As I suggested in an earlier post, the Zone VI Pentax spot meter might have influenced your conclusions. Mine gave me similar results that did not coincide with all other meters. My two are for sale, if anyone wants inaccurate meters.
After reading your post I've just gone outside and checked my spotmeter against a fairly new Sekonic L-308S. We have a cloudless blue sky here today and the meters agreed perfectly, (metering the blue sky), I then metered a dark card in open shade, again the meters agreed. Maybe your meters are defective but mine appears to be working perfectly.As I suggested in an earlier post, the Zone VI Pentax spot meter might have influenced your conclusions. Mine gave me similar results that did not coincide with all other meters. My two are for sale, if anyone wants inaccurate meters.
The film was hand developed in D76 1:1 for 9 minutes, 30 second agitations.
That's a slightly insulting question, having developed films for 40+ years including 10 working in a pro lab. I live in Australia where it is the middle of summer although I'm not sure what the season has to do with film development temperature. I measure film developer 3 times, once just before it goes in, mid way through development and then after it is poured out, the drift is usually 0.5 Degree C.
As I suggested in an earlier post, the Zone VI Pentax spot meter might have influenced your conclusions. Mine gave me similar results that did not coincide with all other meters. My two are for sale, if anyone wants inaccurate meters.
After reading your post I've just gone outside and checked my spotmeter against a fairly new Sekonic L-308S. We have a cloudless blue sky here today and the meters agreed perfectly, (metering the blue sky), I then metered a dark card in open shade, again the meters agreed. Maybe your meters are defective but mine appears to be working perfectly.
Very Very True!Yes but usually you leave that whole a lot smarter than you entered it.
Technically, LV, not EV. A scene (object+lighting) spot has a definite LV (luminance). Which corresponds to diverse EV values (speed-diaphragm combination) depending on the film speed. The two coincide numerically for ISO 100 film.the blue sky in New Mexico is EV 14 and my hand is EV 15
Except OP was satisfied with his negatives up until tests second guessed that. Not that negatives prior to that changed in the sleeves. And OP still stated he was not going to change anything. But with all follow up posts he ma have no choice. Seems like sure way to take all the fun out of shooing pictures.I don't know about your meters, but all three of my Pentax digital spot meters (modified and unmodified) have fairly significant flare that will skew the meter reading for a dark object when there are brighter things around. This could easily be the cause of the underexposure the OP has. I have to be careful of this in the field, often compensating for possible flare by adding a bit of exposure. A lens hood on the meter helps a bit, but doesn't solve the problem entirely. FWIW, my modified meter tends to flare more than the unmodified (maybe all the filters added scatter more light?).
There are a number of other things that might influence the test results as well: faster shutter speeds than expected, inaccurate densitometer readings, development times that are on the short side, developer exhaustion or formulation not as expected (e.g., I had a batch of PMK that was inexplicably weak for no apparent reason), etc., etc.
My advice would be to err a bit on the overexposure side, go out and make some exposures and see how they print, paying special attentions to the shadow detail desired. Basing exposure on a Zone III or IV placement is a lot different that metering for Zone I and eliminates a lot of the flare problem.
I used to do a lot of film-speed testing, but these days just rate my film 2/3 stop slower than box speed to start, keep good notes and modify as I go. More important is finding a good "normal" development time that allows the maximum contrast control in the darkroom. Again, keeping notes and adjusting as I go works well for me.
Best,
Doremus
There are some exceptions to the EI/ISO problem, however this is because the manufacturer misuses the ISO designation.
Some of the Foma films, for example. They are branded as ISO xxx however the data in the technical sheets contradict this. They also clearly mis-label EIs as ISO in these documents.
Oh please, grace us with your method for finding your EI. Or is it just "sunny 16 rule" for you and hope for the best?Hard to believe people used to think this method of testing produced "true" speeds.
Used to? Many people still do. And it goes further than that. They still believe finding this EI is critical to improving print quality. Further still, they believe minus/plus development is a much more effective control than it really is, in the context of print quality. Basically, people see what they want to see.
There are some exceptions to the EI/ISO problem, however this is because the manufacturer misuses the ISO designation.
Since there are tons of photographs printed with great brilliance and detail (which is what ZS user are after), but with no testing of any kind, how does that fact tie into the need for all testing, targeted development etc.? I have no problem with anyone who wants to spend all that time on testing rather than actual photograph making, but I see your thread here showing the exact dangers of not seeing that others are able to do without.Well it sort of is crucial for print quality. Not giving enough exposure, which will almost certainly occur if you rate TX @400, will result in shadows that print pure black. If that's your cup of tea, go for it!
Regarding plus or minus development, not long ago I had a very low contrast scene, I exposed two sheets. The sheet that got 25% more development printed much better than the one that got normal development. I'm glad you are so happy with your film exposure/development regime, but there is no need to poo poo others methods, whatever works for you.
As I suggested in an earlier post, the Zone VI Pentax spot meter might have influenced your conclusions. Mine gave me similar results that did not coincide with all other meters. My two are for sale, if anyone wants inaccurate meters.
Oh please, grace us with your method for finding your EI. Or is it just "sunny 16 rule" for you and hope for the best?
I will explain what I learned from Stephen.Oh please, grace us with your method for finding your EI.
@markbau let me introduce my good friend Stephen Benskin. His background is as consultant for photolabs in the Los Angeles area during film’s heyday. He knows how to get good lab control.If you want to know how I do it, you can search the site for my posts. I use a sensitometric approach and have written extensively about it.
Doremus and others, per meters. Flare is easily controlled. You can put a rubber lens shade on a Pentax spotmeter just like a camera lens. It's an odd but available size, 40.5mm if I recall correctly.
I will explain what I learned from Stephen.
For film with unknown properties (e.g., Tri-X expired in 1974)… Expose film on a calibrated sensitometer and develop to ASA parameters. Index to the exposure corresponding to density 0.1 above base plus fog.
For fresh film, trust the speed indicated by manufacturer. Develop to ASA parameters and calibrate the sensitometer to the density 0.1 above base plus fog.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?