how many stops from black to white. (spotmeter)

[Quinten]

Hello,

I've just bought a second hand light meter with a spot function. Playing around with it I wonder how many stops there are on a B&W negative. like APX 100 or Ilfords films. (from the first white to the first black)
And how many stops is the 18% gray away from these two points?

Also what do you guys usually aim for when metering this way. I read: "meter for the shadows" but even when you pic the lighter shades on a person the highlight are completely blown. (okay I could use incedent but I prefer reflected light in some outdoors situations.)

cheers,
Quinten

 

[Dan Henderson]

According to Zone System theory there are 10 stops between pure white and pure black, with each zone identified by a roman numeral. Zone I is white, Zone X is black. Zone V equals 18% gray.

To use the "expose for the shadows, develop for the highlights" theory, you "place" an important shadow area in which you want detail on Zone III. Remember that all meters, including spot meters, are calibrated to produce a Zone V reading. Therefore if you read your important shadow area, and exposed at the indicated reading, the shadows would produce as Zone V instead of Zone III, and your highlights would be blown out due to overexposure. What you do is give the shadow areas two stops (or zones) less exposure than indicated, "'placing" them on Zone III. Assuming (a dangerous thing) that your meter is accurate and the film is developed properly, there will be enough detail in the shadow area of the negative to print properly. Most zone system practitioners spend time calibrating their system and often expose at a different ISO than indicated on the film box.

If there are 5 stops difference between the important shadows and important highlights, then normal development time will produce a negative with normal contrast and be nicely printable. If there are more or less than 5 stops difference, then developing time is adjusted down or up to produce a normal negative, ergo the "develop for the highlights" part of the axiom.

 

[Soeren]

Hi Quinten
Try this link and perhaps read Ansel Adams "The Negative"
http://www.srphotography.co.uk/srpzone.html

Extract
Obviously, print values (from black to white) can be divided into as many, or as few Zones as one wishes. However, eleven is the standard by which most photographers work. This has the advantage of placing the mid-gray Zone V, the meter reading, in the middle of the scale. The Zones are numbered 0 through X. Zone 0 represents the maximum black that the print can produce. Zone X represents pure paper-base white - no image. The nine zones between are each equivalent to one increasing f-stop of exposure. Therefore, Zone III is lighter in value than Zone II, and darker in value than Zone IV, etc.

the saying is meter for the shadows and develop for the highlights.
So in contrasty situations you should develop less than normal and in dull situations you should increase development.
Søren

 

[Dan Henderson]

before someone catches my error, I reversed things in my first paragraph: Zone I is black, Zone X is white. Sorry!

 

[Soeren]

Man, am I slow

 

[Nicole]

With negative emulsion, expecially B&W, we follow the old rule of thumb: "expose for shadows & process for highlights". To expose for shadows is relatively simple, point the lightmeter at the most important shadow (making sure it's only the shadow you are metering) your meter will read the reflective light as if it were 18% grey (Zone V) and will indicate an aperture/shutter speed combination to suit. ie. 1/4sec f/8)

If you now underexpose by 2 stops (ie. 1/4sec f/16) the exposure for the shadow will move from the middle of the straightline portion of the characteristic curve to the bottom of the straightline portion, where shadows are recorded with full detail.

To process for the highlights:
Changes to development time, temp and agitation have more of an effect on highlight density than midtones and more of an effect on midtones than shadows.
You can reduce density in the highlights by reducing development or increase density by increasing development time. There is a difference to consider though between old technology films (i.e. TriX) and new technology films (i.e. Delta).

If you are taking an incident metering of a caucasian persons face, that reading will give you 18% grey again or Zone V. This will underexpose the persons face by one stop. For caucasian skin tones it's best to overexpose by one stop/expose for Zone VI.

Quinten even if you have the perfect negative with full detail, every consievable tonal range, you'll be limited to the tonal range of the paper you choose.

