Same film different size

[tkamiya]

I have been experimenting with Tmax 400 in 135 and 120 sizes. My initial perception was, since these are the same film, they behave identically. However, my short experience is showing me otherwise.

For example...

Tmax400 in 135 developed with XTOL 1:1 at specified time per chart almost always ends up being a little too contrasty in my process. -10% time seems to do it just right for me.

Tmax400 in 120 developed with XTOL 1:1 at specified time per chart seems to be just right.

Looking at negatives, similar exposure looks a lot darker in 135 than 120.

Looking at prints, ones from 120 looks creamier and smoother than 135. (both enlarged to 8x10) but not as much as enlargement factor might otherwise suggest.

Now, the question part....

Are these difference coming from shutter/departure calibration issues in camera? My processing is very consistent with use of water bath, temp, and timing, including agitation.

Or... are these difference coming from different enlargement factor? Obviously, 135 enlarged to 8x10 has been magnified to far greater degree than 120 to 8x10.

Or... are they really not the same film, or shouldn't be treated as such?

These tests weren't scientific. I didn't have two cameras set on tripod side-by-side. But with number of films on both, these tendencies seems to be very consistent.

I'm trying to hone in my calibration and I could use some help.

 

[fschifano]

Some of the difference you are seeing are could be coming from differences between the two cameras. Shutters and apertures not often equal between cameras - especially if the shutters and apertures are mechanically controlled and not electronically controlled. Even more so if one camera has a leaf shutter and the other a focal plane shutter.

Degree of magnification has a lot more to do with the look of prints from both formats. Prints made from negatives subjected to a lesser degree of enlargement will always look smoother.

The support used for TMax 400 in 120, and indeed for many other films, is different from the support used for 135 format, and that's a big reason why the negatives look different. If you subtract base density and fog from the two formats, the contrast curves should be the same for both if all other things are equal. Check the tech pub for the film here. Kodak does not publish different contrast curves for 135 and 120 versions of the film.

 

[MattKing]

What Frank says, plus:

1) the camera lenses can make a difference because of differences in contrast and coating;
2) the enlarger lenses and any difference in enlarger light paths may also make a difference; and
3) the way you agitate can lead to slightly different results, due to the different geometry of the reels with film in it.

Matt

 

[Stregone]

There also differences between the meters to think about.

 

[wogster]

There also differences between the meters to think about.

Not to mention that they are very likely different emulsion batches, so there can be slight variation batch to batch, even though Kodak (and Ilford too) are very precise about the quantity and quality of ingredients, there is still variations.

 

[fschifano]

It's true that there are variations between batches, but the major players (Kodak, Ilford, Fuji) are really picky about quality control and do their absolute best to keep that variation down to an absolute practical minimum. I doubt that the batch to batch variations can even be noticed by the user when you factor in all the other variables.

 

[df cardwell]

I have been experimenting with Tmax 400 in 135 and 120 sizes. My initial perception was, since these are the same film, they behave identically. However, my short experience is showing me otherwise.

Confirming Matt and Frank's observations.

I had 15 years of experience before TMY came out, and have used it for nearly all my work for 25 years, in 35 mm, 120, 4x5, and 8x10. The standard deviation is VERY small for the TMY evolution over the years.

In any specific set of variables, for instance shooting in low light with Camera A, using Lens B, and Developer C, it has been easy to see the influence of the scene and the influence of my emotion upon the image.

The only hope for an Intuitive photographer like myself is to nail down the variables, like film type, then weld them in place. Every lens you own, every different camera, every film and developer, multiplies the difficulty of making consistently satisfying pictures.

TMY's consistency makes photography MUCH easier.