Question On Subject Brightness Range

[Peter De Smidt]

When the Zone System was formulated, nothing about sensitometry changed. What worked before still worked after, and there are a ton of different ways of getting where you need to be to get what you want out of your photos. For instance, if you use Mortensen's techniques, i.e. lighting, development, and appropriate film...., then "exposing for the highlights and developing for the shadows" (Mortensen On the Negative), the opposite of Ansel's maxim, will work fine. If you photograph scenes with important shadows, it will not work fine The important thing is to try what seems best to you, evaluate the results, make changes......

There seems to be a lot of animus against "The Zone System". It's hard for me to understand. In the first place, there are lot's of alternatives. So, which system is the problem? Adams? Minor Whites?.... And then there are people who treat general pronouncements as if they were categorical imperatives. Usually, they're not. You don't have always put a detailed shadow on Zone III and a detailed highlight on Zone VIII. That's just a starting point. If you read Adams, he stresses the importance of visualization (knowing what you want to get), and then applying systematic steps to achieve that end. If a visualization is better achieved by different placement, well, then so be it.

What's really nice about the Zone System is the terminology, as how we photograph revolves around f-stops, and so it's very natural to think in those terms. For instance, many years ago now I switched from a regular timer to an f-stop timer. It lead to a big improvement in my printing, as I could ignore times and concentrate on stops (or zones.) This doesn't put a straight jacket on technique. It just provides a useful way to think about print exposure.

Getting back to photographing, if I'm using a tripod, I'll use a spot meter, read the values, and decide on a placement. Given my visualization, I'll decide on a method of development, mainly a normal one, but occasionally a +1.5 or divided development. So I use some of the testing and terminology of the zone system. What's wrong with that? It's what works for me. If something else works for you, then by all means carry on.

[Bill Burk]

Response to Pere Casals... It's almost that simple. The shadows are hard to predict or nail down when you take a picture.

Every kind of scene has a different amount of flare. For simplicity I just use the average flare 0.4

[Pere Casals]

When the Zone System was formulated, nothing about sensitometry changed.

I completely agree. The Zone system is abaut spot metering, because one relates the metering of every area to resulting densities in the negative. Ansel never told if a photographer should place an scene area in a zone or another, he simply described how consistent areas end in particular negative densities after a particular +/- processing, and that what's in toe/shoulder get crunched.

IMHO the mess comes when a simplified metering system recommends an exposure from averaging things. An incident light system don't tell if we are to have detail in the scene shadows...

Response to Pere Casals... It's almost that simple. The shadows are hard to predict or nail down when you take a picture.

Every kind of scene has a different amount of flare. For simplicity I just use the average flare 0.4

Yes, this is true, IMHO shadows have 2 problems, one is the unknown flare amount, the other (for long exposures, not that uncommon) is LIRF, as shadows have more LIRF...


I found very useful to meter by using the SLR (Nikon F5 in my case) spot meter. I found a multicoated prime SLR lens working very similar than an LF lens, same transmission and same scene depending flare. Sun in the framming will cast aprox same flare on the shadows in the SLR metering system than the LF lens, so metering is pretty accurate.

Another way I found is using a fixture to place the SLR in place of the ground glass, without the SLR lens, so in fact I have a TTL metering for the view camera, with the rise/shift I can explore all the scene with a TTL spot meter...

The other important thing I found important is testing LF shutters, IMHO it is the greatest factor for uncertainty in a LF shot, at least with my beaten shutters...


... It weights a lot, but if one has to kill an agressive bear, the F5 also is always an effective weapon

[Stephen Benskin]

Ok, I'll wait for your comments later...

But let me point something... (talking for Normal development, for ISO calibration)


The "n point" in the ISO rating is at 1.3 Log H from the toe.

In this document http://www.apug.org/forum/index.php?...ure-pdf.23850/ the meter point is at 1.25 Log H from the toe, just 0.05 difference, this is 1.8-0.55 = 1.25

So the meter point ("a" in the 1960 document) and the (ISO procedure) n point are the same irradiance (1/6 stop difference, perhaps)


Attachment 166012


But I don't know if the meter point changed after 1961 new rules...


My guess (not sure) it that yes, it changed, so under present specifications we should have 3 linearly underexposed stops plus toe, if toe takes one stop then we should have 4 underexposed stops, with some toe detail at -4. And -5 should be pure black. This is the same than with zone system gray levels...

If I'm right (not sure) since 1961 the "n point" of ISO rating is at 0.3 Log H at the right of the C point of the 1960 graph. Simply the C point moved an stop (0.3H) to the left because 1961 rules doubled on box speed...

Pere, where to start. First, think of the parameters of the ISO speed graph as no more than how to determine a gradient, not unlike other methods like Contrast Index or average gradient. All three are a way of determining or defining contrast, not exposure. Once the film conforms to the ISO contrast parameter, the ISO speed can be determined; however, it still doesn't say anything about exposure. On the other hand, your other example comes from the paper Safety Factors does. It illustrates the average scene and it's placement based on the old ASA speed derived from the fractional gradient method. The "speed point" in that example is the fractional gradient speed. Jack Dunn has a similar diagram based on the post 1960 ASA standard.



