HP5+ vs Tri-X when pushing

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Steven Woody - 22 Jul 2006 13:32 GMT

hi,

i want to know which one is better when pushing? and which one is
faster ( in real ASA )?

p.s. suppoes D-76 devloper will be used.

thanks.

-
woody

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ellis@no.spam - 22 Jul 2006 17:50 GMT

>i want to know which one is better when pushing? and which one is
>faster ( in real ASA )?

The real "ASA" is the one printed on the box. Pushing only increases
the slope of the curve, i.e. it ups the contrast.

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Steven Woody - 23 Jul 2006 02:36 GMT

> >i want to know which one is better when pushing? and which one is
> >faster ( in real ASA )?
>
> The real "ASA" is the one printed on the box. Pushing only increases
> the slope of the curve, i.e. it ups the contrast.

by real 'asa', i mean the film speed acording to human experience when
use a film in practice.

pushing increases the overall contrast by means of move most lower
value zones to high value zones, hence increases brightness. that's
kinda of human feeling of 'speed'.

please answer the queston directly. thanks.

-
woody

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ellis@no.spam - 28 Jul 2006 21:50 GMT

>by real 'asa', i mean the film speed acording to human experience when
>use a film in practice.

That would be EI. ASA (now ISO) has a strict definition.

>pushing increases the overall contrast by means of move most lower
>value zones to high value zones, hence increases brightness.

The lower zones don't change much at all with longer processing (other
than increasing fog base). All you do it increase contrast.

>that's kinda of human feeling of 'speed'.

No, it isn't.

>please answer the queston directly. thanks.

Please do some tests and answer it for yourself.

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jon fabian - 24 Jul 2006 08:20 GMT

> i want to know which one is better when pushing? and which one is
> faster ( in real ASA )?
>
> p.s. suppoes D-76 devloper will be used.

The two emulsions are different; neither is "better". HP5 is more
contrasty than TriX out of the box so it will push contrastier. TriX's
grain structure hasn't changed much over the decades so the larger grain
shouldn't seem as intrusive as HP5's. Since HP5 has more of a "T" style
grain, when pushed it resembles (IMHO) high-speed color neg grain.

If you are after contrast HC-110 or equivalent might be a better choice
than D-76. D-76 is pretty neutral and very kind to midtones. But
processing method also plays a role. D-76 in a small tank will yield
different results than dip-n-dunk with nitrogen burst agitation.

Speed, like contrast and grain is relative and subjective. Some people
regularly pull 400 to 200 for a wider latitude. Some people push 400 to
800 or 1600 for available light or monster grain.

Remember the first rule of photography: "Light interacts with silver
salts; all else is negotiable."

Hope this helps,

Jon

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Steven Woody - 24 Jul 2006 09:25 GMT

> > i want to know which one is better when pushing? and which one is
> > faster ( in real ASA )?
[quoted text clipped - 22 lines]
>
> Jon

thank you for your advices, Joh.

-
woody

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