Personal EI for 100 and 400 Tmax films

[john_cullen1]

Several months ago I started testing my cameras to determine my

personal EI and normal development time for 100 and 400 Tmax. I

followed the instructions carefully when making my exposures and ran

several tests to determine the appropriate "normal" development time

for each film. The results were unexpected - everyone seems to

suggest that the personal EI will, in most cases, be significantly

lower than the manufacturer's suggested EI. In my case, they were

always higher - i.e. I had to increase the exposure to produce a

correct zone 2 and zone 8 negative.

 

In my case, I tested the following cameras/lenses and received the

same results for each. Hasselblad 50mm, 110mm, 150mm, 38mm; Mamiya

RZ67 90mm; Rodenstock 210 (4x5); Mamiya 7 - 65m lens.

 

I shot my test film at the suggested ISO and at two ISO's below and

one above the manufacture�s suggested ISO. For 400 Tmax, I used 400,

320, 200, and 500. For each ISO, is used a gray card and adjusted

the F-stop to record a zone 1(closed down 4 stops) and a zone 8

exposure (opened three stops).

 

My result, in each case, is 500 EI for 400 Tmax and 160 EI for 100

Tmax.

 

All films were developed in Xtol, 1:1, for 5.5 - 6 minutes with

continuous agitation for the first 30 seconds and then four

inversions every 30 seconds. The development time was determined

after several test rolls used to determine my personal development

time with these two films and developer combination.

 

I guess what I am asking is this - has anyone else had similar

results with these two films? My negatives seem to be quite good and

easy to print but what bothers me is the nagging feeling that I have

performed the test incorrectly and that my negatives really could be

better. Any advise/help/experience would be most welcome. Thanks.

[ed_skibeki]

"The results were unexpected - everyone seems to suggest that the personal EI will, in most cases, be significantly lower than the manufacturer's suggested EI. In my case, they were always higher - i.e. I had to increase the exposure to produce a correct zone 2 and zone 8 negative."

 

Unless you meant something different, "increasing exposure", for example 1/2 second instead of 1/4 second, is entirely consistent with rating the film at a lower speed.

[roger krueger]

I'm not surprised at all that XTOL 1:1 gave a little extra speed, that's its nature.

 

And if you've got negatives you like that are easy to print why are you obsessing on this? The Zone system is a method to predictably get to this point, not an end in itself. If it in fact has gotten you here, you've done it right.

[john_cullen1]

Hi Ernie and thanks for the reply.

 

I guess what I meant to say, and should have said, was that I could not get a correct zone 2 negative unless I rated the film at 500 ISO. All the other speeds did not produce the near black negative when exposed for Dmax. That is the procedure I followed to determine my personal EI. The zone 8 negative was used to determine correct development time.

 

Hope that makes things clearer. Any advice?

 

Thanks again.

[john_cullen1]

Hi Roger and thanks for your reply. I guess I am obsessing because I am never really satisfied with my end results. They are "satisfactory" to me but I never expected all of my equipment to produce the same result. If I had several lenses that produced different results, I probably would not obsess as much but the fact that they all came in about the same tends to make the hair on my neck stand on end.

 

I am hopeful that someone else will have had a similar experience with the Tmax films.

 

Thanks again.

[ed_skibeki]

My first instinct would be to examine how you are determining "zone 2" values. Via densitometer readings of the negative or by evaluating print values?

 

If the latter, I think there is a lot of subjectivity involved in making this assessment. Have you determined what exposure under the enlarger is required to establish maximum black for a grade 2 or equivalent multi contrast paper?

 

Second I would look at the exposure meter. They're notoriously variable & may create the result you've experienced. Not a problem, as long as they remain consistent.

[hans_beckert]

John:

 

How are you printing? What kind of enlarger and lens? What paper? If you do not take printing into account, it is rather difficult to establish speeds. I suggest you try to make a 'typical' scene print properly on approximately grade 2 1/2 Ilford Multigrade.

 

My testings of these films shows lower speed for T-Max 400 than you get (i.e., 250-320), but about 125 for T-Max 100.

