These number's seem right?

After doing many tests I have come up with .1 over FB+F with my

equipment and procedure.

 

The meter and shutters are verified good.

 

I am wondering if you've ever seen TMAX 100 give .1 over FB+F at EI

32? Thats right 1 and 2/3 stops under recommended 100 ASA.

 

Here's another number for you to ponder, FB+F is .21!?!?!?

 

The densitometer checks out against a stouffer T3110 at all steps.

My development process in D76 1:1 @ 68 for 8.5 minutes.

 

Anyone think the bulk roll film could be bad?

 

It produces nice negatives.

 

-Rick

I've never tested TMAX 100. However, most films are slower than what's printed on the box, usually by about a stop. I use the exact method you're using, since that's how I meter a scene (place the low values).

 

The fb+f sounds a little high, though. Is the film old?

Maybe a bit high, but remember when you compare that those step tablets are printed on a clear base, no dyes. Most pictorial films have significant density built into the base or the emulsion. I don't think it impossible for TMX to come out at EI32, though 50 or 64 would be more what I'd expect. Remember that it's a very short toe film, so the density will change rapidly with changes in exposure. Long toe films have little slope in the shadows, so the density changes more slowly with exposure changes. The danger is that you'll have to underdevelop it to get the highlights right, to the point where the midtones are muddy. TMX is a difficult film to make look right, but going through this process is definitely worth it.

I think your E.I. is unussual, but not surprising either. Most often I've seen this film test between 50 and 80, but recently I did a set of tests with TMX and got an E.I. of 160 (200 at N+2), so every once in a while you get really odd results. The important part is it's repeatable, and I'd double check it's repeatable with a differant batch of D76 too, just to make sure. Do your development tests, find your N time, and make a test exposure, if it works and it's repeatable, that's what you've got. Your base+fog seems a little high, but that's the same results I got with my recent tests too. I was using T-Max developer for the 160 EI, and testing with Pyrocat-HD I got an EI of 50, so if 32 is your real EI and that's too slow, you might get a faster speed with another developer.

 

Peter

Thanks! Just wanted to make sure that the values are not surprising.

 

When I get more experience, I will test with other developers. Right now, I am sticking with D76. Just so I don't confuse myself any further.

 

Best regards,

 

Rick