BreadCrumbs: DTG Graphic Process

DTG Graphic Process

From Luke Jackson

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Revision as of 14:43, 15 June 2007

1 Summary
2 Requirements
3 Knowledgebase
4 Adobe Photoshop CS2

Summary

This process details the steps required to process graphics for printing on the Kornit direct to garment printers.

Requirements

Adobe Photoshop CS2+
- Basic Usage Knowledge
Onyx ProductionHouse 7+
- Kornit 1bit Printer Driver

Knowledgebase

In order to optimize graphics for printing on the Kronit, it is important to understand the following points:

Layers
Channels
Spot Colors
Solidity
Opacity
Color Profiles
.tif Graphic File Format

Layers

Image:Dtg layers.jpg

Transparent areas on a layer let you see through to the layers below.

Layers allow you to work on one element of an image without disturbing the others. Think of layers as sheets of acetate stacked one on top of the other. You can see through transparent areas of a layer to the layers below. You can change the composition of an image by changing the order and attributes of layers. In addition, special features such as adjustment layers, fill layers, and layer styles let you create sophisticated effects.

A new image in Photoshop has a single layer. The number of additional layers, layer effects, and layer sets you can add to an image is limited only by your computer’s memory. Layer groups help you organize and manage layers. You can use groups to arrange your layers in a logical order and to reduce clutter in the Layers palette. You can nest groups within other groups. You can also use groups to apply attributes and masks to multiple layers simultaneously.

For our process it is important to create a new layer and delete the background layer. This is because you cannot change the stacking order of a background, its blending mode, or its opacity. However, you can convert a background to a regular layer but it is better practice to just delete it and create a new empty layer to work on.

Channels

Channels are grayscale images that store different types of information:

Color information channels are created automatically when you open a new image. The image’s color mode determines the number of color channels created. For example, an RGB image has a channel for each color (red, green, and blue) plus a composite channel used for editing the image.
Alpha channels store selections as grayscale images. You can add alpha channels to create and store masks, which let you manipulate or protect parts of an image.
Spot color channels specify additional plates for printing with spot color inks.

An image can have up to 56 channels. The file size required for a channel depends on the pixel information in the channel. Certain file formats, including TIFF and Photoshop formats, compress channel information and can save space. The size of an uncompressed file, including alpha channels and layers, appears as the rightmost value in the status bar at the bottom of the window when you choose Document Sizes from the pop-up menu.

Note: As long as you save a file in a format supporting the image’s color mode, the color channels are preserved. Alpha channels are preserved only when you save a file in Photoshop, PDF, PICT, Pixar, TIFF, or raw formats. DCS 2.0 format preserves only spot channels. Saving in other formats may cause channel information to be discarded.

Spot Colors

Spot colors are special premixed inks used instead of, or in addition to, the process color (CMYK) inks. Each spot color requires its own plate on the press. (Because a varnish requires a separate plate, it is considered a spot color, too.)

If you are planning to print an image with spot colors, you need to create spot channels to store the colors. To export spot channels, save the file in DCS 2.0 format or PDF.

Note the following when working with spot colors:

For spot color graphics that have crisp edges and knock out the underlying image, consider creating the additional artwork in a page‑layout or illustration application.
To apply spot color as a tint throughout an image, convert the image to Duotone mode and apply the spot color to one of the duotone plates. You can use up to four spot colors, one per plate.
The names of the spot colors are printed on the separations.
Spot colors are overprinted on top of the fully composited image. Each spot color is printed in the order it appears in the Channels palette, with the topmost channel printing as the topmost spot color.
You cannot move spot colors above a default channel in the Channels palette except in Multichannel mode.
Spot colors cannot be applied to individual layers.
Printing an image with a spot color channel to a composite color printer will print the spot color at an opacity indicated by the Solidity setting.
You can merge spot channels with color channels, splitting the spot color into its color channel components.

Solidity

Image:Dtg solidity.jpg

Solidity at 100% and solidity at 50%

Solidity, is a value between 0% and 100%. This option lets you simulate on-screen the density of the printed spot color. A value of 100% simulates an ink that completely covers the inks beneath (such as a metallic ink); 0% simulates a transparent ink that completely reveals the inks beneath (such as a clear varnish). You can also use this option to see where an otherwise transparent spot color (such as a varnish) will appear.

