Tetenal Ultrafin instruction - what is Beta 0,55?

there there development time - as I can understand, for agitation once per 3 sec, and once per minute.
but what does it mean Beta 0,55 and Beta 0,70?
dev.time differs up to x1,8

I'm looking for a dev.time for Tri-X 400 in Ultrafin liquid, this table gives me different time,
from 9min to 16 min (1:10, different source). where is the truth?

taken from here:
http://www.blende7.at/datenblaetter/tetenal/entwicklungszeit-SW_tetenal.pdf

The developer times are being given for two different contrast indexes, this was more common a few years ago, but Ilford & Kodak seem to have dropped it in many of their data sheets. Ilford refer to the contrast as the G - Gamma and this indicates how the slope of the curve changes with increased development, Kodak use CI, Contrast index. These both refer to the contrast of negatives required for printing with different types of enlarger.

The Tetenal Beta 0,55 or 0,70 is similar, usually the lower figure is for Condenser enlargers, and the higher for diffuser enlargers. Most enlargers with a colour or multigrade head fall somewhere in between. My gut feeling is to give 12mins @ 20°C normal inversion processing if you're using a colour head, and in fact Dead Link Removed and it recommends the same

The Jobo page is far more helpful than Tetenal's data-sheet, essentially it's recommending the same but gives more useful detailed information.

Ian

Why to stick to enlarger type and not just regulate contrast by using appropriate multigrade filters?
My enlarger is condenser type with interchangeable filters (as most of them are). But I can occasionally print in professional lab, where is Durst (diffusion type).
If I'm going to print on multigrade paper, can I select some intermediate values? (let's say 10,5 min instead of 9/12 for different Betas)

Not everyone uses Multigrade type papers, so it can be important. Most condenser enlargers are quite diffuse, they use coated bulbs. Certainly my Durst M601 was very similar in contrast regardless of whether I used the condensers or the colour head.

So you'd be better to start with the 12 minute development time. You can always drp the time slightly if necessary the next time.

Ian

hi what is beta? please tell me soon i cant lealized beta ( help me please tell the complete explanation

Hallo Azin, here is a link to a page with some good explanations of the terms used in talking about contrast and development and clear examples of what they mean in practice. That site also has a lot more information too. The writer is also an APUG member.

You can probably best look around the Ilford-Photo and Kodak websites for extremely detailed technical information if you feel that you need more detail. Good luck !!

I believe it is Tetenal's equivalent of G-bar which preceded (I think?) contrast index.

Beta 0.55 is for condenser enlargers and Beta 0.70 is for cold cathode light source enlargers. Most people average the two times and adjust to the require contrast from there any way which is most likely why Kodak and Ilford only give a single time to start with.

Scanners don't like contrasty negs.

Wet printing on normal grade is easier to get a nice print, it was annoying to have to stock a range of grades. before variable contrast.

All these measures of contrast (Gamma, Beta, CI, etc) are determined from the Characteristic Curve (Hurter & Driffield curve) and are very similar. They vary only slightly in the way they are calculated.