TMY/TMX film tests

[Chuck_P]

I thought I would share some film test data because I think the results are unexpected and perhaps you could give me your thoughts. I purposely did not do exposures of -1/3, -2/3, and -1 because I was sure that the speed point would be in the area of +1/3 to +1 range. My methodology is pretty standard and I'm maticulous, but I'm open to your comments. I'll certainly use the -1/3 or -2/3 speed if indeed that's how it shakes out, but I just wasn't expecting that and I wonder if maybe I've done something wrong or if the other parameters are suspect.

Preliminaries: both developed in D-76 (1+1); 68 deg F; dip-n-dunk method using three Combi-Plan tanks; water pre-soak; TMY Kodak recommended time of 12.5 min; TMX Kodak recommended time of 9.5 min.

camera: 4x5 Horseman LE, Rodenstock Sironar-N 210 MC lens, focus at infinity

Light Conditions: shaded side of my house on a cloudless day, very uniform light.

Test Target: middle gray mat board with uniform ev's using a analog Pentax 1 degree meter

TMY fb+f absolute density = .09
Zone I at box speed = .15 net
Zone I at +1/3 = .24 net
Zone I at +2/3 = .32 net
Zone I at +1 = .40 net

TMX fb+f absolute density = .04
Zone I at box speed = .19 net
Zone I +1/3 = .25 net
Zone I +2/3 = .31 net
Zone I +1 = .39 net

My densitometer is working good and calibrates properly. It certainly looks like a Zone I net density of between .09 and 0.11 is going to fall on the -1/3 to -2/3 range. Has anyone else gotten results with these films when the working speed ended up being an EI faster than the box speed?

Thanks for any helpful comments.
Chuck

 

[Tom Hoskinson]

I thought I would share some film test data because I think the results are unexpected and perhaps you could give me your thoughts. I purposely did not do exposures of -1/3, -2/3, and -1 because I was sure that the speed point would be in the area of +1/3 to +1 range. My methodology is pretty standard and I'm maticulous, but I'm open to your comments. I'll certainly use the -1/3 or -2/3 speed if indeed that's how it shakes out, but I just wasn't expecting that and I wonder if maybe I've done something wrong or if the other parameters are suspect.

Preliminaries: both developed in D-76 (1+1); 68 deg F; dip-n-dunk method using three Combi-Plan tanks; water pre-soak; TMY Kodak recommended time of 12.5 min; TMX Kodak recommended time of 9.5 min.

camera: 4x5 Horseman LE, Rodenstock Sironar-N 210 MC lens, focus at infinity

Light Conditions: shaded side of my house on a cloudless day, very uniform light.

Test Target: middle gray mat board with uniform ev's using a analog Pentax 1 degree meter

TMY fb+f absolute density = .09
Zone I at box speed = .15 net
Zone I at +1/3 = .24 net
Zone I at +2/3 = .32 net
Zone I at +1 = .40 net

TMX fb+f absolute density = .04
Zone I at box speed = .19 net
Zone I +1/3 = .25 net
Zone I +2/3 = .31 net
Zone I +1 = .39 net

My densitometer is working good and calibrates properly. It certainly looks like a Zone I net density of between .09 and 0.11 is going to fall on the -1/3 to -2/3 range. Has anyone else gotten results with these films when the working speed ended up being an EI faster than the box speed?

Thanks for any helpful comments.
Chuck

(there was a url link here which no longer exists)

Take a look at this TMY D log E curve. I rate TMY at 400 EFS (Effective Film Speed) developed in Pyrocat

 

[chriscrawfordphoto]

maybe your meter needs calibrating? You could be right though since developer definately affects speed and I have not used D76 on these films.

I use a lot of TMX and TMY and find that Tmax 400 in tmax 1+7 (my fav. dev. for TMY) is 400, while TMX is EI 50 in Rodinal 1+50 or 100 in Tmax Developer.

 

[jgjbowen]

Light Conditions: shaded side of my house on a cloudless day, very uniform light.

Test Target: middle gray mat board with uniform ev's using a analog Pentax 1 degree meter

Has anyone else gotten results with these films when the working speed ended up being an EI faster than the box speed?

Thanks for any helpful comments.
Chuck

Trying to expose a Middle Gray (Zone V) subject for Zone I probably meant you used a fast shutter speed. If your shutter is a little slow at the faster shutter speeds (or any shutter speeds) you are likely to get an EI that is faster than the manufacturer states. That's why we test for our "Personal" EI.

A more useful exposure would be to expose a black card under the same lighting conditions.

 

[Chuck_P]

A more useful exposure would be to expose a black card under the same lighting conditions.

I'm glad you made notice of this because I forgot to mention that with the TMY test, I used a dark blue mat board and with the TMX test I used a middle gray mat board. I avoided the two fastest and the two slowest shutter speeds; I used a shutter speed of 1/125.

Thanks

 

[tac]

I would first check the shutter speeds and apertures for accuracy/repeatability.

I last did densitometric testing of TMax 400 when the stuff was new (D-76 1:1 @75) and ended up with an EI of 250- but who knows how the Great Yellow Father may have tweaked it since.

See Roger Hicks recent post (under TMY revised)

 

[Tom Hoskinson]

I would first check the shutter speeds and apertures for accuracy/repeatability.

I last did densitometric testing of TMax 400 when the stuff was new (D-76 1:1 @75) and ended up with an EI of 250- but who knows how the Great Yellow Father may have tweaked it since.

See Roger Hicks recent post (under TMY revised)

Yes - you can find the Kodak announcement here:

http://www.kodak.com/global/plugins...s/bw/bwFilmQAs.pdf?id=0.2.22.14.17.14.6&lc=en

Kodak states: We have also incorporated a UV barrier into the new 35 mm and 120-format films to prevent inadvertent backside static exposure. These films may look a bit more hazy when wet, similar to T-MAX 100 Film, which uses the same technology. The haze will disappear as the film dries. The new T-MAX 400 films fix the same, so don't confuse this haze with poor fixing.

Fortunately for those of us who are sheet film users!

Note that the new sheet film does not employ any UV barrier, since large-format sizes are often contact printed onto UV-sensitive materials.

 

[donbga]

Kodak states: We have also incorporated a UV barrier into the new 35 mm and 120-format films to prevent inadvertent backside static exposure.

Too bad for those that contact print 120 and 135 with UV processes ... Wish there was some way to remove the backing.

The good news is that 120 TMAX 400 will have 100 speed grain.

 

[Chuck_P]

In case someone would find it interesting...

I finished the testing with TMY and TMX for the zone I exposure range from
-1/3 to -1 stop. And it shakes out to be:

TMY: -2/3 for EI 640 0.11

TMX: -2/3 for EI 160 0.10

I'll certainly run with these results but I've only read about others or known other personal EI's to be lower than the box speed with these films. Does anyone besides me who have tested these films in D-76 (1+1) think that those EI's are odd?

Thanks
Chuck

 

[chriscrawfordphoto]

Are you using the camera's built in meter or a handheld spotmeter? Maybe the meter's off. Try using the built in if you tested with a handheld. If you used the built in and don't have a handheld meter, try another camera. If all your cameras have built in mters that match each other, or your cameras meter matches your handheld, then maybe the camera's shutter is slow and needs CLA ?

 

[tac]

Yes, I think they're odd, but that doesn't mean that they are in any way invalid. The test is repeatability. Try another camera and see if you get the same results- if so, and you are getting negs that you like (at least in terms of densities and range), then run with it. Something in your particular film usage 'system' is giving you some 'extra speed' - too many variables to enumerate here.
Again, see if you can repeat your results with another camera, if so, good.