I hope some of this has made sense. Good luck and good light.
Cheers
Nicole

 

[Nicole]

wow, Soeren, I'm slow too! Sorry for the double up in info Quinten.

 

[noseoil]

Quinten, the important part of all of this is to remember that there is a relationship which exists between paper and film. Paper has a narrower range of vlaues than film (say 5 stops for paper, 8 for film). Film sees less than our eyes can see and paper sees less than film. The problem is taking all of that light which we see in an image and then squeezing it down so the film can place it on the paper the way we want it.

If you assume 5 stops for paper and 8 for film (I'm using zones 1-8 as a basic range of values for film, we have to start somewhere), you can see that 8/5 is the relationship between what the film sees and the paper. This is just a different way of saying that if we make a change in the film's development time to affect the highlights, it has a much bigger effect on the paper than on the film. I've been using the "Beyond the zone system" type of development this year and have found it to be a much easier way of relating light to a final print.

You might want to look at this system to see what is involved. It can get very involved and confusing, but just remember that a change in the film's development time has a big effect on the final print. My "normal" method is to place shadows on zone 3 and highlights on zone 7 in the print. This gives full values and texture for both bottom and top. I do change this in a scene if I want brighter highlights (bright cloud tops and edges) or darker shadows (very dark and mysterious areas in the print without texture). Best, tim

P.S. Zone 5 is half way between black and white (two stops below, two stops above for the print), but there is a lot of difference in how people use these values.

 

[Quinten]

Whow, quite some info in here. And I've read about the zone system but it's always hard to judge the reflection from a scene you are looking at. Above that I was confused about the 18% gray these meters measure. I figured 50% gray would be right in the middle of the film.

Anyway I might try developing a bit shorter as well to get rid of those highlights!

Thanks for all your replies!

Quinten

 

[Soeren]

Oh, another thing
You probably want to determine your personal filmspeed/metersetting to get the most out of it. Your 400 ISO films may not be 400 ISO the way you meter and you might want to set the filmspeed to corespond to the blacks/shadows.
Søren

 

[lee]

actually there is a zone 0 that is film base +fog and that gives the ultimate bleack and it goes to zone IX for paper base white.

lee\c

 

[esanford]

Whow, quite some info in here. And I've read about the zone system but it's always hard to judge the reflection from a scene you are looking at. Above that I was confused about the 18% gray these meters measure. I figured 50% gray would be right in the middle of the film.

Anyway I might try developing a bit shorter as well to get rid of those highlights!

Thanks for all your replies!

Quinten

Quinten,

You have been inundated with information... I strongly suggest that you get a copy of the Zone VI workshop by Fred Picker. It is the best, most simple and concise text written on the Zone system... It demonstrates how to efficiently find your film speed, proper exposure, and normal development time. It also helps you determine increased or decreased time. They usually sell on Ebay for a few dollars... If you can't find a copy, contact me; I have 6 or 7 copies that I am going to be using in a class that I am teaching in basic B&W photography. I will be glad to send you one for a few bucks.

Ed

 

[laz]

They usually sell on Ebay for a few dollars... If you can't find a copy....

You can go to abebooks.com and search on Fred Picker, you'll get at least a 1/2 dozen copies listed most for less than the price of shipping. I purchased one a couple of weeks ago for $2.50 (shipping $3.50).

Very decent used copy. Of course you can also go to Amazon and pay $48 new!

-Bob

 

[Lee L]

Above that I was confused about the 18% gray these meters measure. I figured 50% gray would be right in the middle of the film.

Quentin,

The amount of light reflected by things in the world on average is about 18% of the light striking it, i.e. about 18% reflectance, not 50%. Human perception is often essentially logarithmic (at least the perception of loudness and visual brightness) in response rather than linear, so that 18% reflectance seems more of a medium gray than does 50% reflectance.

Reflectance light meters are set (approximately, and this varies a little among brands) to read and place this 18% reflectance as a medium gray value. Incident meters read the amount of light falling on an object and suggest exposure based on what objects in the world should on average reflect.