Note: The Solidity and color choice options affect only the on-screen preview and the composite print. They have no effect on the printed separations.

Opacity

Layer Opacity

A layer’s opacity determines to what degree it obscures or reveals the layer beneath it. A layer with 1% opacity appears nearly transparent, whereas one with 100% opacity appears completely opaque.

Note: You cannot change the opacity of a background layer or a locked layer. You can, however, convert a background layer to a regular layer, which does support transparency. See To convert a background into a layer.

Select a layer or group in the Layers palette.
Do one of the following:
- In the Layers palette, enter a value in the Opacity text box or drag the Opacity pop‑up slider.
- Choose Layer > Layer Style > Blending Options. Enter a value in the Opacity text box or drag the Opacity pop‑up slider.
- Select the Move tool and type a number indicating the percentage of opacity.

Fill Opacity

In addition to setting opacity, which affects any layer styles and blending modes applied to the layer, you can specify a fill opacity for layers. Fill opacity affects pixels painted in a layer or shapes drawn on a layer without affecting the opacity of any layer effects that have been applied to the layer.

Do one of the following:

In the Layers palette, enter a value in the Fill Opacity text box or drag the Fill Opacity pop‑up slider.
Double-click a layer thumbnail, choose Layer > Layer Style > Blending Options.

Note: To view blending options for a text layer, choose Layer > Layer Style > Blending Options, or choose Blending Options from the Add A Layer Style button at the bottom of the Layers palette. Enter a value in the Fill Opacity text box.

Color Profiles

Image:Dtg color profiles.jpg

Managing color with profiles

Precise, consistent color management requires accurate ICC-compliant profiles of all of your color devices. For example, without an accurate scanner profile, a perfectly scanned image may appear incorrect in another program, simply due to any difference between the scanner and the program displaying the image. This misleading representation may cause you to make unnecessary, time-wasting, and potentially damaging “corrections” to an already satisfactory image. With an accurate profile, a program importing the image can correct for any device differences and display a scan’s actual colors.

A color management system uses the following kinds of profiles:

Monitor profiles Describe how the monitor is currently reproducing color. This is the first profile you should create because it is absolutely essential for managing color. If what you see on your monitor is not representative of the actual colors in your document, you will not be able to maintain color consistency. (See To calibrate and profile your monitor.)

Input device profiles Describe what colors an input device is capable of capturing or scanning. If your digital camera offers a choice of profiles, Adobe recommends that you select Adobe RGB. Otherwise, use sRGB (which is the default for most cameras). Advanced users may also consider using different profiles for different light sources. For scanner profiles, some photographers create separate profiles for each type or brand of film scanned on a scanner.

Output device profiles Describe the color space of output devices like desktop printers and a printing press. The color management system uses output device profiles to properly map the colors in an document to the colors within the gamut of an output device’s color space. The output profile should also take into consideration specific printing conditions, such as the type of paper and ink. For example, glossy paper is capable of displaying a different range of colors than a matte paper.

Most printer drivers come with built-in color profiles. It’s a good idea to try these profiles before you invest in custom profiles. For information on how to print using the built-in profiles, see Letting the printer determine colors when printing. For information on how to obtain custom profiles, see Obtaining custom profiles for desktop printers.

Document profiles Define the specific RGB or CMYK color space of a document. By assigning, or tagging, a document with a profile, the application provides a definition of actual color appearances in the document. For example, R=127, G=12, B=107 is just a set of numbers that different devices will display differently. But when tagged with the AdobeRGB color space, these numbers specify an actual color or wavelength of light; in this case, a specific color of purple.

When color management is on, Adobe applications automatically assign new documents a profile based on Working Space options in the Color Settings dialog box. Documents without associated profiles are known as untagged and contain only raw color numbers. When working with untagged documents, Adobe applications use the current working space profile to display and edit colors. (See About color working spaces.)

Tip: To view the current document profile, select Document Color Profile in the status bar.

Managing color with profiles

A. Profiles describe the color spaces of the input device and the document. B. Using the profiles’ descriptions, the color management system identifies the document’s actual colors. C. The monitor’s profile tells the color management system how to translate the numeric values to the monitor’s color space. D. Using the output device’s profile, the color management system translates the document’s numeric values to the color values of the output device so the actual colors are printed.

