CMYK or RGB For Printing Posters?


Which color model should you use for printing a poster?

The choice comes down to how many copies of your poster you plan on making.

If you are only going to make one copy, use RGB because it’s easier than trying to convert from CMYK colorspace back into RGB colorspace later on. But if you know that you will be making multiple copies, it’s better to use CMYK because it uses less ink and has a better color gamut than RGB.

In this article, you will learn how to make a high-quality poster in either color space.

So stay with us and keep reading!

What’s The Difference Between CMYK and RGB?

Printing usually uses ink to create color, though dyes or paints are pretty common as well.

  • CMYK refers to the four-color process in which cyan, magenta, yellow, and key (black) ink are applied in different proportions to produce a full-color image on paper. The CMYK color model is often used because it’s less expensive than the eight inks required to produce full-color using RGB models.
  • RGB corresponds to red, green, and blue, also named primary ‘additive’ colors. This provides a more vivid spectrum of color and allows for easier blending than with ink or paint. You will generally use RGB for more natural colors, like art and photographs, whereas you will use CMYK for long-lasting black text and images.

Even if most of the world has fully adopted color printing, some people still prefer to read the text in black. The biggest challenge is that each typeface, including serif and sans-serif fonts, has distinct lightness values for each letter, resulting in specific color printings.

Which one should you use?

If printing text, black is always best for readability. If you are designing images and artwork that has no text, then RGB would be best.

How to Print Posters in CMYK

The most cost-effective way is using the four-color process. The other option is spot colors, which are usually used for high-value graphics or small areas of text that need special attention.

To print a poster in CMYK mode:

1) Open Photoshop and choose File > New

2) Click on the “settings” icon at the bottom right of the new document tab (it looks like a screw).

3) Under “Color Mode,” select CMYK Color.

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4) You can change the size and resolution to your liking, but be sure that the pixel count is a multiple of 600. So, for a 30″ X 40″ poster at 150 PPI, the pixel dimensions should be 5400 X 7200.

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5) Click OK, and you’ll have a CMYK-colored blank canvas.

6) Now, add an adjustment layer for the desired color aesthetics (lightness, contrast, color balance, etc.).

7) Merge all layers onto one new layer.

8) Choose File > Save As

9) Change the file type to Photoshop PDF(*.pdf).

10) Change the Colors setting to CMYK Color, and click Save.

Now you’re ready to print your poster!

Can You Print Posters in RGB?

If your design includes photos with saturated hues or gradients, it’s best to set up your document as an RGB file. In this way, you can include all the possible color combinations.

So far, adding color mixing was only possible in self-lit systems such as LED displays. But years ago, a German company named “Merck” developed highly reflective pigments called Spectraval, which aimed to create white color by blending red, green, and blue tones.

In 2013, the artist Lorenz Boegli printed on a black substrate these three colors adding Spectraval and came out with the magic result: these pearlescent pigments generated white!

The RGB print was finally made possible!

Through Spectraval, RGB printing can fit plenty of traditional systems, including gravure, flexo, and screen techniques.

The result is an “additive” printing system, in which each of the three colors (red, green, and blue), blended, creates a white result (layer after layer) starting from a black background where Spectraval pigments are printed on.

For more details, please visit Merck’s official page!

This new process is the opposite of CMYK printing, also defined as “subtractive”. In this case, starting from a white substrate, the black comes up by progressively subtracting each color.

The application of RGB printing with Spectraval goes from packaging, covers, and, most of all, wallpapers!

That’s why we can affirm that it’s possible to print posters with RGB!

However, you have to be sure that your printer supports RGB mode first.

Is There A RGB Printer?

We have done countless researches on the web and we discovered a top-notch printer that used RGB digital print: LumeJet S200!

We use the past tense because LumeJet Print Technologies company entered liquidation in 2018.

But it’s still possible to find some used machines at a good price on the web!

Anyway, this printer recognizes the JPEG format, so there’s no need to convert RGB to CMYK, as usually happens.

By applying light-sensitive paper, LumeJet200 doesn’t use ink at all but a DPH (Digital Print Head) with three RGB colors.

The resolution of the images is accurate, up to 4000dpi, and matches the sensitive paper’s one. Also, as we said before, RGB offers broader tones than CMYK, allowing better visual quality overall.

Compared to conventional models, LumeJet provides a 40% greater color gamut - around 550,000 colors! 

Through the LumeJet website, you could customize and order prints and wallpapers. On average, the cost of an 8×4 print was around $ 6,50.

How to Print Posters At Home? (Step-By-Step)

Printing posters at home is a great solution to avoid extra expenses and time-wasting. But before starting, make sure to have the necessary equipment!

In order:

  • Razorblade (recommended) or Scissors
  • Ruler
  • Tape (the clearest type)
  • Hanging Putty
  • Posterboard
  • Double-Sided Tape
The technique shown is called "Rasterbate" and describes the process of creating a full-size poster by assembling several smaller sections of an image.

