T-shirt colour matching – the pill for the Pantone migraine

Marshall Atkinson tackles every decorator’s nemesis: perfectly matching colours to the exact Pantone shade. If there’s one thing that is frustrating in the decorated apparel industry, it’s Pantone colour matching. Some customers are happy with ‘close’, some customers demand a dead-on match. Do it right every time and you won’t have to worry.

So here’s the rule: regardless of what was mixed in the bucket, what the shirt fabric content is, what press you are printing with, whether you have an underbase or not, who is printing the job, or any other excuse, the Pantone Matching System (PMS) colour called out must match at the end of the dryer belt – one hundred percent of the time.

Below are some of the things I’ve learned these past few decades. Maybe they will help. Do I know everything? Nope. I’m still learning too, even after a few decades in this business…

Use a new Pantone book

That five-year-old (or older) book? It’s junk. Colours fade, even if you’ve been really careful. Sure, these books are really expensive, but not as expensive as replacing an order because you are a shade off and don’t know it. At a minimum, replace these once every two years. You need a new one just to keep up and be relevant.

Get a neutral light source for colour review

Let’s face it, the lighting in your shop sucks for any type of exact colour management. It’s awful. There’s probably a big difference between the bluish cast out in production and the yellowish cast in the front office. Sunlight works well usually, or you can build a custom light box pretty cheaply. Here are some plans I found: www.wikihow. com/Create-an-Inexpensive-Photography-Lightbox. At a pinch, use the flashlight feature on your smartphone.

First mix the ink correctly

Assuming you aren’t buying the colour already made (which is more expensive), you just need to be sure you are following the recipe exactly. Most colours are mixed with a combination of a base and several pigments. How much you put in can have a dramatic effect on the final colour if you don’t do it right. When they say 256.78 grams of a pigment, you need to put exactly that in the bucket. Do that and it will come out correctly, as specified by the ink manufacturer, every time. Will it work for every application? No. Sometimes you need to adjust, and the problem is usually related to opacity rather than the hue straying off in another direction.

Document what you are doing

This means taking notes. Why? Six months after you used that ink concoction you dreamed up for that fantastic design, you are out of ink and need to mix another bucket. Now you can’t seem to get it right and you have a print crew standing around doing nothing. Talk about stress. However, if you jotted down the recipe and entered that into your ink notebook, or production system, or ink software, then you can replicate that coolness easily.

Make sure your mesh choices are correct

A lower number on your mesh count means you will be printing more ink on the shirt. A higher number on your mesh count means you will be printing less. With some colours there is a noticeable difference between the final printed colour between different mesh counts with ink from the same bucket.

In your shop, who determines the mesh count? If you are constantly reburning screens on different mesh counts during a production run because you don’t like the printed result, you need to pick a different person or invest in some training.

Make sure your screens are built properly

You want a solid foundation for printing, with an eye out for good tension and proper emulsion coating. Screen printing is a mechanical process and the screen is one of the keystones to the entire operation. If your screen room staff are clean, neat, organised and methodical in their approach to ensuring your screens are perfectly ready for printing, you have just solved half of the most common problems in printing. I can’t emphasise this enough.

Want to make the lives of your employees better? Automate as much of these steps as possible. If you are doing any sort of volume, this pays dividends in lower costs, happier employees, better quality screens, and problems solved.

Look to your tension for your screens. Measure and keep track. At a minimum, somewhere between 20 and 25 Newtons is your baseline. Lower tensioned screens mean you need to place more pressure on the squeegee to get the ink to clear, and this can affect your deposit – which ultimately can affect the ink hue in the image.

Also, make sure your screen coating is standardised as much as possible to get consistent emulsion over mesh (EOM). If you can afford it, get an auto-coater so this task is standardised and every screen is made exactly the same.

Build your art files correctly

How will your art file make the Pantone colour choice look wrong? Easy. Think about the choices you make when creating the file. Let’s say you are printing a bright PMS 186 red on a black shirt. With an underbase it looks red. Without an underbase it will appear maroon.

You can easily have a gradient underbase of white from 100% to 0% under a solid block of PMS 186, and the actual print will appear to fade from red to maroon to black. However, this won’t work for all colours: in the same example, if we use a crisp light blue PMS 297 on a yellow T-shirt, the colour block will fade from light blue to ultimately a greenish colour, as the light blue may not have enough opacity or contrast to block out the yellow of the shirt totally.

Not all art files are created by people that know what they are doing. Don’t just separate the file like a mindless robot. Go through it and look for problems with a quality control step in your art department.

What’s the deal with the under base?

