7 to 10 stops in them (spot meter) and should be developed -major adjustment- (and exposed - minor adjustment-) to reveal all the important stops. For landscapes I use TRI-X at 200 and develop it in pcat-p 1:1:100 for 9 minutes and get 10 stops from DR .1 to DR 1.35 which print perfectly on grade 2 paper. For indoor shots where there are only 3 to 5 stops of contrast I can shoot TRI-X at 1600 and develop it in XTOL 1:3 for 20 minutes and will get 5 stops from .4 to 1.5 which will work well on grade 2 or 3. For low contrast landscapes (the bulk of my work) I use FP4+ LF and shoot it at ASA 80 - develop it in pcat-p 1:1:150 for 54 minutes with aggitations every 11 minutes - I get 5 zones spread from .25 to 1.5 with extra sharpness and some highlight compensation. This is my main choice for the bulk of my work - even portraits!
You can experiment to find what works best or you can get scientific. I got my Densitometer on e-bay for $100 and it opened the world up to me. Compare the $1/quality improvement of this to my last LF lens $1300 for a Schneider 47mm XL and it is a bargain! You can get a step wedge and eyeball your negs and get a pretty good idea where the densities are. You can print your step wedge and see your paper lattitude and get the same thing done for less than $50 as well.
I am more interested in images and art than in science and testing - but the knowledge gained from a LITTLE testing makes a huge difference in my results.
My photos are always without all that distracting color ...
Originally Posted by timbo10ca
I have found that the empirical method of film testing (without a densitometer) works best when focusing on a textured target rather than using infinity. I used a veneered piece of plywood with window screen attached very flatly and then both spray painted over to closely match the tone of the gray card. The inspection method can work, and I have found that I have better judgement when I give my eye something to focus on rather than just looking at a print tone alone from a blurred negative image. With the empirical method your inspection is easier when juding a textured surface, at least it was for me.
Thanks Chuck- I'll try something like that if I go through this again. I'm tired of it, but I'm also stubborn as a mule. It bothers me that I'm having trouble with something that seems so inherently simple. :rolleyes:
Originally Posted by Chuck1
I have and use densitometers but a habit I've found handy that is simple and intuitive is to use a Kodak gray card with a Stouffer RZ9 strip glued to the edge as a target. On roll films, I shoot a frame with this target and interpret the tone separations. It is very easy to decide if I've under/overdeveloped and/or under/overexposed from a quick glance at the negative. Partly from having the densitometers to confirm what I'm looking at I suppose but it is quite easy to develop an eye for what's happening by looking at the low and high zones on this arrangement.
Just fer the record, Mr. Simmons and I are both ripping off Fred Picker's tried-and-true method, as first set forth in Picker's "The Zone VI Workshop" and refined over time. "Freddie's dead..."
Whatever improvement my kit has is probably its inclusion of a .1 ND filter that one places over blank film and compares to test exposures, rather than using a densitometer or sending film off to pay for someone to read it. Quick, easy and infinitely repeatable, should anyone desire to flagellate themselves with testing.
I followed it testing Tri-X, PF4, HP5 and Bergger films several years ago, and got my fill of testing. Useful but not as enjoyable as making pictures. That's why Kodak and Ilford have to stay in business. I don't want to test anymore. If they went away I'd probably have to go di-di-di-digi-...