To get started, you need to find an image to print. This image should have clear and contrasting colors (e.g. black & white) to achieve the best result once printed.

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Another great example is this picture. We’ll be using it for the next steps.

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As you can see, there are plenty of darks and lights and a mix of contrasting colors.

At this point, you should consider where you want to hang this poster. If you want to attach it to the wall, measure the area and write down the dimensions.

Also, measure the dimension of the printer’s paper and take notes.

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From the website:, download the “Rasterbator Standalone 1.21” software and install it on your computer.

Open it, and upload the source image as required.

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Then, you have to select the paper size. Dare to choose the correct size based on the previous measurement.

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Now, the software asks you to define the output size. You will need to make few attempts before getting the desired result.

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In the next screen, leave the option “Draw cutout line” flagged, making it easier to cut away the white areas between sections of the photo.

For the “Dot size”, we selected 3mm. If your poster is way larger, you can shift up but not overcome the 10mm size.

Then choose your preferred “Color mode”.

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Lastly, save it as a PDF file and click the “Rasterbate!” button.

When it’s done, open the file and print it.

Make sure to print all the pages, “Actual” size, and the same orientation as before (Portrait/Landscape).

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The pages will be printed in a specific order to be easier for you to assemble them.

Once printed, laid them on a flat surface, in the same order.

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At this point, we need to trim out the white borders on each page.

So let’s bring our ruler and a rigid surface (as a canvas) to place behind the paper. The ruler has to adhere to the dotted line on the paper.

With the razor, we start to cut gently along the ruler without rushing.

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Repeat this operation for each page.

Once finished, we need to tape all the papers together. Pick the first two images (in column order), flip them over, and align the edges.

Put the ruler over them to keep them locked and secure them with tape.

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Keep securing all the edges and move on to the next two papers, following the same order.

Once we have all columns secured, we need to tape them together.

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Use the same method as before: put a ruler over them and secure the edges with a piece of tape.

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Now, it’s time to hang our poster!

Bring the Posterboard and place the poster on top of it.

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Centers it and with a pencil make markets on each corner.

With the double-sided tape, draw a line from one corner to the other. Then another line about five inches far, and keep going with the third one.

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Now stick the left side of your poster to the first line and press with the ruler from left to right carefully until the second and the third line.

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RepeaRepeat the operation, add more and more double-sided tape lines and keep pressing with the ruler until the end.

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Finally, the only step left is hanging!

We recommend using a good amount of hanging putty and split it into four pieces.

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Take the putty and start kneading it until it’s soft. Then, divide it into four pieces and place it on each corner of your poster board.

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After that, press firmly against the wall which you want to hang it on.

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And that’s it!

Here’s your homemade poster printed on ordinary paper!

For a complete recap of all the steps, we recommend watching the video below!

How to Print Posters Online?

Maybe you think it’s too fatiguing to make and print a poster on your own.

So why don’t you try an online service?

Every day more and more people are turning to online print shops because of their advantages: they’re fast, easy, and you can order any photo products that will fit your style and budget.

Using sites like those presented below, you can find many interesting models, sizes, and price options.

Three popular online services to create photo/poster prints are:

  • Canvas Champ – It provides high-quality canvas wraps, stretched and gallery-wrapped canvases, vinyl wall decals, and more at affordable prices. Such products as rolled or gallery-wrapped canvases are a great way to add life and colour to your space. In addition, these canvases make an excellent gift for any occasion, and you can personalize it by adding text or photos.
  • The next service is Canvas Pop, where you can choose among many different sizes of canvases (from 8×10 inches to 40×60 inches) and effects (from matte to glossy finish). You can upload your desired image in the design tab, choose a template, or start from scratch. It’s also possible to add text, clipart, and other graphics.
  • The last service we’ve chosen is Printicular, where you can either choose a photo on the site or upload one from Facebook, Instagram, or your computer. There’s also a size chart, so you’ll know how large to make the picture. You can add a variety of effects and simply press ‘Print’ when you’re ready!


We have seen so far different techniques for printing a poster: first of all, CMYK and RGB. For more practical users, we recommend the ‘homemade’ procedure. It’s not difficult at all, but it takes more time and patience.

Furthermore, we have mentioned three quality online services (for’ lazier’ people!) like Canvas Champ, Canvas Pop, and Printicular. Of course, there are way more, but we have already tried them and we had a positive experience overall.

Now it’s upon you!

Which of the printing methods are you going to use for your favourite poster?

Comment below or write us on the contact page. We can’t wait for your feedback!


Print On Demand World Staff

Hey Everyone! We hope you enjoyed reading the article and the information provided on it. If so, share it through your socials and keep visiting our blog, discovering the wonderful World of Print On Demand! Arrivederci! :)

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