Here’s the scenario: you purchase a perfect image, you carefully change the settings on your printer like everyone on the Internet says to, you choose the perfect blank, and begin to press it with perfect settings. You count with the timer, impatiently waiting for it to finish. Finally! The wait is over! You take off the butcher paper and remove the print and…there’s an unwanted background that has ruined your project.

What happened? “You used a JPG when you should have used a PNG, because PNGs have transparent backgrounds,” people claimed on their blogs or in online groups where people post for help. Are they right?

No.

So if that’s not correct, what is the answer?

It’s your color settings.

I did a little Googling, which turned into a lot of Googling, about why JPGs have issues with printing a subtle color when PNGs don’t. And as it turns out, PNGs seem to have as many or more problems, even with the vaunted transparent backgrounds. And it’s not just sublimation printers, it’s all printers. And it’s pretty common.

The problem seems to be color settings. One is using ICC files. They affect every color, so if every color needs to be a teeny bit bluer, your white (and transparent, because the print the same) turn a little bluer. Another problem seems to be using an ICC and color correction settings on the printer. Even if the ICC doesn’t change anything, combining that with more color correction corrects the corrections and somehow everythings a little bluer or browner and you’re left with a background that shows up.

This is all true for true white and transparent backgrounds. Sometimes, though, the background actually does have a slight tinge to it, in which case, you need to fix it. It can happen with purchased designs, but is very prevalent with scanned images, as the scanner rarely reads it as perfectly white.

I decided to do a little testing.

Testing Methodology

I created a PNG in the OG PNG creator, Microsoft Paint. Nobody had complained about white not printing white, only the backgrounds, so I put a white rectangle inside a transparent rectangle, so the white is directly next to the transparent. I put a black rectangle just inside the boundaries, in case there’s something smart enough to know that the transparent area inside of the area is part of “the design” but the area outside the black lines is “background.” (There isn’t but doing this solves any problems of inside vs. outside the design. Then I put colored dots in the corners, so I know exactly where the printing should end and blank paper should begin (in the event that it’s the paper’s fault). Then I put tiny dots in the unmarked corners of the white area, just to be sure I could tell the difference between what is supposed to be white and what is supposed to be transparent. I also added the words so I’d remember which is which. I have a white picture with a transparent portion of the design and a transparent background.

I then set out to print the PNG from Paint, Word, GIMP, and/or Inkscape using a variety of printing options. Word also has text options for paragraphs (theoretically transparent) and text boxes (that I set to “no fill”) so I could test that, too. I used text options in each program to document what settings I used. I also used a combination of A-Sub 120, HTVront 120, Hiipoo, and a generic Enfinet paper from Amazon to see if it was a problem with papers. I pressed it all at 390F for 60 seconds, longer and hotter than my usual, to make sure it was cooked enough and that it leaned towards overcooking.

Using the PNG and not resizing it, I printed two images from Word, one with paragraph text, the other with a no-fill text box using my regular settings of Automatic correction (the default setting). I did that on both A-Sub and HTVront papers. I printed from MS Paint (MS stands for Microsoft) with the same default settings — 2 prints, one for the same pressing settings, and one for hotter on Enfinet paper. And then I did two from GIMP, one with the default Automatic correction, the other setting the Hiipoo ICC (since I use Hiipoo ink). I pressed them all at 390F for 60 seconds and, as expected from the sublimation groups, they all came out great, as shown below.

Then I converted it to a JPG. The transparent section was filled in with white, which I confirmed. I printed a lot more of these, since they are the “problems.” Shown from right to left, below, I did the same pair of Word prints with the text box and the paragraph text. I printed it with the defaults on A-Sub and HTVront papers. I printed another Word pair using the ICM setting on the printer Color Correction page which uses the Hiipoo driver. I printed a final Word pair using the “suggested” settings, (Brightness: 9, Contrast: 7, Saturation: 15, Density:4, Adobe RGB, Gamma 2.2). Then I decided to do the PNGs again using the “suggested settings.” (I didn’t do it for ICM). Then a pair of JPGs printed from Paint on HTVront and A-Sub paper. And finally, that last column (first, if you’re reading left-to-right), there’s a GIMP print using the ICM both in the software and as ICM settings, and two from Inkscape using some color management settings and using the “suggested” settings.

As I pressed from right-to-left (it works better in my setup), the first two columns of prints looked perfect. The third column, the pair of Word JPGs printed with the ICM (using the Hiipoo ICC) had a shaded background. Everything else printed well until the very last one. I wanted all of them on the same strip and was running out of room, so I turned one upside down to capture the verbiage to see what happens. Turns out, that top one in the column with three in it also had a shaded background — printed from GIMP with the ICM printer settings.

The ICC used in the ICM is the culprit! If you zoom in, you’ll see that there’s shading all the way to the dots that mark the edge of the image. The white area, the “transparent” area that was converted to white, and the background outside of the black rectangle are all slightly purply-gray. Comparing that to the PNGs — hmmm…I didn’t do a PNG with the ICM.

Then I did the Word pair using one PNG and one JPG. I printed them on all four papers (A-Sub, Enfinet, Hiipoo, and HTVront) and used the ICM setting. Looking closer at the prints, I could see the verrrrry faint coloration in the background. The final press showed every bit of both the JPG and the PNG with a faint color. Both white areas and transparent areas in both the JPG and the PNG are affected.

I’m able to reproduce this using the ICM with every program (Microsoft Paint, Word, GIMP, and Inkscape). It happens on A-Sub, HTVront, Hiipoo, and Enfinet paper. It happens on the white areas in both JPG and PNG formats and the transparent areas on the PNG format. It’s not the format, the paper, or the software. It’s the color settings.

