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Color management in Adobe Illustrator program

Color is the most difficult category in polygraphic process. The color image (for example, from a color photo or a water color), transiting on all stages of handling, since input by means of the scanner or the numeral camera, handling and display on the screen of the monitor and finishing an output to printing devices, undergoes various changes in connection with inevitable converting of color systems. Also that the most sad, these changes can have unpredictable character.

Such situation generates rather conflict relations of all participants of process: the customer who does not wish to see on a polygraphic print the portrait ("краше in фоб put"), the designer who builds a composition on tiny nuances, and the printer who appears "switchman".

Principal causes of this situation it is possible to select three.

	Color perception — difficult psychophysiological process which, probably, never it will be possible to model means as perception is influenced by thousand difficultly considered conditions (age, цветовосприимчивость, the mood, health, lighting and so forth and so forth).
	It is impossible to measure color immediately, as, for example, length. Color is measured as a spectral composition from luminous waves of various intensity and various length. It creates the considerable difficulties in creation of the technical device for reliable measurement.
	The requirement of the full color identity of the original and printing print is in area almost impossible. The matter is that necessity of transmission of the color information forces to use certain "language", to be exact to tell, several languages as at various devices they the input equipment different, for example, and monitors use color model RGB, and output devices — color model CMYK. Hence, "transfer" (converting) from one language on another is required that never does without losses. Besides, the information which has been written down in any type, arrives on the real device which transforms it to the image. And needless to say that the same information will be differently interpreted even by devices of one class. To be convinced of it, it is enough to come into shop of electronics and to look at rows of television receivers, at which identical input signal and noticeable enough distinction in "pictures".

Thus, each stage of operation with the image is characterized by errors of the device and errors of converting ("transfer") of the information from one type in another.

And the task consists in that by any compensatings as much as close to come nearer to impression of identity (analogy to properties at theater: the plywood construction can create the full illusion of real object).

Adobe Illustrator program includes a management system color (СMS - Color Management System) which allows to supervise operation with color on the screen of the monitor and at an output to exterior printing devices.

The management system color uses the standards developed by the International consortium on color (International Color Consortium — ICC) that provides due display of color to the screen of the monitor and due reproduction by a polygraphic method, but also, — the full color unity with Adobe Photoshop programs, Adobe PageMaker and Adobe InDesign.

The management system is based by color on uniform color space which is provided with usage of color model CIE L*a*b.

The second important component of a management system color are color profiles (in other transcription — "profiles") used devices — a file describing correspondence of colors of the input equipment or an output in terms of color model CIE L*a*b.

And, at last, a component providing direct manipulations, "the machine of color correspondence" (color-matching engine) serves so-called. It should receive a color profile of the input equipment, for example the scanner, a color profile of the intermediate device (monitor) if image editing is required, and a color profile of the output device, for example the inkjet printer, and is very rare "press" parameters, and to provide scanning and display on the monitor screen so that the user edited as though the "finite" image, i.e. a printing print. Besides, it allows to imitate partially at least on the screen or by means of color printers the trial press, providing essential saving by preparation for printing issuings of average quality.

Existing management systems color are supplied with enough extensive basis of color profiles for various types of devices (printers) and almost never profiles for standard printing machines, and for table systems there is no possibility to create such profiles with reference to specific devices. And if the management system color does not support any device the user is deprived possibility to build in it in a technological chain.

Before beginning operation over any project, it is necessary to install appropriate profiles for those devices which enter into a chain of handling of color (for Adobe Illustrator program is a monitor and the output device).

For this purpose it is necessary to be convinced available specified file and to execute command Color Settings (Parameters of colors) menu Edit (Editing) which displays the dialog box with the same name (fig. 4.9).

Rice 4.9. Dialog box Color Settings in an enhanced mode

In uncovered list Settings (Setting) variants of adjustments under various tasks, for example, Emulate Photoshop 4 (to Emulate Photoshop 4), Europe Prepress Defaults (Setting by default European standards допечатной preparations) and etc. are presented

	At a choice of variant Emulate Adobe® Illustrator® 6.0 (to Emulate Adobe® Illustrator® 6.0) there is inaccessible command Assign Profile (to Appropriate a profile) menu Edit (Editing) and button Color Management (Color management) in dialog box Print to (Print).
	Variant Color Management Off (to Disconnect color management) can be selected for operation with the device which is not supporting a management system by color.
	The choice of variant Custom (User) allows to install own adjustments and to save them under the arbitrary name in a file with csf extension. After that the file name is displayed in list Settings (Setting).

Flag Advanced Mode (the Expanded setting) provides an output of all setting of a dialog box.

In group Working Spaces (Working color spaces) two uncovered lists RGB and CMYK from which it is possible to select соответствуюшие color profiles for the monitor and the exterior output device which urged to provide document color separation are presented. The choice of this or that variant defines color spanning and converting of one color space in another. The program of adobe Illustrator 9.0 is delivered with standard dial-ups of color profiles.

