What is Color Management?

A Color Management System (CMS) is the calibration of your input devices with your output devices to produce consistent, predictable color. Examples of input devices are scanners and digital cameras. Output devices include your monitor, desktop printer, film recorder, and even the printed page.

The monitor is a significant importance in this calibration process as it serves as a preview of your finished piece. The promise of color management is WYSIWYG (What you see is what you get).

Scanner/digital camera characterization is accomplished by scanning a color target into the computer. The color values of the scan are compared to known values and a translation table is produced. These tables are called ICC (International Color Consortium) Device Profiles. Similar profiles are produced from every device in the system. Device profiles can be obtained from the manufacturers hardware devices or produced by you using specialized software.

To calibrate your monitor, requires a color measuring device that attaches to the screen to measure color (colorimeter). These devices come bundled with software packages or can be obtained separately. The new inexpensive versions (under $1,000) of these devices are responsible for the availability of color management to the individual or small business. Previously, such devices were over $10,000.

Color Management involves specialized software that communicates the calibration of each device to the computer which makes adjustments to match the color gamut (palette or range of colors a device can produce) of one device to another.

Monitor Calibration

There is a basic difference between a color monitor's display and that of a reflection print. These differences are similar to that of an original transparency, and the print reproduction of it.

The monitor, like the transparency, has a dynamic range that far exceeds that of a reflection print.

Color calibration is basically matching your monitor to look like your print job, whether it's photo or press work.

Advances are being made in this area everyday.

There are conflicting proprietary standards, but the dust is settling.

Image File Compression

• Compression is used to make data smaller. It can provide excellent efficiency for storage, but is especially appreciated when images must move through the net, our pipeline to the future.
• Generally, compression is a trade off of image quality vs. file size. There are compression algorithms that are better at compressing flat color graphics than photos.
• Jpeg is the standard in photographic image compression. It is capable of 16 million colors and a full 24 bits of data per pixel.
• Jpeg has an adjustable setting, when saved, that allows decisions on quality verses file size.

 

Resolution

• Image resolution is the amount of image detail saved in the file.
• Similar to photo resolution, where the finer the grain the higher the resolution possible.
• The unit of photo digital resolution is the Pixel (Picture Element)
• Resolution is generally measured in Pixels per Inch.

Double the size is over 4 times the pixels
Size in Inches	Resolution (pixels per inch)	RGB File Size	CMYK File Size
1 x 1	100 ppi	30 k	40 k
2 x 2	100 ppi	118 k	157 k
CMYK adds an additional 33% to the file size

Standard display on computer monitor is 72 ppi.

Sometimes, Dots per Inch (dpi) is used interchangeably, but it's more of a measure of output resolution where devices have fixed dot sizes.

A Pixel, on the other hand, can be any size.

Bit depth, as in 24 bits/pixel, is the amount of information about the Pixel. It's color, location

Generally, for press work 300 ppi is good.

Some standard file sizes for standard offset print production
Size in Inches	Resolution (pixels per inch)	RGB File Size	CMYK File Size
4 x 5	300 ppi	5.15 MB	6.87 MB
5 x 7	300 ppi	9.01 MB	12 MB
8 x 10	300 ppi	20.6 MB	27.5 MB
11 x 14	300 ppi	39.7 MB	52.9 MB
16 x 20	300 ppi	82.4 MB	109.9 MB

In photo, it varies with the final magnification, original image detail, and final viewing distance. It is entirely subjective, just like 35mm vs. Medium or large format preferences

File Formats

• TIFF or Tagged Image File format. Originally invented by Aldus (now owned by Adobe)
• Jpeg (Joint Photographic Experts Group)

TIFF file format

TIFF stands for Tagged Image File Format. It is a compressed file format originally developed by Aldus (now owned by Adobe) for their PageMaker® software. It evolved into a universal standard.

Photoshop format

Adobe Photoshop, the defacto standard for photo image editing software, is available on a multitude of computer platforms.

• Mac
• Windows
• SGI (Silicon Graphics)

And, all are interchangable including layer and masking information. Photoshop® file format is also a very good compression format

EPS file format

Encapsulated Postscript is a file format primarily for vector graphics.

• It is capable of saving both type, type outlines, mask outlines, and pixel information.
• It is not a compressed format.
• It can save screen and calibration information along with the picture data.
• Photo images included are not directly editable.
• It's universal, works in all page layout programs.