Mass dev chart and tmax 100 old and new

[ibcrewin]

I have two rolls of Tmax 100 I'm exposing at EI400. Was going to use d76 1+1 for a 2 stop push. But, while I was looking around the mass dev (thinking about using hc-110 dil b), I noticed something odd. This is from the mass dev chart:
TMax 100 HC-110 B 100-200 6min
TMax 100 HC-110 B 100-200 7min [notes]
TMax 100 HC-110 B 400 11.5min
TMax 100 HC-110 B 400 9.5min [notes]

so normal processing old tmax takes 7min, 1 min LONGER than the new version. BUT, when pushing it to 400. The old tmax is processed for 2 minutes LESS than the new. What's up with that?

 

[venchka]

Nope. Those numbers come from users. Go to Kodak. Find the Tmax100 pdf. Use those numbers as a starting point. Kodak has always claimed a 1 stop increase in film speed at the same development time. How that works only the Gnomes of Rochester know for sure.
If you want 400 speed film, use 400 speed film. New Tmax 400 exposed & developed normally will look like Tmax 100. Which is to say a lot better than Tmax 100 @ 400.
Why does everybody want to reinvent the wheel all the time?

 

[charjohncarter]

I use Tmax 100 all the time. And I use HC-110h. You just have to try A TIME and then adjust. But really the ballpark figure will give a good starting point. So as from your post try 10.5 minutes for the 400 push or 6.5 for the 100-200 EI(ISO).

By the way when you finally get a good time you will be very happy. Kodak is 'down wrapped' (to quote my old secretary), but they (and Ilford) make a very consistent product so once you get a time it will be good. And the old stuff is so old you should not be concerned.

Also, for my digitalization process I do the equivalent of 8 minutes for 100 EI(ISO).

 

[ibcrewin]

Great! Thanks for the input!

 

[venchka]

You didn't answer the question.

 

[ibcrewin]

In my case I have a lot of 100iso wheels that I got for free, but no 400iso wheels. So I want to putting fancy hub caps on my 100iso wheels to make it look like 400 iso wheels.

Btw, generally i'm a shoot at box speed type of guy.

 

[venchka]

Try spliting the difference and sticking to what Kodak says is possible with Tmax film. 200 should do just fine. In fact, according to Kodak, the box speed is 100 & 200. Tmax 400 is 400 & 800.

 

[ibcrewin]

I'll give that a shot if 400 fails miserably.