In group Color Mangement Policies (the Resolution of conflicts of a management system of color) two uncovered lists RGB and CMYK from which it is possible to select following variants also are presented:

	Off to (Disconnect) it is selected, if usage of the data of a management system by the color, imported together with the document is not required. In the new document the data of a color profile also is not saved. If the profile of the opened document does not correspond to a current color profile, its data is deleted and is not saved in the document. If the profile of the opened document corresponds to a current color profile in this case its data is saved in the document.
	Preserve Embedded Profiles (to Save the allocated profiles) it is selected, if it is not required combination of the data of the document with a management system color with the document without a management system of the data, or given other color profiles of a management system color in the same color model. The data of a current color profile is saved in the new document. If the imported color data does not correspond to current color space the profile data is saved by the invariable. If the imported document does not contain the data of a color profile, for document editing the current color space which data, nevertheless, is not saved in the document is used. If the imported color data represents identical color space numeric data are saved.
	Convert to Working Space (to Transform to working color space) it is selected, if the document of a dataful management system color of current color space is required. Thus the data of a color profile is saved in the new document. If the imported color data does not correspond to current color space the document for editing is converted in current color space, and the data of current color space is saved in the document. If the opened document does not contain a color profile the current color space for editing is used, but with the document this data is not saved. If the imported data of a color profile is allocated within one color space, numeric data also are saved.

Using these three variants it is possible to resolve all situations arising at discovery of the document with color parameters or without color parameters.

Initial situation	Possible actions
The document without a color profile is opened	To use working color space for editing, the document not to save, a management system color to disconnect To use working color space for editing, to save the document with parameters of working color space To use other color profile, to save the document with parameters of other color profile
The document with the color profile which is distinct from a work space is opened	To use a necessary profile instead of a current work space for editing, to save the document with parameters of this color profile To transform color space to a current work space, to save the document with work space parameters To eliminate the data of a color profile, to save the document of a dataless management system color
Data of color space is imported	To import and transform numeric data of initial colors to color space of the current document To import and save numerical values of colors of the initial document

Flags Ask When Opening (to Request at discovery) and Ask When Pasting (to Request at gluing in) provide an output to the screen dialogue оконзапросов about necessity of layout of the data of a color profile if profiles of current and imported documents do not correspond each other. Developers of the program recommend to install these flags to have possibility in time to make the decision concerning a demanded color profile.

In group Conversion Options (converting Parameters) lists Engine (the Unit of the machine of color correspondence) and Intent (Method) are presented. It is possible to select one of two variants From the first list:

	The Adobe (ASYA) — is accepted by default, the firm machine of color correspondence of a management system by color;
	Microsoft ICM — the management system color delivered by firm of Microsoft with operating systems Windows 98 or Windows 2000.

In the second list some variants are offered:

	Variant Saturation (Graphics) (With saturation saving (the Schedule)) provides juiciness and saturation of colors partially to the detriment of accuracy of transmission (the variant is suitable for charts, circuits, the conditional images — i.e. the business drawing) and is intended for saving of the relative values of a saturation: the colors which are falling out of color spanning, are replaced with others, entering into color spanning and having identical values of a saturation.
	Variant Perceptual (Images) (Perceptional (Images)) provides playback of photographic images (the variant is suitable for operation with the scanned photo-realistic images) and is intended for saving of the relative color values: relations between colors though actually colors can be others are saved.
	Variant Relative Colorimetric (Relative colorimetric) provides playback invariable those colors which get to color spanning, and changeover of the colors which are falling out of color spanning, by other, having identical values of brightness (the variant is suitable for operation with нефотографическими).
	Variant Absolute Colorimetric (Absolute colorimetric) provides an exception of parameter of a white point at converting of colors. Developers recommend to avoid the given variant.

Flag Use Black Point Compensation (to Use compensating of a black point) provides conversion of dynamic range of color space of an opened file to dynamic range of the current document. When the flag is removed, the dynamic range of initial color space will be transformed to a range of current color space though it is fraught with narrowing of pitch ranges. This flag is most useful, when the first range less than the second.

Change of a color document profile

If needed to change a color profile it is necessary to use command Assign Profile (to Appropriate a profile) menu Edit (Editing). The given command is inaccessible to variant Emulate Adobe Illustrator 6.0 (to Emulate Adobe Illustrator 6.0) in dialog box Color Settings (Color setting).

Nota Bene. It is necessary to mean what to fulfill such procedures it is possible only at the coordination with experts of a service bureau.

As a result dialog box Assign Profile (to Appropriate a profile) (fig. 4.10) which switch Profile (Profile) has following positions opens.

Rice 4.10. Dialog box Assign Profile

	Don't Color Manage This Document (In this document not to control color) provides removal of a current profile from the given document. This position should be selected, if the user is precisely assured that it is necessary to eliminate completely a management system colors.
	Working <цветовоя модель: цветовое пространство>(Work space) provides assignment of current color space to the document without a color profile or having other color space.
	Profile (Profile) provides possibility to appropriate other color profile which is selected from the list, to the document containing the data of other management system by color.

Rice 4.11. An example of flag Embed IIC Profile at saving in format PDF

By default any document with a management system color is saved with layout of the data of a color profile in a format which supports profiles ICC. Such formats concern: AI, PDF, JPEG, TIFF and PSD. At document saving in each of these formats in an appropriate dialog box it is necessary to install flag Embed IIC Profile (to Allocate a color profile) (fig. 4.11).

Adding of a color profile in a management system color

The program of adobe Illustrator 9.0 allows to add in a management system color additional color profiles.

For this purpose it is necessary to copy appropriate files in following folders:

	In operating systems Windows NT/2000 — WinNT\System32\Color;
	In operating system Windows 98 — Windows\System\Color.

Update of profiles

Color characteristics of the input equipment and output change eventually, in this connection periodic update of profiles is required.

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