Printing & Color

Why You Need to Know a Few Things About Colour Before You Hit “Order”

When you order a product from an online printshop, here’s something many people don’t realise: Your file usually isn’t checked for colour quality.

Most online printshops run your file through an automated preflight check, but this only catches the most basic and critical mistakes — like if your file size doesn’t match the product format, or if your resolution is too low for print.

What it won’t catch is whether your colours are too dark, overly saturated, or accidentally left in RGB mode. And no, there usually isn’t a human reviewing your file — unless you specifically pay for a premium file check (and even then, colour isn’t always part of the check).

👉 That’s one reason online printing is so affordable. It’s fast, automated, and cost-effective. But it also means you’re expected to know a few basics.

This article covers one of the most important ones: Colour. We’ll explore what happens when your vibrant screen design becomes a dull print, what CMYK actually is, and how to get your colours looking right before you press “send.”

Understanding Colour in Printing: Why Your Print Doesn’t Look Like Your Screen

Have you ever uploaded a beautiful photo of your painting — only to receive a printed canvas that looks oddly dull, too dark, or just… off?

You’re not alone. It’s one of the most common surprises in online printing — and one of the easiest to fix once you understand how colour really works in print.

When the Print Doesn’t Match the Painting

I once worked with a customer who was a gifted painter. She wanted to turn her oil-on-canvas works into postcards — a lovely idea and a popular way for artists to share their work. But while she knew how to get colour onto canvas, she didn’t know how to get it off the canvas and onto print.

The biggest issue? Lighting. When photographing paintings, most people use too little light. Her colours looked dull and flat in the photo — not at all like the vivid original. It wasn’t the camera’s fault; modern cameras are surprisingly capable. It was simply a lighting problem.

Once the painting is photographed, there's still more to do. You need to:

1. Photograph the painting under strong, indirect lighting. (Use more light than you think!) Avoid shadows and reflections.
2. Edit the photo in an image program like GIMP:
   • Convert the image from RGB to CMYK
   • Adjust contrast, saturation, and colour balance
   • Crop it to the correct dimensions
   • Save it as TIFF or PNG to avoid compression loss
3. Create the print file using layout software like Scribus. Place your image on the correct product format (e.g., postcard) and export a print-ready PDF.

Many artists skip this last step and just upload a JPG — that’s when I used to step in and cancel the order (if I caught it in time). Even if you use an online design tool like print24.fi, you still need to do steps 1 and 2 yourself or get some help!

I'll write a full guide on From Painting to Postcard soon. But for now, this overview should help you avoid the most common mistakes — and make sure your artwork prints as beautifully as it deserves.

Screens vs. Paper: Two Very Different Worlds

• Screens use RGB (Red, Green, Blue) and emit light
• Print uses CMYK (Cyan, Magenta, Yellow, Key/Black) and reflects light

RGB can show more colours than CMYK. That’s why a print might look “flatter” — it’s a narrower colour space.

Tip: If your design is in RGB and gets converted to CMYK at the printer, colours may shift — especially bright greens, blues, and neon tones.

What About Photos?

Photos are always in RGB when taken on your camera or phone. When printing them:

• Convert to CMYK using image editing software (like Photoshop or GIMP).
• Be prepared for slight colour shifts — especially in greens and blues.
• Increase contrast slightly before printing — printed photos often look darker.

Quick Tip: If you're unsure how it will look, do a small test print first (even on your home printer in greyscale, just to check exposure and balance).

What is CMYK — and Why Should You Care?

CMYK stands for the four basic ink colours used in most professional printing:

• Cyan (bright blue)
• Magenta (red-pink)
• Yellow
• Key (Black)

These four inks are mixed in varying percentages to produce the full spectrum of printable colours — just like mixing paint. Most home printers use the same system, only on a smaller scale.

CMYK is the standard for a reason

When you order from an online printshop, your file is typically printed on huge industrial digital presses — think of them as ultra-precise, truck-sized versions of your office printer. These machines are fast, consistent, and calibrated to work within the CMYK colour space.
Some high-end presses can also print special colours like gold, silver, or neon inks. But that’s the exception, not the rule. Most of the time, your file will be converted to CMYK — even if you uploaded it in RGB. That’s when colour surprises happen.

Try printing bright turquoise or neon purple: in RGB it glows, in CMYK it dulls — unless carefully adjusted.

The artisan alternative

Now, let’s say you take your design to a local print artisan — someone who still works with letterpress, screen printing, or risography. That printer might mix inks by hand, creating rich, deeply saturated colours that aren’t even possible in CMYK.
For example, a letterpress printer can mix a specific Pantone colour just for you, creating results with far more depth and texture than any digital press could replicate.
But… that takes time, skill, and money. And it’s not ideal for large runs or tight deadlines.

RGB vs CMYK vs Pantone — What’s the Difference?

