In Adams book "The Negative" he shows on page 50 a series of zone patches which are photographs of a piece of hardboard. This quick methodology gives you a suggested starting point tells you how to work out your EI and dev time for the zone system without resorting to sensitometry.
So Look at Adams The Negative on page 50, read what it says and reproduce those test patches yourself and actually print them for the visual proof.
As a starting point use half the film ISO speed, use a standard developer and reduce the recommended dev time by 30%. You may need to tweak that but start at 30% reduction of recommended print time.
When you do your printing of the test patches, use the zone 1 negative to determine print time. Produce a test strip from it until you find the step which produces the first perceptibly lighter than black step (after dry down). Then use that time to produce each of zone 0 thru 10 patches.
Notes:
Go enjoy and don't let the people with their sensitometry agendas ruin your day. None of it is necessary if you follow this practical evaluation methodolgy to finding EI and dev time for zone system.
OK so if you want to go down the sensitometry route then you can but not without a densitometer and it won't make your photography any better or more accurate than the above. And remember what John Sexton is quoted as saying: "It's a zone system and NOT a pinpoint system".
So Look at Adams The Negative on page 50, read what it says and reproduce those test patches yourself and actually print them for the visual proof.
As a starting point use half the film ISO speed, use a standard developer and reduce the recommended dev time by 30%. You may need to tweak that but start at 30% reduction of recommended print time.
When you do your printing of the test patches, use the zone 1 negative to determine print time. Produce a test strip from it until you find the step which produces the first perceptibly lighter than black step (after dry down). Then use that time to produce each of zone 0 thru 10 patches.
Notes:
- Put camera about 6 feet from a piece hardboard (or textured wall such as rough rendering or possibly brick wall but we are looking for some texture in it) so hardboard fills the frame. And focus on hardboard accurately. Hardboard must be evenly illuminated and texture in it visible. Light must stay constant during the test which should be done in daylight.
- Meter hardboard and close down 5 stops and expose. Then open up 1 stop and expose. Repeat until you have exposed at all zones upto and including zone 10. So you will have 11 negatives zone 0 thru zone 10.
- Paper max black obtained in a normal print is not as black as the paper will actually go if you over print it. It is for this reason you MUST NOT use the zone 0 negative to work out print time for each patch. Adams uses zone 5 negative to get print time. I strongly recommend using zone 1 negative (We are not trying to reproduce a gray card on zone 5 by doing this test so don't try).
- When you print each patch you really should use the exact same print exposures you used in the test strip of the zone 1 neg. e.g if you used 8 1 second exposures to find the step then you should use 8 1 second expsoures to print each patch.
- I would print the patches using your preferred paper and developer and use NO FILTRATION. However, you may find its better to use your Y+M grade 2 setting if you are not intending to use Ilford filters for printing later on. I strongly recommend the use of Ilford filters for ease of printing.
- If you find the zone 10 patch print has some tone in it then you will need to increase your neg dev by another 10% next time. If you find your zone 9 neg has no tone in the print, then you will need to reduce your neg dev by another 10% next time, so by 40% of manufacturers recommended time.
- When inspecting your negs, the zone 0 neg should have a small tad of density above fb+fog density. If it does not have density above fb+fog then reduce your EI by another 1/3 stop next time. So if you were using 400 film and started with 200, then use 160 next time.
- That just about covers it. You'll learn a lot by doing this. Not only what your EI is but also confirm your development time is correct for a 10 stop SBR range as the zone system teaches. And be able to see that what is being taught in the Zone System is actually happening. i.e. full textural detail in zone 3 and zone 7 etc.
- What you need to know is that the typical closed subject (no sky) is less than a 10 Stop SBR, maybe only 5 to 7 stops of SBR. However it is simple to increase printing contrast to produce a print with some bite in it from a slightly soft negative. Much simpler than trying to take contrast out of an overly hard negative, so 10 stops range is good as it covers most scenarios even though it may give slightly soft negs depending on SBR.
- The beauty of doing this totally practical evaluation is that it is calibrating to your meter, lens and shutter all in one go so you don't have to worry about any of the usual stuff that people like to throw in to complicate things such as flare and densitometry. Also, for the vast majority of your shots you will have some lens extension and focussing from 6 feet will include that in your calibration so you don't have to consider it when out in the field. If you do happen to focus further away when you are out in the field then you will get a tad of extra exposure which won't harm at all and in fact gives a small safety margin to guard against underexpsoing zone 0.
- Finally when in the field with your trusty spot meter, meter and expsoe for a highlight and not a shadow. Use a zone 7 or 8 highlight. Only meter and expose for a shadow if the subject brightness range is greater than 10 stops. Doing this will make your printing much easier allowing you to increase print contrast without fear of blocking shadows, epsecially if you are using Ilford print contrast filters.
Go enjoy and don't let the people with their sensitometry agendas ruin your day. None of it is necessary if you follow this practical evaluation methodolgy to finding EI and dev time for zone system.
OK so if you want to go down the sensitometry route then you can but not without a densitometer and it won't make your photography any better or more accurate than the above. And remember what John Sexton is quoted as saying: "It's a zone system and NOT a pinpoint system".
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