Re: Push & N+1 processing


Steven Woody wrote:
> "UC" <uraniumcommittee@xxxxxxxxx> writes:
>
> > Steve:
> >
> > Here is what you need to know:
> >
> > Sped is measured at a standard degree of development. This standard
> > uses a 'speed point' which is a point on the H&D curve at which the
> > curve achieves a defined slope. The particular slope is chosen because
> > a minimum CONTRAST is necessary to achieve detail. That slope-point is
> > used for all films. You need such a point to be so defined to be able
> > to measure film speed, because the point moves a little with changes in
> > the degree of development. So, all films are developed the same degree
> > for speed testing. Is that clear?
>
> i so much interested in how to determind the slope-point( or speed point) in a
> given curve. could you teach me?

Juist look at the ISO standard. You have to buy it.

http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=3580&ICS1=37&ICS2=40&ICS3=20

> > Changing the degree of development makes very little actual difference
> > in the usable speed (maybe 1/3 stop, despite what you may have heard.
> > As development time is increased, contrast increases, and if
> > development is prolonged by 100%, contrast becomes very much higher
> > than normal. Grain also rapidly increases.
>
>
> > Just forget about pushing and N+1. It will not increase your speed at
> > all.
>
> i believe what you said. i just want to by discussing to know more arround the point.

What is there to discuss?

Speed is measured at a certain point on the curve, when the slope
reaches a specified percentage of the straight-line slope.

.

Relevant Pages

  • Re: Push & N+1 processing
    ... > Sped is measured at a standard degree of development. ... > curve achieves a defined slope. ... > a minimum CONTRAST is necessary to achieve detail. ... all films are developed the same degree ...
    (rec.photo.darkroom)
  • Re: Differences in Aptitude
    ... the red curve means that the group of particular math capacity, ... Gauss curve, or some kind of probability distribution ... standard way of presenting experimental data. ... airhead. ...
    (soc.men)
  • Re: Hey, Jobst, on p39 of The Bicycle Wheel the graph appears to show the ?impossibility of...
    ... force' curve. ... not leftwards and rightwards force. ... out a magnifier and start counting pixels to see that the slope of the ... is going slack around 0mm deflection; ...
    (rec.bicycles.tech)
  • Re: what "REALLY" is derivative?
    ... then it's easy to solve for the slope of the line (because ... excuse to divide f- fby x - a. ... but have you tried finding derivatives of functions ... curve on a piece of paper and call your curve f. ...
    (sci.math)
  • Gorilla Testing: Re: Differences in Aptitude
    ... the red curve means that the group of particular math capacity, ... Gauss curve, or some kind of probability distribution ... standard way of presenting experimental data. ...
    (soc.men)