Your spot meter interprets whatever it sees as being 18% reflectance, i.e. medium gray, and it's up to you to slide that up or down the scale of tones from black to white to where you want that particular object placed along the scale. That, and the capacity to change the dynamic range to some degree with development and choice of paper and paper developers, is the basis of the zone system.

Lee

 

[laz]

Quentin,
Your spot meter interprets whatever it sees as being 18% reflectance, i.e. medium gray, and it's up to you to slide that up or down the scale of tones from black to white to where you want that particular object placed along the scale. That, and the capacity to change the dynamic range to some degree with development and choice of paper and paper developers, is the basis of the zone system.

Lee

Not my thread but the above is the best description of Zone I've read! It took me quite a while to figure out that on my Zone modified meter I could just look at the zone scale on it and pick where I want the object to be!

-Bob

 

[fhovie]

Can there be anything simpler than exposure and development?

I always though it was pretty straight forward - and then - I bought a step wedge, a spot meter - started using different developers - an now a densitometer - wow. Is there anything more complicated than exposure?

For the best information on your process you would have a few step wedges and a densitometer. Short of that - a transmission step wedge can be very helpful. Try this:

1) Meter a wall at zone 5 - put your camera on a tripod - rate the film where you have been rating it (e.g. ISO 100 for APX 100) put the wall way out of focus and log on a piece of paper exposure for zones 0 through 11 - one zone on each frame. So if your wall metered zone 5 at f5.6 at 60th, zone 1 would be f22 at 125th and zone 11 would be f2.8 at 1/2 sec. So shoot your 12 frames in order.

2) develop your film the way you are used to doing it.

3) place your step wedge on the paper and see where each density prints. Expose and develop so that the clear area of the wedge is black and that the third or second thinnest density shows a slight change in blackness. Why first or second? if you are shooting film with very low base fog, the first step is likely .15 and that would imitate your film. If you are shooting a fast film and developing in pyro - your base fog could be the next step - .30. Film base fog should print black.

4) notice how many steps will print. Each step is .15 in density. The total step density for grade 2 paper is about 1.25 (8 steps) and 1.0 for grade 3 (6 to 7 steps) - Note which steps are the ends- usable densities for detail are zone 8 and zone 3.

5) compare the step wedge densities with the densities of your film. You will not get the data that a densitometer will give - but your eye is incredibly sensitive and can tell you accurately which densities match. - note the span. Each step is .15.

6) You can now tell how many stops your film recorded by multiplying the number of steps by .15. You also know what your paper will print.

What you can do with this information is
1) know your true film speed - since you did zone 0 and zone 11, you can see where your first change in density was. If you can see a density difference between zone 1 and base fog - you are correct on your film rating and your zone 5 is somewhere between .5 and .7 density. If your zone 2 density is the first change off base fog, you might need to rate your film speed at 1/2.

2) know your contrast range. One goal of many photographers is to spread the available contrast over the entire range of the paper. If you meter 5 zones, you may want to develop so that only five SBR (Scene Brightness Range) will print over the whole density of the paper. If you keep track of each film test - you can build a library of times and density ranges that can be used for each scene (or group of scenes for roll film) So you can know that at 8 minutes you get 8 zones over a DR (density range) or 1.25 - That range is from the first step that shows a difference in printing to the last step that shows a difference in printing - over base fog. You might see that at 11 minutes you get 5 zones spread over a density range of 1.25.

If I am shooting with available light indoors or if I am shooting sand dunes, I will not see a SBR over 5 zones. I will need to develop longer to strech the contrast over the paper and will need to under rate the film to add this development time to expand the contrast. So low contrast - film gets faster - develop longer. I go to the charts I have made and chose the developer and film that works the best.

If I am shooting landscapes with deep shadows at mid-day - (I cry) then I under rate my film and under develop so I can get that huge SBR - 12 stops or more to fit in a film DR of 1.25.

