Density

Because a Press Room spectrodensitometer is expensive, the use of the spectrophotometer, which already equips your copier or your proofing system can, thanks to Coraye, serve as a densitometer.

1) Introduction

This feature, proposed by Coraye, can not replace a Press Room densitometer if the spectrophotometer you have does not support the M3 mode (polarizing filter). To be able to measure a wet ink density, your densitometer must be equipped with a polarizing filter to obtain the same density values between a wet ink and a dry ink. For color values (Lab), the measurement must always be performed on dry inks.

However, if you do not have a press room spectrophotometer, but only a press room densitometer, Coraye can, thanks to this feature, allow you to determine the optimum density values corresponding to the Lab values of the primary and secondary colors. recommended by the ISO 12647 standard. Following, a sheet which explain the ISO 12647 norm: ISO 12647

2) Measure yours solid colors

The first thing to do, is to read yours solid colors samples Cyan, Magenta, Yellow and Black e.g. Don't forget to read the Paper, value on an unprinted area, if you have to get the relative density values.

3) Obtain yours density values

To know the density values, you just need to select your color in the left column, then go to the right column to see the values in the Color density area.

Why CMYV and not CMYK ? When you are measuring a density, you are using a densitometer which use Red, Green, and Blue filters to filter Cyan, Magenta, and Yellow density values. But the densitometer can not distinguish the difference between a single black or a composite black. then it will provide us with a density value in relation to a "Visual black".

4) The Status

The density values depend on Status selected: - Status E: A densitometer response which is the accepted standard in Europe for color reflection densitometers. - Status T: Wide band color reflection densitometer response which is the accepted standard in the United States for color reflection densitometers. - Status A: ANSI PH2.18, densitometer response. This is the accepted standard for reflection densitometers for measuring photographic color print. - Status M: Photographic Color Negative Print Density (i.e. color negative, internegative, intermediate, reversal original, reversal intermediate).

Select density status mode

5) Absolute density vs. Relative density

Absolute Density: Density measured with paper density included Relative Density : Density measured without paper included (- Paper) If you you want to know more about this subject: Absolute Density vs. Relative Density

Select density mode

To obtain the relative density values, you have to select "Relative" in the "Mode" area, then you have to drag & drop the Paper reading in the "White Reference" area.

Relative density (-Paper) values

6) Status E vs. Status T

In the field of printing, the difference between the European standard (status E) and the American standard (status T) is the solid yellow color which is not the same. In Europe, they use a yellow ink "lemon" instead of the United States that uses an ink "egg yolk". As a result, the density measurement does not take place on the same frequency zone.

Status E
Status T