Below is a detailed version of the article I wrote for Impressions Magazine.
PREPARE ART FOR DTG PRINTING
Unless you are a master screen printer with years of production and art separation experience, one of the best ways to achieve vibrant full color prints is with digital printing. Starting with the right type of art is critical for “wow factor” results. In this article I am going to teach you the basics types of art, what formats to use and how to optimize for files for best results.
Raster and Vector Art.
Raster art is pixel based, meaning resolution is dependent on how many pixels fit within a square inch or dpi (dots per inch). The higher the dpi the more clear and higher quality the image. Raster art is made in Adobe Photoshop and Corel Photo or Paint.
With raster art you cannot increase low resolution art, you can only decrease in resolution. For example you can’t take 72dpi art and make it 300dpi but you can take 300dpi art and make it 72dpi.
A 72dpi image at 10”x8” is not sufficient enough quality for printing on a garment. The image will be too pixelated and not allow for crisp clear printing and If you try and make the image larger, the resolution will degrade even further.
A 300dpi image at 10”x8” is plenty sufficient and also allows you the opportunity to increase the dimensions of the image while still maintaining descent quality. It’s important to remember the larger you make a raster image dimensions, the more the image quality will degrade.
Now there is one exception regarding resolution. If you have an image with extremely large dimensions, say 3,200 pixels by 2,400 pixels (45”x34”) at 72dpi, there is sufficient dpi at these large scales that you can reduce the image dimensions to fit within your print perimeters and still maintain a high quality print.
Recap of raster art.
Design your art at high resolution and large file dimensions. This gives you the most versatile platform for maintaining a high quality print. I like 300dpi and around 14”x16” for a standard front or back print.
Avoid low resolution, small dimension art.
It’s okay to use very large dimension art of low resolution if you plan to shrink the art down.
Vector art is made in Adobe Illustrator or CorelDRAW. Vectors are created using mathematic equations within points, lines, and shapes to create images that maintain clarity when scaled, up or down, without any loss of quality.
Vector art is extremely common and many designers prefer using vector programs, but most DTG software will not read vector art files, therefore you must export your vector art to a raster format.
When saving art for DTG printing always assume you will need a transparent background. To print on dark garments with white ink, your image must have a transparent background.
Most DTG software will let accept .JPG, .PNG, .TIFF and often other formats. JPG is only good on light garments that do not use white ink, otherwise the background of the image will print white ink.
You must save or export your files to PNG or TIFF to preserve transparency. I recommend saving your print files as PNG. PNG allows you to preserve transparency, maintains resolution, and is a universal format.
To save your print ready images in Photoshop or Paint, go to file>save as>png. In Illustrator or Draw, you must export your image, go to file>export>png.
If you are creating your own artwork in a raster program always ensure you have a transparent background layer. A transparent background looks like a white and grey grid. If you see a white or colored background and you do not see the transparency grid, your printer will print the solid background on dark garments.
When exporting from a vector program, size the art to the approximate print dimensions, and export as .PNG at 300dpi.
RGB, CMYK, and File Optimization:
RGB is an additive color model where Red, Green, and Blue light is added together to form a color gamut. RGB input is typically used on most all electronic devices, TV, Computer Screens, etc. RGB offers a larger color gamut than CMYK.
CMYK is a subtractive process requiring a white background using 4 colors, Cyan, Magenta, Yellow, and the Key (black ink). CMYK is the standard process for most all common digital printing processes. Most all DTG printers print with CMYK + White ink.
Even though your printer prints in CMYK, its best practice to design in RGB for all print applications for the following reasons.
CMYK file sizes are about 25% larger than RGB.
Most filters and image enhancements are only available in RGB color mode.
Web art and most printers require RGB color mode so there is no need for conversion from CMYK.
Matthew Rhome, DTG Business Development, Fabric Imaging for Epson America, helps explain CMYK printing and RGB art. “The Epson SureColor F2000 DTG Printer is specifically designed to enhance the CMYK color gamut to achieve as close to the RGB spectrum as possible. Because of this, the SC-F2000 offers some of the industries most vibrant color values”.
The Epson SC-F2000 is a perfect example, the Epson F2000 accepts (SWOP2 standard), however we don’t generally recommend it as there is no support for transparency in CMYK data (For Garment Creator)
Now because we are working in a vibrant spectrum like RGB, let’s talk about some functions you can use to optimize your artwork for maximum quality.
This list below was given to me by Great Dane Graphics and is set up for use in Photoshop; all of the functions should available in Corel Paint. I highly recommend following these instructions for all your complex art before you print.
- In Photoshop go to Image>Adjustments>Selective Color. Change the “Colors” pop-down menu to “Neutrals” and change all the values to between 3-8.
- Go to Image>Adjustments>Hue/Saturation and move the Saturation slider to the right. It can typically be moved to anywhere within the 0-45 range. Move it to the right as much as needed to saturate your colors without becoming over saturated and flat.
- Go to Image> Adjustments>Brightness/Contrast, and move the Contrast to 5. If you have a newer version of Photoshop you will see a “Use Legacy” check box, be sure to check it on.
- Next go to Image>Adjustments>Levels. Holding down your Option Key, move the black slider on the left side of the Input Levels to the right until you see black pixels show on your screen. Then move the white slider on the right side to the left until you see white pixels show on your screen. By doing this you are setting your black and white points in your image, and helping to reduce any “muddiness” in the colors of your layout.
Go to Image>Mode>Lab Color. Open your Channels palette and click on he Lightness channel to select it.
With the Lightness channel selected, go to Filter>Sharpen>Unsharp Mask. Move the amount slider to the right. We can really crank up the sharpness because we are only working with the luminosity of our image, not the color.
As you can see the color values are way up, the image is less muddy, and noticeably more crisp and clear.
Recap of preparing art for DTG Printing:
- Look for and design high resolution art. 300dpi is best OR 72dpi with extremely large image dimensions.
- Save art from Photoshop or export from Illustrator, to ensure transparent background, PNG preferably.
- Design or convert art to RGB.
- Follow the instructions from Great Dane Graphics for pre-printing file optimization.