Step wedge film test question

[k_redder]

I was looking to revisit my film testing using a different approach than I had used previously and I wanted to use a step wedge (like the one below) to relate densities to actual print values that I get with my "system" (equipment, materials and methods) and I have a couple of questions that I'm sure someone here can help me with. First off, this step wedge is in increments of .15 which allegedly represent 1/2 stop each. If I was to put this in my enlarger and print it using a "Normal" (grade 2 filter) so that Step 2 shows the slightest bit of value above pure black (making that Zone I), should I expect to find a Zone IX print value (last noticeable value before white paper base) at around Step 18?
I have a bunch of other questions, but I'll ask them in subsequent posts (if there are any). Thanks in advance.

[203Ektar]

I was looking to revisit my film testing using a different approach than I had used previously and I wanted to use a step wedge (like the one below) to relate densities to actual print values that I get with my "system" (equipment, materials and methods) and I have a couple of questions that I'm sure someone here can help me with. First off, this step wedge is in increments of .15 which allegedly represent 1/2 stop each. If I was to put this in my enlarger and print it using a "Normal" (grade 2 filter) so that Step 2 shows the slightest bit of value above pure black (making that Zone I), should I expect to find a Zone IX print value (last noticeable value before white paper base) at around Step 18?
I have a bunch of other questions, but I'll ask them in subsequent posts (if there are any). Thanks in advance.

Check out this YouTube video from the View Camera Store. I think it is just what you're looking for.

[k_redder]

Check out this YouTube video from the View Camera Store. I think it is just what you're looking for.

Thanks for the link. What I'm really trying to do is find a target density to shoot for in my film development testing. Here's a scenario.... let's say I decide to target a Zone IX density to do my film testing around (see here: http://www.alanrossphotography.com/2...x-calibration/ )....
Now let's say I print the step wedge as described (using #2 filter) where step 1 is printed as pure black (Zone 0) and step 2 shows the first hint of value above black (Zone I). When I do this, the last bit of value before pure white paper base (Zone IX) appears at step 14. It seems to me that whatever density exists at step 14 (above fb+f) is the density I need to achieve in my negative to produce a Zone IX value when printed. This seems to make sense to me, but based on this I need a density of 1.95 (13 steps x .15 ea.) to get there. If true I am fine with that, the reason I hesitate is that 1.95 is quite a bit higher than the Zone IX density shown in Alan Ross' charts (at link above) or any of the exposure/density curves in Adams "The Negative". So either my "system" of methods/materials/equipment is that much different than most, or I am going off the rails somewhere.
For those that might be curious, the "system" consists of: Beseler 45MXT w/ Aristo V54 Head, No. 2 Ilford MG filter printed on Adox MCC110 developed in Dektol 1:2 for 3 min. Anybody have an opinion?

[Bill Burk]

1.95 is quite a bit higher than what is usually recommended for Grade 2. I'd be looking for 1.00 to 1.20

Do you have a safelight issue or light leak that gives "more" light to the paper than expected?

Do you normally get very flat prints with the Aristo head? (I have an old greenish Aristo that gives me lower grade than expected with MG paper).

If these aren't the issues, then maybe it's just the difference between standard way of choosing (90% black and .04 white) aims versus your "eye match" method.

[Bill Burk]

This could also be since you are looking at Zone IX where I might be looking at 7 2/3 stops... Even Minor White looked for 1.5 at Zone VIII

[nolindan]

Grade 2 paper has about 5 stops (1.5 OD) of exposure range between black and white. Its contrast in the middle of the HD curve is 0.5 stops of exposure (equivalent to 0.15 OD) per print tone zone.

Since the tail and shoulder of the HD curve are flat it can be really hard to judge where the 0.04/2.0 densities are. This makes it hard to judge a paper's white-black range. And any way, it isn't the paper's white-black range that's important but its ZII-ZVIII range that has to fit with the negative. You ooch things around to get the highlights to look right and dodge/burn the shadows as needed (or vice versa, or both).

You should also realize that your enlarger contributes a significant amount of flare. If you are interested in finding your paper's range then you need to do your tests by contacting the tablet. You should then get more contrast from the tablet and get closer to 10 wedge steps.

As to what density you should develop your film to - the answer is what ever density pleases you. There is no magic number. A lot depends on your aesthetic, what subject matter you shoot, how much flare your enlarger produces, what paper you like to use, how long you like to develop your prints, your toning procedure and where your prints are exhibited.

There is too much emphasis on numbers in the current interpretation of the ZS. First you find how to make a negative that makes a print that pleases you. Then, if you are so inclined, you can take the process apart to find the relationship between negative exposure and negative density - though frankly, IMO, there isn't much to gain from it.

As has been noted before, the ZS boils down to:

Sunny and very bright: Overexpose 1 stop, under develop 15%
Hazy to middling: normal exposure and development
Cloudy and dull: underexpose 1 stop, over develop 15%

As to my personal EI and all that: after 50+ years of taking pictures, developing negatives and making prints I have found that Kodak is dead-on when it comes to film speed and development. If things aren't coming out right then it is my technique that is to blame and that is what needs changing - not the film's speed or developing time.