And one I put together.



A number of years ago, I put together a document titled "Defining K." It explained the process from light source illuminance to tone reproduction, focusing mostly on exposure theory. The .pdf is too big to upload here. I can email it if anyone wants. The original thread is over at APUG somewhere.

And here is an example of the camera image and it's relationship to the negative for zero flare and one stop flare scenarios.



I don't want these posts to be too long. Next one will be on exposure.

[Vaughn]

I've found Ortho+ pretty easy to control - that said, the ability to fairly easily DBI the stuff is handy...

What are you developing it in?

Ilford PQ Universal Developer in a 3006 Jobo Expert Drum. This last batch was developed at 1:19, 68F, 5 minutes. I found that 1:19 is working out nicely for me. I started off trying 1:9, but had to back way off. I just jumped in with both feet, and am not too surprised to end up with dense highlights! Some of the negatives will print well in Platinum/palladium (I generally do not use contrast agents).

It feels like I'll be able to get repeatable usable results with this combination. It might be fun to give it a try in a Pryo developer, but I think I'll try to keep it simple!

[Pere Casals]

I don't want these posts to be too long. Next one will be on exposure.

OK, thanks in advance, I'll wait for that...



Anyway this graph:

Jack Dunn has a similar diagram based on the post 1960 ASA standard.

...Says we have 10x from photometer point to the left, where toe starts crunching. That 10x is 3.3 stops, so areas beyond 3.3 underexposure are in the toe, not in the linear part of the curve. So from film ISO calibration and a spot photometer reading, with "normal" development, we know if an scene spot is in the toe or not.

If we use an SLR as a TTL spot photometer it will include similar flare than the LF lens, is both lenses are consistent (SLR is a multicoated prime, and LF lens is also MC...).

The flare impact graph sample is very interesting... it tells about the importance of flare... and comparing both one can guess how shadow microcontrast is lowered by flare.

I guess the way to recover shadow microcontrast in the darkroom should be SCIM masking...




I think this is useful for knowing what's in the linear part and what's in the toe, anyway determining the exposure/process for our visualization should be more complex, I'm sure your next post would enlighten that, thanks in advance.

[interneg]

Ilford PQ Universal Developer in a 3006 Jobo Expert Drum. This last batch was developed at 1:19, 68F, 5 minutes. I found that 1:19 is working out nicely for me. I started off trying 1:9, but had to back way off. I just jumped in with both feet, and am not too surprised to end up with dense highlights! Some of the negatives will print well in Platinum/palladium (I generally do not use contrast agents).

It feels like I'll be able to get repeatable usable results with this combination. It might be fun to give it a try in a Pryo developer, but I think I'll try to keep it simple!

PQ Universal & O+ user here too - mainly for masks, & ID-11 for more 'normal' contrast work on silver gelatin. PQU at 1+9 can be pretty intense on film, unless you're going for printing-out materials. Your times sound about right for platinum/ palladium relative to Ilford's suggestions for 1+19 times in PQU (4m at 20c for a G-Bar of 0.62) - glad it's all getting under control!

[Stephen Benskin]

Sorry, I spent around two hour writing a post and when I went to upload it, the site had logged me off and I lost 95% of it. All that survives is the bit of intro below. Not really in the mood to redo tonight.

For any speed or contrast methodology to be relevant, the psychophysical nature of the photography must be considered. This is what Jones did in with The First Excellent Print test. He established a criterion of excellence for the photographic image, and established the definition of exposure.

Jones concluded negative density is not a practical criteria for determining quality. Contrast is, or more accurately, film gradient. More specifically quality is determinant by the gradient of the toe in relation to the overall gradient of the film. This conclusion came after comparing various speeds methods with the test print judgement speeds under the greatest number of conditions with the greatest number of emulsions and degree of processing to determine the method that most accurately corresponded to the results from the prints judged to be excellent.

[Bill Burk]

I found a spot meter that has 0.4 flare similar to the camera image, so I agree your meter might already help you integrate flare into your readings. In practice, you might compensate for "already-included" flare by simply placing the shadow reading a stop higher than you otherwise thought, for instance on Zone IV instead of Zone III*. I wouldn't bother over that last third-stop at this point.

The 3 1/3 stops down to the speed point is sensitometric exposure as opposed to what you get in the camera-image.

*Maybe the switch in practice from close-up reading with Weston Master meters to camera-position spotmeter readings had something to do with the change from Zone II shadows to Zone III that I noticed between older references and more up-to-date ones. (So if you use a Weston, place in Zone II or III... if you use a spotmeter place shadows in Zone III or IV).

[Peter De Smidt]

Just something I learned the hard way, if you're going to write a long post, it's best to write it in something like Google docs, cutting and pasting onto the forum.