Rating of TMAX 400 and 100

[John MacKechnie]

I'll be doing some Zone System testing to determine the best combination for my equipment and processing, but naturally I'm anxious to get out there and expose of couple of negatives.

Are ratings of 200 for the TMAX 400 and 50 for the TMAX 100 a good starting point.

Thanks, John

[steve simmons]

Maybe, but it depends. Why not spend a day and do the testng for both EI and development time. It is time well spent.

steve simmons

[Ron Marshall]

With TMX in XTOL 1:2 I get an EI of 80. With TMY in XTOL 1:2 I get an EI of 320. Most other developers will be a bit less, so 50/200 is a reasonable starting point, but much depends of course on what developer you are using.

But as Steve said, it is better to test.

[Louie Powell]

I've tested TMY in HC110 several times with results ranging from EI 180 to about EI 240.

[Michael Kadillak]

I'll be doing some Zone System testing to determine the best combination for my equipment and processing, but naturally I'm anxious to get out there and expose of couple of negatives.

Are ratings of 200 for the TMAX 400 and 50 for the TMAX 100 a good starting point.

Thanks, John

It depends upon the developer (in other words the shape of the film curve generated from the combination). I find T Max 100 needs very stringent temprature and agitation control as found with the JOBO rotary processing system as employed by John Sexton. T Max 400 is at the opposite end of the spectrum with these variables and is very compatable with tray development and other manual processing techniques.

T Max 400 in pyrocat exhibits a very straight line H&D curve from toe to heel and you could use an ASA of 320 as a starting point. In pyro with the long toe an ASA of 200 or even lower would be advised.

As Steve said, the time you would spend testing for yourself would be the best advice.

Cheers!

[Matt Miller]

I've always shot TMY at 400 and tray develop in Pyrocat HD.

[Michael Heald]

I use TMax RS 1:7, and for TMax 400 with a uniroller drum continuous agitation, my EI is 500 with several testings through View Camera Store. Best regards.

Michael A. Heald

[Photobackpacker]

The EI results you get are unique to your light meter, water characteristics, developer, thermometer, processing temperature control, processing agitation style, method and speed, time control and so on. Essentially, by following Steve's suggestion, you will give yourself a chance to standardize these factors working with sheets that do not represent your potential masterpiece. Make sure you use enough developer so you do not exhaust it when processing your pictures of Snow Geese standing on snow. ;)

I have a suggestion for saving film and time that I use. I went to an office supply store and purchased some black binder covers - the flexible plastic variety that are approximately the same thickness as a darkslide. I cut these to the size of a darkslide, drilled 3/8" holes spaced so each exposure will have 3/4" edge separation from the next. Using these, I can get 12 exposures on 1 sheet of film.

Slides 1 thru 4 are numbered 9 through 12 (respectively) on the reverse side as they are reversed to make the exposure on either side of the center exposures.

This binder cover material is not dense enough to use as a dark-slide but is dense enough to prevent fogging when used with the filmholder in the camera.

By recording the data on the sheet of film, you will have a record that is a diary of your work. I plot my results in an Excel spreadsheet.

I cannot take credit for this system but I cannot remember where the idea came from to give credit to the originator.

To simplfy achieving absolutely even lighting over the course of 12 exposures, I slapped together a home made ring light. This mounts on a light stand or tripod and allows you to set your camera up behind the ring light and shoot through the center of the light source. I use the blue-tinted lights to approximate daylight color temp. With a spotmeter, you can meter nearly anywhere in the middle of the sheet of mat board you are using as a target and get the same reading as when metering through the center hole of the "ringlight". This means you don't need to move the camera once it is set.

Good Luck!!

[Ken Lee]

According to Ctein at http://theonlinephotographer.typepad.com/the_online_photographer/2007/10/index.html,

"In 1955 Tri-X had an ASA (ISO's predecessor) of 200. In 1965 it was 400. The film hadn't changed, just the official judgement of what the best exposure was. Higher exposure of B&W film produces better shadow detail, but increased grain and poorer sharpness."

In a similar vein, I suspect that TMX and TMY have always "really" been ISO 50 and 200 respectively.

From what I have observed, when most people test them, they get those speeds too, within a fraction of an f-stop. That fraction, I attribute to predictable variations in water, thermometers, agitation, etc.

[Roy L Faverty]

64 ei for tmax 100 if using HC110 or rodinal, I have tested extensively

[Jim Noel]

Bruce's idea works, except I drilled a dark slide with 8 holes which is enough.

In order to assure even lighting I set a large sheet of paper up on in the shade on the north side of the house.

The rest of my process would take too long to explain on the forum as it enables me to determine EI and development time with 3 sheets of film.