I certainly don’t know everything there is to know about ICCs in the software, so I can’t be sure I’ve bagged every possible combination of problems with white shifting. My Googling indicates that ICCs, especially combined with color correction on the printer, causes color shifting over the entire image. And that’s why I’m a fond user of just Automatic color correction.

Want to know more? Read on for some details that explain my initial skepticism and how things print.

The Background and Detailed Explanation

I first saw this problem posted in a sublimation Facebook group as I first got into sublimation. It was a beautiful image with a background that was discolored. Before reading the answers people gave, my first thought was over-pressed, as it was a tan color. But the shape wasn’t the shape of a press, so that couldn’t be it. My next thought was that somebody used a filter in their software to change the color. Certain that I’d see everyone say something about filters or colors in the software, most everyone was blaming the file format. The summary of their comments was, “You should have used a PNG. PNGs have transparent backgrounds. JPGs have white backgrounds and they will always print off-color.” This made no sense to me. There’s no white ink in the printer, so white is made by leaving a blank. How can there be color where there isn’t any?

How a Printer Prints

When you ask your software to print, it organizes the data to send to the printer. It sends a series of points with the position on the page and the color to print. The driver converts this information into something that the printer understands. The printer reads this data, applies its settings, then puts the colors on the paper.

The colors on your screen are displayed using light, which is a Red-Green-Blue (RGB) color system. The printer uses four inks to make those colors: Cyan, Magenta, Yellow, and Black, or CYMK. (There are some that use 6 or more inks, but for this explanation, we’ll keep it simple with CYMK.) A translation must take place and some colors just can’t be made. But black and white are pretty obvious. RGB colors use the hexidecimal system to name the colors, with 0 being none and FF (or 256 in the decimal system) being the maximum. The color #FFFFFF, or all colors on at the highest level, is white (black is the absence of all colors, or #000000). That translates to CMYK(0,0,0,0) — no cyan, no magenta, no yellow, no black. If the software says, “print white,” then nothing will print.

Color Adjustments

In the professional printing world, accurate colors are imperative. If Coca Cola cans are off by a shade, the blue on a Tiffany box is too blue or too green, or your favorite sports team’s colors print just a little too dark or too light, you’ll know it. These companies work very hard to make sure their colors look perfect, whether it’s printed on paper, cardboard, or an aluminum can. Looking at just paper, there are many colors of “white” paper. On copier paper, you’ll see a brightness. A brightness of 96 is very close to pure white, while a paper of a brightness of 88 will look rather gray next to it. When you put ink, which is not completely opaque, onto different brightnesses of paper, you need to adjust for that to get perfect colors. That’s where .ICC files come in.

The International Color Consortium (ICC) was founded in 1993 by eight companies (Adobe, Agfa, Apple, Kodak, Microsoft, Silicon Graphics, Sun Microsystems, and Taligen) in order to standardize color management, regardless of what device and what operating system you use. Their practices are now the industry standard that all vendors adhere to. That means that a color on an HP laptop running Windows and printing on an Epson can look the same as an Apple computer printing to a Dell or a high-end digital printing press. Each device has a default profile which works pretty well for almost everyone. When professional printers get involved, sometimes they need more control. For example, when Coke develops that advertising on Adobe Illustrator with the exact shade of red and saves it to a PDF to print on the high-end printing press for the box and also printed on the aluminum can, they know it will print properly. They developed a method that allows adjustment for specific combinations of devices, like a particular ink, a particular printer model, and the substrate (paper, cardboard, aluminum can) that’s being printed on. An ICC profile makes these adjustments.

For sublimation, an ICC profile is downloaded from the ink manufacturer’s site. It is usually used by the software, but not all software can use them. It’s typically the high-end graphics programs used by professionals. The operating system can also install it to be called by the printeer using the ICM color correction option (more on that in a bit).

I’ll also note that there are ICC profiles for monitors. It’s important when you want to make the screen match your printer as exactly as possible (colors made from RGB light will never look precisely the same when printed with CMYK ink). HOWEVER, in order to make these work perfectly, you’ll need pricey calibration equipment. If you’re reading this blog for advice, you are likely not a professional graphics artist who needs to ensure that the perfect shade of Tiffany blue, Coke red, or Green Bay Packers green is displayed and printed. So no, don’t go looking for monitor ICCs. If you’re working on a laptop, tablet, or phone, you already have the manufacturer’s ICC and you don’t need another.

Another place to make color adjustments is on the printer. Part of the printer driver that’s downloaded from Epson when you setup your printer is some software that allows the printer driver to make color corrections. It has similar controls as your phone’s photo app, where you can change the brightness, contrast, saturation, and tweak the overall color. These are where the “suggested” settings for sublimation colors are set. This gives an amazing level of control, but you can’t see the results on the screen like you do with your phone’s photo app.

These are the color control, but there is also the ability to “fix photo” (only for photos of one person’s face, though), use the ICM (or the ICC profile installed by the operating system, as noted above), or no adjustment at all. There’s still one more option: the Automatic option on the screen before getting to this screen, which is what I recommend.

All of these color adjustments, both ICC and the printer’s Color Correction page, work on every pixel that’s printed, whether they are a dark color, a bright color, a pastel color, white, or transparent.

Conclusion

White and transparent pixels print exactly the same way, that is to say, no ink gets put down. Unless you use some sort of color adjustment, particularly ICC profiles.