Monitor to correct image tone shift control

Consecutive transfer of pictures into halftone prints requires many links, such as scanning, display, conversion from RGB mode to CMYK mode, filming, proofing, printing, printing, etc. There are many variable factors that affect the effect of tone reproduction. Errors in any one of the links will lead to abandoning the previous work. To control the tonal reproduction of the image, there is a perfect effect. It is necessary to eliminate many bad factors and take necessary measures such as parameter detection and correction for each link. This article on the PC on the relevant settings, so that pre-press production meet the actual production requirements.

Display correction

Image correction in Photoshop 6.0. In order to ensure that the hue displayed on the monitor screen is predictable, two things need to be taken care of when correcting the monitor: the ambient light source should be standard, professional fluorescent lamps should be used, and the sample light source of the printing shop should be the same; after the monitor is turned on , After a period of time, at least half an hour after the display is stable and then correct.

1. Determine the screen color space with Gamma settings

A Gamma program is bundled in Photoshop 6.0 and can be found in the Control Panel. Through the setting of Gamma, a device description file conforming to the ICC standard can be generated, and there are two ways of centralized setting or following the guide. Figure 1 Gamma control panel, we can load the known ICC profile as a starting point, we can also rename a file, we can adjust the brightness and contrast in this palette, select the model of the display phosphor, and set the Gamma value And fine-tuning, white-field settings.

If you follow the wizard to set, follow the steps below:

1 Adjust the brightness and contrast of the monitor. Adjust the contrast to the maximum and adjust the brightness so that the middle cube is as dark as possible.

2 Select the type of phosphor used by the monitor. Most monitors use the Triniton standard.

3Gamma numerical settings and fine-tuning. The gamma value is essentially the overall correction value of the display contrast. If it is used for print setting, it is set to 2.2, because the density value reflected on the paper according to the printing ink is basically this value. Then fine-tune the slider so that the gray value of the central area of ​​the square appears to be consistent with the surrounding gray values. When performing fine adjustment, a single grayscale block or RGB three-color grayscale block can be displayed to adjust each color.

4 Determine the white field color temperature of the displayed hardware. The white field value essentially refers to the white appearance of the display. The white field color temperature of the display should be the same as the ambient light source color temperature, ie D65. You can also click on "Measure" to select it visually. The screen will turn black and three squares will appear. At this time, select the most neutral one. Setting the display to a cold or warm color temperature by tapping the left or right squares; setting is complete when you tap the middle square.

5 Work color temperature adjustment of the white field. You can select a value that is the same as the hardware setting of the monitor to make it match the hardware setting or select a different value to adjust the display of the monitor.

6 Complete the gamma setting. Select Before or After to observe the display changes before and after the gamma setting. Enter a file name, tap Done to save the settings for later recall.

2.RGB settings determine Photoshop working color space

Through the Photoshop 6.0 editor - color settings - custom RGB settings can be set to some of the most basic parameters of the monitor. The setting parameters you make are the same as the ones set by Gamma, making the Photoshop color space and monitor color space consistent.