Having a spot meter means you have graduated from the process of looking at the average of available light and trying to pin zone five at a density of .6 and now you ar looking at the edges - zone 3 and 8 and trying to get them in the DR of your film based on the paper you will use. It takes a long time - a lot of film and chemicals - and a lot of work to get good at this. - At least it did for me. But! now I seldom miss on exposure and when I print in the darkroom - most negatives are straight prints. There are still some that require burning and dodging but paper exposure times and development times stay constant because each frame is fitted to my process.

 

[highpeak]

Sorry for hijack this thread, but since we are on the topic, I just want to know what is the 8 on the pentax spot meter(not modified) means according to zone value? Is it Zone VIII?

Thanks

 

[Claire Senft]

There are about 4 1/2 stops of difference from the blackest black and the whitest white that can be found in paint. To get more range than this requires the addition of difference between highlight and shadow.

 

[Quinten]

Ohh dear, I gues one can makes these things as complicated as you want. So for now step by step and playing around seems best. A lot of great suggestions to keep me bussy wich I am very thankfull for.

I already did test my films but it's always a bit random since it's the human factor that decides where to point the meter.

Above that: one step in the zone system is not the same as one f/stop???

cheers,
Quinten

 

[BradS]

before someone catches my error, I reversed things in my first paragraph: Zone I is black, Zone X is white. Sorry!

You can edit the original post. This help folks later when searching and reading posts out of context.

BTW: that is the clearest, most concise explanation of the fundametal tenents of exposure using the Zone System I've ever read/heard. Thanks.

 

[Lee L]

Above that: one step in the zone system is not the same as one f/stop???

One f-stop in the Zone System is equal to one Zone with "normal" development and printing. If you vary from "normal", the Zone System allows you to predict how much to compress or expand the dynamic range of the film to fit the subject and get everything you want onto your print. This compression or expansion is done with appropriate choice of filters, film, pre-exposure, developers, developing time, paper, paper grade, paper developer, etc. In other words, all the variables in the process.

Lee

 

[john_s]

As we've seen, there are a number of ways of saying more or less the same thing. They all make sense, and they are consistent with each other. I like fhovie's aproach because it is linked to the paper/film combination, which is what we're aiming for. Just a little caveat about step wedges: they are not all in 0.15 steps. I have a Stouffer one in 0.1 steps. This gives better resolution at the expense of a smaller range > leading to having to be more accurate when selecting an enlarger exposure, since one can "go off the scale" more easily.

 

[noseoil]

Quinten, in my post I tried to address the relationship of exposure and printing. Everyone does things differently. I have used the analogy of 8/5 (film to paper relationship), so one f-stop of increase in exposure would actually be about 1.6 stops of increase on the paper in a print. You can see how this increases faster on the paper than it does on the film if you do a shot and bump things a full stop. What is a metered f-stop will give a bigger jump on the print.

Claire mentioned that paper sees only about 4 1/2 stops of real values (I use 5 as an easy number), so it is very narrow compared to what film can see and deal with. Just because it is on the film, doesn't mean the paper can deal with the contrast. tim

 

[Quinten]

Just recieved a pm from Ornello (I hope you don't mind me posting this here otherwhise just ask me to delete it.)

"It has nothing to do with zones. The number of stops from black to white depends on the total gradient of the film and paper and upon nothing else. A hard negative of a given scene can be printed on soft paper and a soft negative of the same given scene can be printed on hard paper and you would end up with the same scale of tones. A hard negative printed on hard paper may have only three stops from black to white, and a soft negative printed on soft paper may have neither black nor white."

Okay even if there is only Black and white without grays on a film it would still be the same amount of stops if I understood everything right, but the rest of the pm might be a nice addition.

cheers and thanks to all who responded here, it has been a threat with many lessons!

cheers,
Quinten

 

[Kirk Keyes]

Can there be anything simpler than exposure and development?

I always though it was pretty straight forward - and then - I bought a step wedge, a spot meter - started using different developers - an now a densitometer - wow. Is there anything more complicated than exposure?

That's a great paragraph there!