TMY-2 /Pyrocat Film Speed test results question

[gphoto120]

Every film speed test procedure I've read seem to indicate that "usually" the results are box speed or slower. Ex. 400 speed tests at 320,200 or 400. My tests indicate my film speed to be 800. I've dev. 2 rolls with the same results.
My procedure is per Bruce Barbaum's - I stop down 4 stops, 5 stops and 3 stops. the closest frame to film base fog is the 5 stop exposure. ( I have used 2 different lenses as I have a Kowa 6 w/ leaf shutter and wanted to see if any difference in lens) Both produce very similar results. Maybe I'm concerned over nothing??..I haven't gone any further as I thought maybe I'm making an error?
I'm shooting TMY-2, agitate first 30 sec. and 10 sec. every 3 min. pre-soaking, dev 15 min @ 70deg., stop/water, fix in T4 and wash.
Any comments are welcome!

 

[jgjbowen]

The reasons for your results include, but are NOT limited to:
shutter speed
meter accuracy
processing methods
developer

I'm sure there are more, but those are what occurred to me. That's why they call it your PERSONAL film speed.

If you shoot at 800 and make good negatives then don't worry about it. If you shoot at 800 and don't make good negatives then adjust as necessary.

 

[c6h6o3]

My procedure is per Bruce Barbaum's - I stop down 4 stops, 5 stops and 3 stops. the closest frame to film base fog is the 5 stop exposure.

Of course it is...it received the least exposure. You're just proving an axiom with such a "test". What does it tell you about how to expose negatives so as to yield the best print? Absolutely nothing.

Bruce is a fine photographer, but I have always disagreed with him (and Ansel Adams) about this procedure for determining film speed. There will never be a Zone I in your pictures. Zone II maybe, but it will (and should) have no detail. What I've found to be the optimal film speed, for any film/developer combination, is that speed which (if we must speak sensitometrically) gets Zone III onto the straight line portion of the curve. In other words, a speed that allows you to know from the slope of the curve what the effect on the density will be for a given adjustment in exposure. Or in more photographic terms, a speed that yields good shadow detail.

I recently saw some stunning prints by a well known large format photographer. These were among the finest prints I'd ever seen, by anyone. The negatives used to make them had a base fog of between .3 and .5. (And no, that's not a typo. I don't mean .03 or .05). He just prints through the fog to achieve a magical effect. He knows his materials and is a master printer.

 

[MVNelson]

your next step is to use the same process and shoot a some photographs at that film speed and print negatives. Do your self a favor and simultaneously shoot at 1/2 your "tested" film speed (400), and compare the results. With the risk of influencing things too much I bet the 400 speed test results will be "better" .....

 

[c6h6o3]

Shoot your test on rollfilm and just go 2 stops over and 2 stops under on the same roll of the same scene. Then develop according to the manufacturer's instructions. Then, and this is the most important thing, print all the negatives. Make the best print you can from each negative. You won't believe how much you'll learn from doing this, and not just about your personal film speed.

 

[wiggywag]

I have also read what Bruce says and I feel you are missing some important steps in his method. He says: After finding the exposure just about base fog then cut the ISO in half, then remember to put shadows in zone 4. That will give well exposed negatives

 

[gphoto120]

Thanks for the suggestions! I'm going to shoot another roll and evaluate per the advice given.

 

[c6h6o3]

I have also read what Bruce says and I feel you are missing some important steps in his method. He says: After finding the exposure just about base fog then cut the ISO in half, then remember to put shadows in zone 4. That will give well exposed negatives

It was Barnbaum's influence which inspired me to take photography seiously and work toward becoming an artist. It's been quite a few years since I took his workshop, but I believe my criticism is still valid. Zone I will always be on the non-linear portion of the curve. Not only does it not give you any information about the straight line portion of the curve, which is what we need, but since the response function is non-linear down there one more stop in exposure will not result in one stop's worth of additional Zone I density. However, once you've found the minimum speed where one more stop of exposure turns Zone III into Zone IV, you've got it. I've always found it ironic that Bruce would espouse the Adams method since he's a mathematician.

BTW, I rate my TMY at 200 and place the darkest part of the picture on Zone IV. Kinda sounds like what he recommends, doesn't it? I've never measured either base fog or Zone I on my negatives and couldn't care less where either of them lies.