I'm an Engineer, and as such I'm a professional measurement and calculations geek. But I now leave the spot meter at home and concentrate on seeing. I leave the spot metering to the darkroom - it saves on paper. Different strokes for different folks.

Disclaimer: I am the head of Darkroom Automation, so my views on the matter have a certain prejudice that you should take into account.

[Chuck P.]

Thanks for the link. What I'm really trying to do is find a target density to shoot for in my film development testing. Here's a scenario.... let's say I decide to target a Zone IX density to do my film testing around (see here: http://www.alanrossphotography.com/2...x-calibration/ )....
Now let's say I print the step wedge as described (using #2 filter) where step 1 is printed as pure black (Zone 0) and step 2 shows the first hint of value above black (Zone I). When I do this, the last bit of value before pure white paper base (Zone IX) appears at step 14. It seems to me that whatever density exists at step 14 (above fb+f) is the density I need to achieve in my negative to produce a Zone IX value when printed. This seems to make sense to me, but based on this I need a density of 1.95 (13 steps x .15 ea.) to get there. If true I am fine with that, the reason I hesitate is that 1.95 is quite a bit higher than the Zone IX density shown in Alan Ross' charts (at link above) or any of the exposure/density curves in Adams "The Negative". So either my "system" of methods/materials/equipment is that much different than most, or I am going off the rails somewhere.
For those that might be curious, the "system" consists of: Beseler 45MXT w/ Aristo V54 Head, No. 2 Ilford MG filter printed on Adox MCC110 developed in Dektol 1:2 for 3 min. Anybody have an opinion?

I recommend this book to you. It will help you in testing your paper with the step tablet so that you can determine the "relative" iso range number------the RN determines the contrast grade produced by a particular contrast filter in combo with your paper developer and any toning that you may do. BUT! Not all contrast filters produce a significanly different range number i.e., a #2 filter may not provide much of a difference than a #1 for example. Paper testing in this book lets you know which contrast filter provides a range number that is equivalent to a grade 2 paper contrast, which is a RN of 95 to 115, or dividing by 100 to get the paper's exposure scale value, or log exposure value---.95 (a hard grade 2) to 1.15 (a soft grade 2), the middle of that range is 1.05.

.95 to 1.15--------in theory, a negative with a contrast range (from Zone I to Zone VIII if your're into AA's The Negative) between .95 and 1.15 would seemingly be a perfect match for the range of "normal" grade 2 print contrasts. However, in practice there is some degree of enlarging flare, which means that the image on the paper will be lower in contrast than the image on the negative (unless you are contact printing). So the question is how much additional contrast do you provide to the negative to make up for losses due to enlarging flare. A flare factor of 2, i.e., one stop, i.e., 0.3 log exposure is entirely possible, maybe you think it is only 2/3 of a stop, then use 0.2. Therefore, If you wish to use the middle of the grade 2 range numbers as your starting point, then a negative density range of 1.05+0.3= 1.35 is needed. Perhaps you like the soft end of the grade 2 range, then, .95+0.3 = 1.25.

The You Tube video was fine but it did not tell you how to read that test, IMO. The book I suggest will show you how to do that. In short, you count the number of steps showing tone (don't count step 11 twice though) and then refer to a table in the book for a 21-step tablet that gives the RN based on how many steps you counted. Ex: you may find that your filter #3 has 7 steps of tone, the RN is therefore 95 or a .95 log exposure value-----now you know that your #3 filter (with your paper, paper developer, and toner) is actually only providing a contrast grade of about a hard grade 2. I find that it works nicely.

[Cor]

If you are interested in finding your paper's range then you need to do your tests by contacting the tablet. You should then get more contrast from the tablet and get closer to 10 wedge steps.

Hope the OP does not mind a little bit of hijack on his thread. Just last night I was using a stepwedge to test contrast (I have still 2 boxes of Forte Fortezo in the fridge, although labelled Normali (normal) give harder images than normal I thought: checking with a 21 Stouffer stepwedge I ended up with 9 discernible steps versus 12 discernible steps for Ilford Mg IV FB.)

Anyway I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

thanks,

best,

Cor

[nolindan]

Bruce Barnbaum [wrote] ... "when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge" ...

Why?

The biggest reason is flare in the enlarger.

The second reason is stray light that bounces from the illuminated parts (shadows) of the projected image, on to the walls and ceiling, and and then back on to the paper.

This doesn't affect shadows at all but can take a 1/2 to 1 stop off the highlights. This isn't a big deal in practice as it essentially does an automatic flashing exposure resulting in increased highlight detail. The same effect happens in a camera, where the flare helps lift the shadow exposure up off the toe of the film curve.

A little bit of flare is a good thing.

[Ken Lee]

I was reading Bruce Barnbaum's book "The art of photography"were he mentioned (if I quote him correctly) that when using a condensor enlarger the contrast of a projected stepwedge is not the same as the contrast of a contact printed step wedge using teh sme enlarger and same filter.

Why would that be?

Although there's some disagreement about it, the Callier effect causes condensor enlargers to yield blocked high values - particularly when compared to cold light enlargers or contact printing. This was nicely documented by Fred Picker in his book Zone VI Workshop.

At the time when those tests were done (1971), the Caller effect was already well-known.