First, it doesn’t always have to be white. You can use other colours, even one that’s in the design somewhere else. It all depends on the colour selection for the job. After white, the most common underbase colour is a grey. For example, a white underbase can sometimes make a red colour like PMS 202 look pinkish. If you use a grey like PMS 428, you may get a better result. But let’s say you have a PMS 109 on the art too. That underbase grey might affect the yellow, so it appears a tad green. Maybe a tan underbase is the answer then. This is where your note-taking can pay off as you can create your own reference guide for colours that work for you.

For darker colours you probably don’t need an underbase when printing on coloured shirts. However, that isn’t always the case as the darker the shirt colour, the more of an impact an underbase can have in keeping your Pantone colours true on the final print.

Squeegees

After the importance of a properly tensioned screen, the next biggest factor in printing is always going to be the squeegee. This is because how the squeegee is used with the screen directly affects the performance of the ink. Downward squeegee pressure, the hardness of the squeegee, and even the angle of the squeegee blade, can all influence how an ink colour will print on a shirt. A harder squeegee will lay down less ink than a softer one. Usually, if there is some sort of colour challenge on press and the hue is a little light, changing the squeegee to a softer rubber can help lay down more ink and nudge the opacity of the ink deposit enough so that you can arrive at your colour target.

Print order

There are many theories on print order when it comes to screen printing. Some printers will set up according to the percentage of ink going down, while others will always set up light to dark. There are also reasons to set up according to how the artist separates the image, as maybe there are halftones that have to print over another colour, for example. Occasionally a colour will lighten up during printing because it is getting ‘stepped on’ by the other colours during the print run and the wet ink is transferring to the back of the screen of other colours in the sequence. This detrimental effect can be stopped by flash curing the colour in question after printing it, or moving the screen in the print order.

Don’t be afraid to move some screens around in the print order if you feel that something might work. Before you break down the screen and reposition, run a test and print them with the new order idea to see if you get the results you want. If it doesn’t work, you haven’t lost anything. Also, especially for jobs with a lot of colours, just print a few screens to see what effect the change will have on the colours in question.

Marshall’s ‘On Press Colour Challenge’ checklist

When you have a problem on press with colour matching, use this quick checklist to help narrow down the reason and determine how to resolve the issue quickly. Remember, regardless of what is in the bucket, the ink must match the Pantone book at the end of the dryer. Whatever you do, make sure you take notes and record what happens in a log book or your system so you can replicate the job again for a reorder.

1. Doublecheck that you have the right ink colour. More than once I’ve seen the wrong bucket pulled as someone has read the colour name incorrectly.

2. Make sure you are reviewing the ink colour with a newer Pantone book and with a neutral light source. Both are critical.

3. I hate to write this, but as I’ve run into this several times in my career I feel obligated to do so: You absolutely cannot match any printed ink colour to your computer monitor or a colour paper print out. You know better…right?

4. Always only change one thing at a time. For example, don’t change a squeegee and the print order at the same time. Do one, then the other. Maybe your first change solves the problem. Test after each change and see what happens.

5. If the colour problem is due to printing over an underbase, the ink will often be a little lighter in colour if there’s an opacity issue with the ink. With a white underbase, this makes the ink appear to be a tint. Getting more ink down onto the shirt can solve this usually. Try a softer squeegee or double stroking the colour.

6. If changing your underbase won’t affect other colours in the print run, consider switching from a white to a grey or another colour that won’t influence the problem colour as much.

7. If you mix your own colours, or have access to ink additives, sometimes using a high opacity base or a similar product can help the situation. Talk to your ink rep and have them educate you on the line up they offer.

8. Don’t be fooled by any influence that the surrounding fabric of the shirt can play on how a colour appears. Sometimes you might try folding the shirt so the shirt fabric isn’t visible and you are only looking at the printed colour next to the Pantone book. This is a good double check when the shirt colour is really bold, or if you are an old guy like me that has to wear glasses now.

9. Screens matter. If it looks like you need a new one, pull that trigger early. It’s going to take some time to come out of the screen room, get set back up and registered.

10. If you start doctoring up an ink bucket beware. It is extremely easy to start adding pigments or white or black to ‘make’ the colour right. Sometimes this works, sometimes it doesn’t. If you are going this route add very small amounts at a time and completely mix the bucket. Make sure you relabel the bucket too, as a precaution for the next job. Also know that the more you screw around with this, the less likely you will ever be to replicate the ink a year from now on a reorder if you run out.

11. When all else fails, contact your ink manufacturer and let them know what’s going on. They sometimes can help with a suggestion or new formula.

12. Stay calm. Usually these problems happen when something is due, the client is standing there during a press check, it’s critical client or some other intense problem. There are a lot of variables that can throw off the final printed colour match, and a good number of them don’t come from the ink bucket. Think it through and don’t be afraid to ask for help if you need it.