GB/T 6846-2008Photography -- Determination of ISO safelight conditions (English PDF)

Foreword

This standard is identical with ISO 8374:2001 "Photography --- OK ISO safelight conditions" (in English).

This standard is equivalent translation ISO 8374:2001.

For ease of use, this standard made the following editorial changes.

a) "this International Standard" be replaced by "this standard";

b) use a decimal point instead of a decimal comma ",". ",";

c) the introduction of international standards deleted, instead of the standard "foreword"; the introduction of international standards as a direct translation of this standard introduction;

d) introductory phrase Normative documents according to GB/T 1.1-2000 modified.

The revised standard and replaces GB/T 6846-1986 "safety time is determined darkroom illumination methods." Compared to this standard in content GB/T 6846-1986, the main changes are as follows.

--- The standard name according to international standard name translated from the original "safety time is determined darkroom illumination method" to "ISO photography OK "safelight conditions;

--- Increasing the foreword and introduction;

--- In order to more clearly understand the standard content of the "scope" has been clearly defined (Excerpts Chapter 1, Chapter 1, 1986);

--- Added "Normative References" chapter. ISO 8374:2001 international standard references, have been converted into the equivalent of a standard, Therefore, this standard references equivalent to international standards of national standards (Chapter 2 edition);

--- "Terms and Definitions" chapter of the expansion (Excerpts Chapter 3, Chapter 2, 1986);

--- Add "safelight conditions for maintenance and record" chapter (Chapter 4 edition);

--- Test methods are described in more detail, and adds Tier 2 (5th edition, Chapter 4 to 5, 1986);

--- Increase the "name" (first edition chapter 8) a chapter;

--- Appendix A to normative appendix, as a test method.

Appendix A of this standard is a normative appendix.

The standard proposed by China Petroleum and Chemical Industry Association.

The photosensitive material standard by the National Standardization Technical Committee (SAC/TC102) centralized.

This standard was drafted. China Lucky Film Group Corporation.

Introduction

In photography, the "safelight" is a term used to describe a light source which provides sufficient time for the user to operate it in a photosensitive no detectable change in the characteristics of the photosensitive material. Because most of the photosensitive material to be by the manufacturer or the user, or both parties in Under safelight conditions treatment deemed necessary by a standard method for determining the photosensitive material is safe working conditions.

If there is no change in the density of a simple "fog test" lighting conditions, lighting conditions are generally assumed to be safe, it is often it is incorrect. This material is not suitable for many, especially for black and white and color photographic paper, the image of their area may be more than the unexposed areas Sensitive. Therefore, if the change in the region look unexposed, you may not be aware of unsafe lighting conditions. In addition, photographic products for safety Full light sensitivity may, in accordance safelight exposure before the actual exposure or after acceptance of different, and in some cases given Film or paper type, the number of differences, or even a change in direction is also from batch to batch.

Factors should also be considered that the cumulative effects of continuous exposure. Depending on the exposure of the emulsion formulation type and specific photographic products, these impressions may be sub-additive nature, additive or super-additive in nature.

In general, the spectral characteristics safelight choices need to balance the dark-adapted visual response of the operator and the product of the safety light spectrum response. This standard has nothing to do with this selection.

The purpose of this standard is to determine when the safety light exposure (product of intensity and time) occurs on the characteristics of the image formed on the photosensitive material A detectable impact. Because all stages of virtually all exposures are cumulative, material safety light exposure operation (also Manufacture, inspection, load cameras, tabs, washing and processing, printing, etc.) should be kept to a minimum exposure.

This standard provides an isolated several times and evaluation are possible within the production and use cycle to get exposure for any given safety lamp shine Single exposure method emitted.

GB/T 6846-2008/ISO 8374:2001 OK photography ISO safelight conditions

1 Scope

This standard specifies the determination given photosensitive material can accept from a given safety light does not affect the final image quality maximum exposure the method of light time. Also it provides for recording safety lamp component repair and operating environment.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 11500-2008 photographic density measurements - Part 2. Geometric conditions for transmission density (ISO 5-2:2001, IDT) GB/T 11501-2008 photographic density measurements - Part 3. Spectral conditions (ISO 5-3:1995, IDT) GB/T 12823.4-2008 photographic density measurements - Part 4. Geometric conditions for reflection density (ISO 5-4:1995, IDT)

3 Terms and Definitions

The following terms and definitions apply to this standard.

The net effect of the photographic light-sensitive product acceptance successive exposure generated by exactly equal to the sum of a single exposure of mathematics to predict the effect of conditions.

The relative transmission density area halftone dot percentage of area covered, from the point of the area, the ground area and the calculated point.

Shaped like the number of product-th root involved here are two adjacent safety light exposure value of the square root.

At a given point of the image screen frequency (the number of dots per centimeter) of the composition, the size (value) and variable shape, so as to generate different views Sleep tone level.

Halftone dots have enough steep edge gradient when copying and printing photographic film version of the production is such a hard spot.

When using the method described in this standard to evaluate the offers and generate exposure (adjacent) the minimum perceptible change needs no Detect changes in the geometric mean of the maximum exposure amount half exposure amount of lighting conditions.

Safelight after the photosensitive material to form an image receiving normal exposure.

GB/T 6846-2008/ISO 8374:2001