Tura Develop

rudi · 2004-11-10T14:17:35+00:00

Habe meinen TURA 400 auf 1600 belichtet und brauche anweisung, wie der Verlängerungsfaktor für die Entwicklung ist. Kann mir da jemand helfen?

rudi

I’ve had my TURA 400 exposed at 1600 and need some guidance on the extension factor for development. Can anyone help me with this?

MirkoBoeddecker

Rudi, I haven’t actually tested this myself, but as no one else has replied yet, here’s a rule of thumb: multiply by 1.3333 (period) per f-stop. 400 -> 800 -> 1600 = 1.3333 x 1.3333 x 1.3333 = 2.37 x (multiply by the base time for 400). Best regards, Mirko

Gast

Hi Mirko, Could it be that you’ve mentally pushed the aperture one stop too far??? Otherwise, I’m afraid I can’t offer any advice on the content, as I use different films for situations like this Best regards, Axel

Micha2

Hi Axel, I reckon Mirko rates the Tura as having a 'true' ISO 200, which means it’s already pushed by one stop at an ISO 400 exposure. Bye, Micha

Gast

I reckon Mirko's got his sums wrong ;-)

Gast

I think I'll go for 1.33 times 2, and I'd like to say thank you for your help

Gast

Hi Rudi, You’ve got your maths wrong there too: 1.33 × 1.333 – so 1.333 squared is about right – but 1.3333 multiplied by 2 is definitely too long. Best regards, Martin

MirkoBoeddecker

Hi everyone, Thanks. I’d obviously miscalculated the f-stop by one. The start time in the developer tables already includes the correction needed to bring the film up to 400 – whatever the developer may be. So 1.3333 × 1.3333 = 1.78 times. Mirko

Gast

Rudi, I haven’t actually tested this myself, but as no one else has replied yet, here’s a rule of thumb: multiply by 1.3333 (period) per f-stop. 400 -> 800 -> 1600 = 1.3333 x 1.3333 x 1.3333 = 2.37 x (multiply by the base time for 400). Regards, Mirko

Hello Mirko, While browsing through the old posts, I noticed the following: in your post dated 5 February 2003, you applied the factor 1.3333 three times for the extended development from 400 to 1600 ASA. Shouldn’t that be for 2 stops: t-dev. *1.333*1.333? Regards, Thomas