Color Matching With RGB Color Charts
Sublimation is like no other technology when it comes to color matching and, as a result, there are some essential steps you should follow to ensure proper color output of vector artwork. Consider this:
- You are working within an RGB environment (your computer monitor, scanner, and digital camera all operate and reproduce colors in RGB mode)
- You are outputting to a CMYK print environment using specialty dye-based sublimation inks
- You are gassing the solid ink particles off the printed page using 400 degrees of heat and medium pressure
When you place your transfer against a blank, polyester-based substrate under a heat press in order to vaporize the inks, you're performing a process unlike any other. That is the nature of sublimation. When the inks turn to a gas state to dye the product, there is a noticeable color shift from transfer paper to final product. The colors will look different on your screen than they do on the printed transfer. The colors will look different on the final product than they do on your screen and transfer. In other words, what you see is not what you get.
How then do you ensure that the color you're working with on the screen and printing out for transfer will be the color you need in the end?
Understanding How Color Works with Sublimation
Believe it or not, it does not matter what your colors look like on your computer monitor or the transfer paper. It matters only how your colors will look after they are sublimated. This is often a difficult concept to follow and one that confuses many sublimation decorators.
Think of color matching sublimation products as similar to painting your house. If you go solely by the color of the swatch at the paint store, there is no guarantee that your finished paint job will match that swatch. On the contrary, it usually looks different after it's been applied to your house and had time to dry. The paint is often lighter in color when wet than after drying. The original color of the surface affects the tint and brightness of the newly painted area . Even how many coats you apply affects the final color. It is not unusual for many homeowners to paint multiple color swatches on a surface and allow them to dry in order to determine what the final color will look like.
In sublimation the final graphic colors are affected by the color of the substrate, the amount of ink you put down on the page and, of course, by the heat and pressure of the dye sublimation process. To ensure you're getting the colors you desire, you'll need to make and use RGB color charts. These sublimated charts will show you what the RGB values you've entered into your design software will look like after you've printed and pressed them on to a sublimation substrate. This will allow you to color match vector elements based on the final result.
Printing RGB Color Charts
We recommend making RGB color charts for both your hard and soft substrate sets. This is easily accomplished by printing out one set of charts for transfer on to white metal and another set for transfer on to a t-shirt or swatch of fabric. Keep in mind that the color of the substrate will affect the transfer color, so if you're going to be working with a lot of colored garments, you might consider devoting colored t-shirts for representative color charts.
Here follows step-by-step instructions for producing color charts.
SubliJet IQ Users Only
SubliJet IQ users can simply and easily print a representative sample of the ColorSure color palettes that are bundled with PowerDriver. Open your PowerDriver print driver from the Printers folder then follow these steps:
- Select your paper size
- Select your substrate (usually Unisub for a sheet of metal and Polyester for fabrics)
- Select your output quality (High Quality recommended)
- Ensure the Mirror button is checked (unless you're making a palette on clear glass or clear film)
- Choose Print Palette, and your color swatches should start printing from your Epson printer
All Sublimation Ink Users
There are a variety of ways to obtain RGB color chart files. First, check with your distributor. They should have files available for both CorelDRAW and Adobe products. The file format EPS (encapsulated post script) is a uniform file format that can be opened within both Corel and Adobe environments.
There are also businesses that can provide you with RGB color swatch files (usually for a fee). If you do an internet search for "RGB color swatch files," you can explore these options.
For CorelDRAW users, there is a useful tool that is bundled with the graphics suite that allows you to make your own printable RGB (or any color mode) color swatches. The language varies by version (recommend 12 through X4), but the steps to access this feature are as follows:
- Activate any RGB color palette (Window / Color Palettes / select the palettes you want to open)
- From the Tools menu, select Visual Basic, then Play
- From the "Macros in" pull-down, select Global Macros
- Select CorelMacros.CreateColorSwatch and choose to Run
- Select your active palette from the pull-down menu
- Change the spacing to something more conducive to a full sheet of color swatches (like 8)
- Choose OK
This macro will now create a CorelDRAW file on 8.5" x 11" pages suitable for printing.
Producing RGB Color Charts
As mentioned earlier, we recommend making at least two sets of RGB color swatch charts: one set for hard substrates using white metal and one set for soft substrates using white polyester fabric (t-shirt or piece of polyester material). Once you've printed the RGB color charts transfers, you need only press them on to the two types of substrates.
Under a heat press, face the mirrored transfer against the blank substrate. To avoid ghosting the image through shifting when opening the press, you should adhere the transfer to the substrate using heat resistant tape. Place the substrate under your heat press, transfer side up, and press for the allotted time based on the material. White Unisub metal usually takes 60 seconds at 400 degrees with medium pressure. Polyester fabrics can be pressed at 45 to 50 seconds at 390 to 400 degrees using medium pressure. For the best results, visit the substrate manufacturer's web site for the ideal pressing times and instructions.
- From you graphics software, print the color chart using the ideal settings for the substrate (these settings are explained with the installation guides that you downloaded before setting up your printer)
- Marry the mirrored transfer face down toward the blank substrate and secure using heat resistant tape
- Place the substrate under your heat press, place a piece of throwaway paper over the top and press according to the substrate manufacturer's recommended guidelines
- Carefully remove the substrate and peel off transfer when the pressing time is complete
- You now have a representative RGB color chart showing how specific RGB values will look after pressing
Using Your RGB Color Charts
After you've made your color charts on a hard substrate and a soft substrate, you are now able to determine what your colors will look like after being pressed. To hit specific spot colors, simply change the RGB value of vector graphics (e.g. logos, text, etc.), print it using your sublimation system and transfer the image using the same time, temperature and pressure you used to make the RGB color chart.