[ian_beales1]

John,

 

It appears from one of your followup responses that you are aiming for an exposure or development time that results in Dmax for the film. Exposing at Zone 1 will give you the speed point of the film (i.e. the "correct" speed will result in a density of 0.10 + film base + fog at Zone 1 exposure). Adjusting the developing time will give the "correct" Zone 8 density. Adjusting the dilution will allow you to tailor the densities of the intermediate zones somewhat.

 

Determining your personal EI is something that apparently too few people do. I'd aim for establishing personal EI, then correct development. Then if you are really picky establish the dilution to suit your needs. The first 2 are well worth it, the 3rd not so much.

[hans_beckert]

Ian:

 

All three are interrelated: Time, speed, and dilution.

[bruce watson]

John,

 

XTOL tends to give you more real film speed. It isn't surprising that you are seeing the EIs you are. If you are getting negatives that are easy to print on #2 papers, take the extra speed and run.

 

I'm using 4x5 Tri-X and XTOL 1:3. I've backed off development to get thinner negatives for scanning, and it still gives me an EI of 320.

 

What you are seeing is perfectly normal.

[al_kaplan1]

If it ain't broke don't fix it. Now got out and shoot some pictures.

[m0002a]

I am sorry but my personal EI's are personal and confidential. If I told you, I would have to shoot you.

[lex_jenkins]

Doesn't surprise me that you found TMY to be faster than the rated speed. In my use with the stuff it responds readily to a speed enhancing developer like Microphen. (I routinely push TMY to 1600 in Microphen, tho' I'm definitely not claiming this is anywhere near its true speed.)

 

I'm not an Xtol user (tried it once, tho') but many folks report it is a speed enhancing developer. And the agitation technique you described may further enhance the speed. Have you tested with longer intervals between agitations?

 

I haven't found that any of my favorite developers will wring more than EI 100, tops, out of TMX, tho'.

[roger_hicks1]

Dear John,

 

Don't worry about it. My personal EIs vary from 2/3 stop under (HP5 in Perceptol) to 2/3 stop over (HP5 in DDX). These actually correspond very closely to the true ISO speed in those developers. With spot meter readings of the shadows -- the only theoretically correct way to determine exposure for negative materials, though other readings can be made to work well enough -- I can use the full ISO speed and an IRE 1 index.

 

In order to get negs that print well on grade 2 with my system (Meograde on Magnifax 4, Multigrade Warmtone, Multigrade developer), I normally develop for longer than the manufacturers' recommended times, corresponding to the times for a G-bar of 0.70 or thereabouts. Again, a lot of people say this is 'wrong' -- you should always develop for less time than the manufacturers' recommendations. This is of course twaddle. You should develop for the times that work for you.

 

I don't know how many cameras and lenses I own but most of the newer lenses and cameras do in fact deliver very, very similar results. There's one lens (35/5.6 Apo-Grandagon on an Alpa, normally used with 6x9cm) where I have to give a stop extra, and with some of my older cameras I can cut a stop because the shutters are slow. With the 90/4 Dreamagon I normally cut one stop because of flare; I recently cut 1/2 stop with a Thambar I borrowed, for the same reason.

 

The truth, though, is that none of it matters very much. I am relatively seldom disappointed in a picture for technical reasons: much more often, I am disappointed because of composition or content or (in the studio) lighting. As long as you don't under-expose (at which point quality falls off a cliff) it's not hard to get a good negative with most of the films I use, especially Ilford HP5 and XP2, Paterson Acupan 200 (at 125 or 160 -- it's only 200, and barely that, in speed-increasing developers), Kodak Tri-X and Maco Cube 400.

 

Cheers,

 

Roger

[chris_waller]

With any new film (new to me, that is) I use the Zone System method for determining PEI as laid down by Adams. I used to use a condenser enlarger but have just recently bought a Meopta Magnifax 4a with Meograde head. This latter is a diffuser head and thus I am in the process of redetermining my development times. Typically I find my PEIs to be about 1 to 1 2/3 stops below the manufacturer's stated speed. This comes as no surprise with a condenser head. With the diffuser head I could possibly raise my PEI but I have decided simply to increase development times.

[chris_waller]

Sorry! That should have read, "1 to 1 1/3 stops ...".

[rick_jones5]

If your "negatives seem to be quite good and easy to print" don't start second guessing yourself. In fact, I wouldn't be the least bit concerned what others where doing.