 

[schlger]

Your user name leeds m to the conclusiont that you use Pyro developer. In my experience, that developer produces low densities in Zone 1 to 3 but a high contrast in that region, so one can utilize that compared to usual Zone System advices very low densities and yield shadows with sufficent separation.

 

[c6h6o3]

Your user name leeds m to the conclusiont that you use Pyro developer. In my experience, that developer produces low densities in Zone 1 to 3 but a high contrast in that region, so one can utilize that compared to usual Zone System advices very low densities and yield shadows with sufficent separation.

Sometimes I use Pyrocat HD, but not very often; only for semi-stand development. 90% of the time I use Harvey's 777. It behaves very differently than any catechol or pyrogallol based staining developer.

 

[jgjbowen]

Sometimes I use Pyrocat HD, but not very often; only for semi-stand development. 90% of the time I use Harvey's 777. It behaves very differently than any catechol or pyrogallol based staining developer.

Jim,

Do you mix your Harvey's from scratch or purchase it from the group from Louisville listed in the article?

Thanks,

 

[c6h6o3]

Jim,

Do you mix your Harvey's from scratch or purchase it from the group from Louisville listed in the article?

Thanks,

I buy it from BPI. I can't mix it from scratch as I don't know the formula. As D.F. Cardwell points out in his addendum to Fred DeVan's article on Unblinkingeye, Germain's (for which we do know the formula) is not 777 (the formula for which BIP simply will not divulge).

 

[jgjbowen]

Thanks Jim

 

[Doremus Scudder]

A couple of thoughts on Bruce Barnbaum's methodology.

First, placing shadows on Zone IV and the highlights on Zone VIII, which is, I believe, what Barnbaum recommends, compresses the density range on the negative one Zone from Ansel Adams' recommendations. In other words, there is a one-zone smaller density range from important shadow to important highlight than the "original" Zone System.

This is similar to, but not quite the same as, an N-1 development scheme. The difference is that the shadows are placed higher on the film's characteristic curve since the speed point is determined in much the same way. Zone VIII densities will be the same for both systems, but the shadows placed on Zone IV will be much more luminous and detailed and, given that they are up off the toe of the film's curve, will have more separation. It's the mid-tones that will end up having slightly less separation in Barnbaum's method.

In practice, there is usually a lot of darker values in the metered shadow areas, which are rendered darker than Zone IV and give the print an anchor in the lower values. A print with Zone VI as the lowest density will look washed out.

The key word here is "important" shadows.

A similar method of getting the shadows up on to the straight-line portion of the curve is simply to give more exposure, effectively "overexposing" the negative (a typical trick of Tri-X users, since this film has such a long toe). This can retain the separation of 5 Zones between Zone III and Zone VIII (while Barnbaum's method yields only 4 Zones difference).

Films with long straight-line portions and short toes require less of this moving the shadow values up the curve to achieve the same separation.

The question of which system to use is really one of visualization. Many find the less-contrasty approach of Barnbaum to yield richer prints. Many who use the "classic" shadow placement of Zone III get much the same result by indicating N-1 developments for situations that Barnbaum might consider "Normal."

In the end, it is really about knowing what you are going to get when you trip the shutter.

FWIW, I place important shadows on both Zones III and IV depending on how much detail I want in them and how "luminous" or "snappy" I want the final print to be. And, since I use Tri-X a lot, I "overexpose" it to get the shadows up on the curve. This results in denser negatives than some have, I suppose, but they print just fine. I think I remember someone commenting, after seeing Bruce Barnbaum's negatives, that they were "bulletproof."

Best,

Doremus Scudder
www.DoremusScudder.com

 

[c6h6o3]

I basically expose the same way that Barnbaum does. I like a scale in my negatives which is compressed "from the bottom up", so to speak. That gives a presence and glow to the middle grays I can't get with any other method. I just don't see how placement of Zone I has anything to do with determining useful film speed.

I also find that most of my negatives do not print well on a grade 2 paper. I usually have to use grade 3 with a water bath. If I back off a little on exposure, dropping the shadows back into Zone III and develop a little more to get Zone VIII highlights, the negative will print easily on a grade 2 paper but the shadows will be inky black with no detail. Sometimes this works aesthetically, usually not.

One of the reasons I like Harvey's so much is the fact that as Fred DeVan says: "You can develop until the negs look like soot and as long as the agitation is not too much and retain an easily printable result with bright open shadow detail. The highlights do not pack up as you would expect." Some of mine look bulletproof, but print easily with good highlights.