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Convert from RGB to CMYK Online

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Convert RGB to CMYK and Reduce Colour Issues When Printing



Have you ever tried to print an image, and while it looked fantastic on your computer screen, on paper the colours were off?  I have, and it was really disappointing and frustrating.  When this happens to an image, you need to convert from RGB to CMYK online.  Let me explain…


Computers and printers speak different colour “languages”.  When computers make colours, they choose from Red, Green and Blue (aka RGB).  Printers have to make their colours from CMYK: Cyan, Magenta, Yellow and “Key” (Black) inks.


By using the RGB scheme, computers can make way more colours than printers can.  This means that sometimes the image you see on your computer screen has colours your printer actually can’t print.


For example, this is how my Antlers/Flowers printable looked the first time I tried to print it out (*my printer is acting up, so this is a recreation of what the RGB printout looked like).


Printable Antlers Flowers.

The original RGB image display on a computer screen. (PNG)

Antler Flowers Off Colours

What the same RGB image looked like printed out (simulation).










To keep the colours in a printed image as close as possible to those on a computer screen, you need to let the printer receive the image in a language it can follow.  This is done by changing the image from RGB to CMYK before printing.   I know it sounds complicated, but it’s really not.


Changing the colour language doesn’t 100% fix all colour differences, but it makes them a whole lot better.  I’ve noticed that PDFs changed to CMYK tend to print a lot closer to the original colour than JPGs and PNGs in CMYK do.  Either way, changing the image to CMYK will let you see what it will look like printed out, and give you a chance to change your mind before wasting printer ink and paper.


You can easily convert an image from RGB to CMYK (a TIF file) using a really easy, free online converter tool.  The one I prefer for JPG and PNG files is  Converting PDF to CMYK will be explained further down.



JPG vs PNG vs PDF?!

It’s totally normal to get confused by these!  In a super basic explanation, these are just three different ways to save stuff on computers.


JPG file: Recommended for images that will be used online.  Because JPG images have lower quality, they take up less space and don’t slow websites down.  No one notices the quality loss because online images are pretty small.


PNG file: Recommended for images that will be printed.  PNG images are higher quality, so they keep their detail and crispness when enlarged for printing.  This higher quality also means they take up more space, and can slow websites down when used online.


PDF file: Recommended for text documents, newsletters, forms, etc.  Once saved as a PDF, a document cannot be edited.  This means the  formatting doesn’t get messed up when it’s opened on different computers, cellphones, tablets, etc., so everyone sees it the exact same way.



Convert from RGB to CMYK Online for PNG and JPG

1. If your image is a PNG or JPG, go to


a. Click on “Choose File”.  Choose the image file you want changed to a CMYK.


b. Next go to the bottom of the screen, click the blue “Start” button.  When it’s done, just click on the blue link to download your CMYK image (my link said Printable_Antlers_Flowers_cmyk.tif).


Convert from RGB to CMYK Online

















c. Look at the two Antler/Flower images below. The one on the left shows what the original looked like on my computer screen (RGB).   The image on the right shows what my image now looks like printed out on paper (CYMK).  It’s a huge improvement over the faded, off colour printed image above!  The new image has a small colour difference still, but it’s pretty close to the original.

(FYI This image is a printable from my Free Resource Library.  For access, sign up for my newsletter at the top or side of any post and a password will be emailed to you.)


Convert from RGB to CMYK Online Color Difference

















Sometimes there is still a noticeable colour difference, even after the image is changed to CMYK.  I used my “Ho Ho Ho” printable as example where the colours were not quite as close (it’s also from my Free Resource Library).  Again, this seems to happen more with PNG and JPG images than with PDFs.


Convert from RGB to CMYK Online. This image shows a red PNG picture that has been changed to RGB form and the same red PNG picture in CMYK form. The red in the CMYK image is much darker than the RGB red.


















Even though the converted “Ho Ho Ho” image’s colours are really close, the CMYK image is a lot darker than the original (RGB).  Depending on your intended use this might be fine, or it might make the image unusable for you.


As you’ll see below, the colours in this image were much closer when I used a PDF file (I used a PNG file above).



Convert from RGB to CMYK Online for PDF

As doesn’t work with PDFs, we need to use another program to convert PDF to CMYK colour code.  Don’t worry though, because this free online program is also incredibly easy to use!!


a.  Go to (it’s a sister site to the one we used above).


b.  Click on “Choose File”.  This will let you get your PDF from your computer.


c.  Go to the bottom of the page and click “Start”.  Your converted PDF will be ready in a moment.



Convert from RGB to CMYK Online. Changing PDF from RGB to CMYK Colour.















d.  The result page is shown below (with PDFs a comparison of the before and after images is NOT given).  Click on the blue link to download your CMYK image (my link said Download Printable_Ho_Ho_Ho_Santa_PNG_PDF_cmyk.pdf)


Convert from RGB to CMYK Online. PDF RGB to CMYK Results.















I wanted to see the old and new PDFs side by side to compare colours, so I put them in a Canva design for comparison:


Convert from RGB to CMYK Online Colour Comparison. This time a PDF file of the red Santa image was used for the conversion. The RGB and CMYK images are now very similar in colour.














As you can see, while there is a tiny difference, these images are pretty darn close.  I decided to check the colour codes to see just how close. It turns out that their codes are a teeny bit different, but so similar that they both fall into the same colour category (Crimson).


RGB = hex colour code: d42426 Crimson

CMYK = hex colour code: d72328 Crimson


As I mentioned before, PDFs often have very close colours when changed from RGB to CMYK (much closer than PNGs and JPGs).  I’m not sure why, but I’ll update this post when I find out.  The good news is, it’s easy to change PNG and JPG images to PDFs…and that post will be coming soon!


Sometimes when printing online images, the colours are off or faded. To solve (or at least reduce) this problem take the image and convert from RGB to CMYK online.  If you decide to give this a try with an image, check back in to let me know how it turned out.



If You Enjoyed this Article, Have a Look at These Related Posts:


How to Print Quality Printables



How to Print Quality Printables






How to Resize an Image



How to Resize an Image






How to Convert a PDF to JPG



How to Convert PDF to JPG





Stephanie  🙂


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