README

Interfaces, classes and decorators for the speed point of a film developing.

Installation

$ composer require filmtools/speedpoint

Interfaces and Classes

SpeedPointInterface

use FilmTools\SpeedPoint\SpeedPointInterface;  

getType() : string|null Returns name or description (film speed evaluation method).

getValue() : float|null Returns the speed point exposure value which yields a certain minimum density.

getSpeedLoss() : float|null Returns the difference between the real speed point and the exposure value where the minimum density had been expected.

getEICorrection() : float|null Converts the "speed loss" to Exposure Index (°DIN) steps. The correction value is negative when the film needs “more light”.

valid() : bool Returns true if the value is valid.

SpeedPointProviderInterface

use FilmTools\SpeedPoint\SpeedPointProviderInterface; 

getSpeedPoint() : SpeedPointInterface Returns a Speed point instance.

SpeedPoint

The ready-to-use SpeedPoint class extends SpeedPointAbstract and implements the SpeedPointInterface.

use FilmTools\SpeedPoint\SpeedPoint;

// The exposure value where a density is reached
$logH = 0.46;

// Text description is optional. 
$sp = new SpeedPoint( $logH );
$sp = new SpeedPoint( $logH, "Description" );

// Examples:
$sp->getValue();        // 0.46
$sp->getSpeedLoss();    // 0.16
$sp->getEICorrection(); // -3.0
$sp->getType();         // "Description", may be null.

Development and Testing

$ git clone https://github.com/filmtools/speedpoint.git
$ cd speedpoint
$ composer install

$ composer test