Example: Neon orange? CMYK struggles. Pantone nails it — if your printer supports it.
Painomestari tip: For logos or brand colours, Pantone is ideal. For everything else, CMYK is usually enough.

Why Black is Not Black is Not Black

In professional printing, "black" isn’t always just black. Here’s why:

Standard Black (also known as "flat black")

• CMYK value: 0, 0, 0, 100
• What's happening: Only the black (K) ink is used.
• Result: A deep grayish black that looks fine in small text or line art, but can appear a bit dull or uneven in large solid areas.

This is the default black used in most documents — and it’s good for text because it avoids misregistration (where color layers don’t align perfectly).

Rich Black

• CMYK value: Typically something like 60, 40, 40, 100 (can vary)
• What's happening: A combination of all four inks to create a fuller, deeper black.
• Result: A darker, more vibrant black — perfect for large areas like backgrounds or bold design elements.

Cool Black (Cold Black)

• CMYK value: e.g. 100, 0, 0, 100
• What's happening: Cyan is added to black, giving the tone a blueish undertone.
• Result: A slick, modern black often used in corporate branding or when you want a colder, cleaner look.

There’s also Warm Black (adding more magenta or yellow) if you want a softer or brownish tint.

When to Use What?

Paper Matters Too: How Matte vs. Glossy Paper Affects Colour

Once you’ve chosen your colours and prepared your print file, there’s one more choice that dramatically affects how your print will look and feel: the paper finish. Specifically — matte or glossy.

Let’s break it down:

Glossy Finish

• Shiny, reflective surface
• Colours appear more vibrant, richer, and with greater contrast
• Especially effective for photos, product images, and high-impact graphics

Pros:

• Makes colours “pop”
• Great for marketing materials, postcards, and product packaging
• Adds a premium sheen

Cons:

• Can cause glare under lighting
• Fingerprints may show
• Not great for writing on

Matte Finish

• Smooth but non-reflective surface
• Colours appear softer, more subdued, and often a bit warmer
• Better suited for text-heavy materials, artistic layouts, and muted designs

Pros:

• No glare — easier to read in all lighting
• Feels elegant and understated
• Writable with pens and pencils

Cons:

• Colours may look duller compared to screen
• Blacks might look less deep

Same Colour, Different Look

The exact same design will look noticeably different on matte vs. glossy paper — even with identical CMYK values.

A glossy finish will amplify saturation and contrast. A matte finish will absorb light, making everything feel softer, more refined — sometimes even nostalgic.

When to Choose Which?

A Word on Style Guides – And Why They Matter

Not all colour confusion comes from RGB vs. CMYK. Sometimes, it starts before you even open your design software — with the question: What colours am I supposed to use?

Let me share a little story.

I was once designing a flyer for a local party ahead of the municipal elections.
Like many organisations, they had a logo and some older versions of a flyer, but when I asked for the colour specifications, I got raised eyebrows.
But here’s the thing — most clubs, political parties, and medium-sized businesses actually have something called a style guide (or at least, they should).
So I dug around in the press section of the party‘s main website and sure enough there was the style guide.
All the colors nicely defined for print.

A style guide is a document — sometimes a single page, sometimes a small book — that defines:

• the logo and how to use it,
• the exact colours (usually in CMYK or Pantone),
• the fonts and typography rules,
• and the general layout guidelines for various materials like flyers, websites, business cards, and more.

These guides are usually created by the agency that designed the logo in the first place, but often get forgotten or buried over time.

Tip: If you’re creating print material for a club, party, or business, ask if there’s a style guide — even an old PDF lying around. It can save you hours of guessing.

But I Don’t Have a Style Guide… What Now?

That’s completely fine — most small organisations don’t.

If you’re working from scratch, here’s how to build your own ad hoc colour palette:

• Start with your logo. If you already have one, use a free colour picker tool (like Adobe Color or Photopea) to extract the main colours.
• Or use a photo. Choose an image that captures the mood or purpose of your print product — nature, people, products, a landscape — and extract a colour palette from that.
• Refine for print. Once you have your colours, convert them into CMYK and adjust them slightly to suit the paper and mood. Bright RGB tones might need to be softened or shifted.

Personally, I like to use the Adobe Color Wheel to build harmonious palettes. Then I import them into Scribus, the free open-source layout software I use. (Yes, a beginner-friendly guide for Scribus is on the way!)

You don’t need to become a colour theory expert — just aim for:

• Consistency
• Legibility
• Mood alignment

The One-Page Checklist for Colour Success

• Start in CMYK
• Avoid bright RGB colours
• Convert and adjust photos
• Choose your paper wisely
• Test print if unsure
• Ask Painomestari for help

Final Words from Painomestari

Colour is tricky, but once you get the hang of it, your prints will suddenly click. You’ll stop being surprised, and start being proud of what arrives in the post.
And hey — if you're ever unsure, just send me a message. I’ve made all the mistakes already so you don’t have to.