Rookie question...

[jackbond]

Okay, so I just recently (as in the last two weeks) starting using medium format film, and I absolutely love it. It is incredible. Today I made a very rookie mistake, however, and thus have a very rookie question for you all.
I finished a roll of 400 B&W today, and as I was removing the cartridge I realized I had the camera set to ISO100, the speed of the previous roll. What should I tell the developer to get photos with the correct exposure? If i have learned correctly, I should tell them to pull two stops, and I will have developed photos at the correct exposure, just with probably lower contrast than if they were shot correctly, right?
Thanks for any replies!

 

[MattKing]

Welcome to APUG.

You aren't the first to do this, and you won't be the last.

What film were you using, and what was the light like (low contrast, high overhead cloud; sunny day with dark shadows; near sunset with directional light; wedding reception exposed with on camera flash; or?

 

[jackbond]

Most of the photos were daytime street portraits: IE mostly natural, sunny light, but i avoided high contrast shadows in general. Its been snowy where i live so the lights been pretty diffused. I was using a meter so they should be properly exposed had i not made the ISO mistake.

I was using a roll of Kodak 400 Tmax B&W.

 

[David Lyga]

You just might get BETTER photos; that is, if your processor does not overdevelop the film. Actually, '400' film CAN be exposed as '100' if you are careful not to overdevelop. There is LOTS of latitude in your film, yes, even if it was the 'unforgiving' TMAX 400. The negatives will be dense, but fully separated, tonally. - David Lyga

 

[jackbond]

Interesting, I was underexposing by about half a stop in general for a more low-light look, but i think most of the pictures would also look fine a little bright and dreamy, do you think if i tell the developer to pull the pictures one stop that that would be a good compromise? at worst, they would be a little underexposed or overexposed, but most of the pictures i think would work stylistically either way.

 

[MattKing]

Most of the photos were daytime street portraits: IE mostly natural, sunny light, but i avoided high contrast shadows in general. Its been snowy where i live so the lights been pretty diffused. I was using a meter so they should be properly exposed had i not made the ISO mistake.

I was using a roll of Kodak 400 Tmax B&W.

In diffused light, I would develop normally or, at most, pull by one stop.

TMax 400 has good over-exposure latitude. Many people prefer to meter with it as low as EI 200. If you pull develop, you affect contrast more than exposure.

If you have a good relationship with your lab, you should ask them as well.

Or take up developing the film yourself. It is easy, and very rewarding.

If the photos are particularly important, you could shoot another roll in the same conditions and then see how that test roll comes out before deciding on changing from standard development.

 

[Arklatexian]

Okay, so I just recently (as in the last two weeks) starting using medium format film, and I absolutely love it. It is incredible. Today I made a very rookie mistake, however, and thus have a very rookie question for you all.
I finished a roll of 400 B&W today, and as I was removing the cartridge I realized I had the camera set to ISO100, the speed of the previous roll. What should I tell the developer to get photos with the correct exposure? If i have learned correctly, I should tell them to pull two stops, and I will have developed photos at the correct exposure, just with probably lower contrast than if they were shot correctly, right?
Thanks for any replies!

I don't know if this will help. At one time I did custom photofinishing for a camera store. A customer left a roll of 120 Tri-X on a Friday. Over the weekend, I processed the film normally (for ASA 400). Monday morning, the customer called the store telling them he had shot the film at ASA 100 and could I develop for that. As the film was already developed and prints made, it was too late. The negatives printed beautifully and I had not noticed any problems. Maybe the customer and I both were lucky or it did not make that much difference. I do like the idea of doing a sacrificial roll of unimportant subjects and see what happens as has been suggested.....Regards

 

[cliveh]

and as I was removing the cartridge

May I ask what you mean by this? Do you mean a roll of 120 film?

 

[jackbond]

Yes sorry, I was just removing the exposed roll from the back.

 

[Xmas]

don't worry try to be more disciplined in future.
two stops with tmax no problem some people need to rate at 200-250 anyway
ignored concepts like push and pull they are like fairy tales
http://www.ilfordphoto.com/aboutus/page.asp?n=31

 

[mgb74]

What type of meter were you using and how did you meter? I ask because if your scene included snow, and you did not spot meter or adjust for that, you may be significantly underexposed at iso 400.

So it's possible that by metering at iso 100, you metered correctly.

 

[M Carter]

ignored concepts like push and pull they are like fairy tales
http://www.ilfordphoto.com/aboutus/page.asp?n=31

Should the OP get into shooting E6.... disregard the above push pull comment!

 

[Sirius Glass]

Welcome to APUG