.tif Graphic File Format

Tagged-Image File Format (TIFF, TIF) is used to exchange files between applications and computer platforms. TIFF is a flexible bitmap image format supported by virtually all paint, image-editing, and page-layout applications. Also, virtually all desktop scanners can produce TIFF images. TIFF documents have a maximum file size of 4 GB. Photoshop CS supports large documents saved in TIFF format. However, most other applications and older versions of Photoshop do not support documents with file sizes greater than 2 GB.

TIFF format supports CMYK, RGB, Lab, Indexed Color, and Grayscale images with alpha channels and Bitmap mode images without alpha channels. Photoshop can save layers in a TIFF file; however, if you open the file in another application, only the flattened image is visible. Photoshop can also save annotations, transparency, and multiresolution pyramid data in TIFF format.

In Photoshop, TIFF image files have a bit depth of 8, 16, or 32 bits per channel. You can save high dynamic range images as 32‑bits-per-channel TIFF files.

Adobe Photoshop CS2

Retrieved from "http://wiki.ljackson.us/DTG_Graphic_Process"

 * Opacity
 * Color Profiles
-* .tif Graphics File Format
+* .tif Graphic File Format
 === Layers ===
 === Opacity ===
+'''Layer Opacity'''
 A layer’s opacity determines to what degree it obscures or reveals the layer beneath it. A layer with 1% opacity appears nearly transparent, whereas one with 100% opacity appears completely opaque.
 ** Choose Layer > Layer Style > Blending Options. Enter a value in the Opacity text box or drag the Opacity pop‑up slider.
 ** Select the Move tool and type a number indicating the percentage of opacity.
+'''Fill Opacity'''
 In addition to setting opacity, which affects any layer styles and blending modes applied to the layer, you can specify a fill opacity for layers. Fill opacity affects pixels painted in a layer or shapes drawn on a layer without affecting the opacity of any layer effects that have been applied to the layer.
 === Color Profiles ===
+[[Image:Dtg_color_profiles.jpg|frame|Managing color with profiles]]
 Precise, consistent color management requires accurate ICC-compliant profiles of all of your color devices. For example, without an accurate scanner profile, a perfectly scanned image may appear incorrect in another program, simply due to any difference between the scanner and the program displaying the image. This misleading representation may cause you to make unnecessary, time-wasting, and potentially damaging “corrections” to an already satisfactory image. With an accurate profile, a program importing the image can correct for any device differences and display a scan’s actual colors.
 '''Tip:''' To view the current document profile, select Document Color Profile in the status bar.
-== Adobe Photoshop CS2 ==
+'''Managing color with profiles'''
+'''A.''' Profiles describe the color spaces of the input device and the document.   '''B.''' Using the profiles’ descriptions, the color management system identifies the document’s actual colors.   '''C.''' The monitor’s profile tells the color management system how to translate the numeric values to the monitor’s color space.  '''D.''' Using the output device’s profile, the color management system translates the document’s numeric values to the color values of the output device so the actual colors are printed.
-[[Category:Graphics]]
+=== .tif Graphic File Format ===
+Tagged-Image File Format (TIFF, TIF) is used to exchange files between applications and computer platforms. TIFF is a flexible bitmap image format supported by virtually all paint, image-editing, and page-layout applications. Also, virtually all desktop scanners can produce TIFF images. TIFF documents have a maximum file size of 4 GB. Photoshop CS supports large documents saved in TIFF format. However, most other applications and older versions of Photoshop do not support documents with file sizes greater than 2 GB.
+TIFF format supports CMYK, RGB, Lab, Indexed Color, and Grayscale images with alpha channels and Bitmap mode images without alpha channels. Photoshop can save layers in a TIFF file; however, if you open the file in another application, only the flattened image is visible. Photoshop can also save annotations, transparency, and multiresolution pyramid data in TIFF format.
+In Photoshop, TIFF image files have a bit depth of 8, 16, or 32 bits per channel. You can save high dynamic range images as 32‑bits-per-channel TIFF files.
+== Adobe Photoshop CS2 ==