3 posts on CMYK

100% Cyan in CMYK is NOT rgb(0,255,255)!!

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As I mentioned in an earlier post of mine, I have to create a color picker, so I’ve already started to write the code for the Color class it’s going to use. I need it to natively support RGB, HSL, Lab and CMYK. And the latter part is causing unexpected trouble.

It seems that there is the notion out there that conversion from CMYK to RGB is easy. Newsflash: It’s not. As every graphic designer knows, the CMYK color gamut is smaller than the the RGB color gamut (even the sRGB color gamut). You can’t take a CMYK color and convert it to an out-of-CMYK-gamut RGB color! That’s nonsense! And it’s precisely what most conversion algorithms and color pickers out there do! Even Adobe Kuler!!! Since yesterday, I’ve studied dozens of algorithms and color pickers that claim to do CMYK -> RGB conversion, and every single one of them is wrong.

You can test a color picker that claims to support CMYK, or a CMYK <–> RGB conversion algorithm in the following simple way: Test how it converts the color CMYK(100%, 0, 0, 0) to RGB. If the result is rgb(0,255,255) then the algorithm is crap. rgb(0, 255, 255) is neither the same color, nor is it even in the CMYK color gamut! So basically, these algorithms convert a CMYK color to an RGB color that is outside of the CMYK color gamut! A color that cannot be represented with CMYK is supposed to be the result of a CMYK->RGB conversion? This is madness!

So far the only CMYK -> RGB converter that I’ve seen and does it right, is the one used by Adobe CS products (Photoshop, Illustrator, etc). And that makes me wonder why Kuler does it the wrong way, since they have already figured the algorithm! It’s crazy!

What’s even more strange is that I can’t even find which sRGB colors are usually out of the CMYK color gamut, so that I can adjust the algorithm I use properly (even if it just clipped the color to the nearest in-gamut one, it would be an improvement). I’ve been searching since yesterady even for that with no luck. I hope I don’t end up using the wrong algorithm myself too…

CSS3 colors, today (MediaCampAthens session)

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Yesterday, I had a session at MediaCampAthens (a BarCamp-style event), regarding CSS3 colors. If you’ve followed my earlier posts tagged with “colors”, my presentation was mostly a sum-up of these.

It was my first presentation ever, actually, the first time I talked to an audience for more than 1 minute :P . This caused some goofs:

  • When introducing myself, I said completely different things than I intended to and ended up sounding like an arrogant moron :P
  • I tried not to look at the audience too much, in order to avoid sounding nervous, and this caused me to completely ignore 2 questions (as I found out afterwards)! How embarrasing!
  • At a certain point, I said “URL” instead of “domain” :P

Also, I had prepared some screenshots (you’ll see them in the ppt) and the projector completely screwed them up, as it showed any dark color as black.

Apart from those, I think it went very well, I received lots of positive feedback about it and the audience was paying attention, so I guess they found it interesting (something that I didn’t expect :P ).

Here is the presentation:

Please note that Slideshare messed up slide #8 and the background seems semi-transparent grey instead of semi-transparent white.

By the way, I also thought afterwards that I had made a mistake: -ms-filter is not required if we combine the gradient filter with Data URIs, since IE8 supports Data URIs (for images at least). Oops, I hate making mistakes that I can’t correct.

Here are some photos from my session. If I did it correctly, every facebook user can see them. If I messed things up, tell me :P

News, Personal, CMYK, Colors, CSS, CSS Values, Feature Detection, Hsla, JS, PHP, RGBA, Speaking
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CMYK colors in CSS: Useful or useless?

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As someone who dealed a bit with print design in the past, I consider CMYK colors the easiest color system for humen to understand and manipulate. It’s very similar to what we used as children, when mixing watercolors for our drawings. It makes perfect sense, more than HSL and definately more than RGB. I understand that most of us are so accustomed to using RGB that can’t realise that, but try to think for a moment: Which color system would make more sense to you if you had no idea and no experience at all with any of them?

Personally, even though I have lots more experience with RGB, given the fact that most of my work will be displayed on screen and not printed on paper, when I think of a color I want, I can instantly find out the percentages of Cyan, Magenta, Yellow and blacK needed to create it. I can’t do that with HSL or RGB, I’d have to play a little bit with the color picker’s sliders. I sometimes start by specifying a color in CMYK and then tweaking it via RGB or HSL to achieve the exact color I need (since the CMYK gamut is smaller than the RGB gamut) and I find that much faster than starting with RGB or HSL right away.

Also, when you don’t have a color picker, it’s much easier to create beautiful colors with CMYK than it is with RGB. For example the CMYK magenta (0% Cyan, 100% Magenta, 0% Yellow, 0% blacK) is a much better color than the RGB Magenta (255 Red, 0 Green, 100% Blue).

Given the above, I’ve always thought how much I wanted to be able to specify CMYK colors in my CSS. I agree that sometimes this would result in crippling myself, since as I said above the CMYK gamut is smaller, but it has other significant advantages that I think it would make it a useful option for some people. There are algorithms available for CMYK to RGB conversion, and the browser could use those to display the specified color on the screen. Then, if the user decided to print the page, The CMYK colors could be used as-is for the printer. Another advantage, as none of the current CSS color formats allow us to control that. People who don’t find the CMYK color system easier for them to understand, they could still use it for their print stylesheets.

Also, graphic designers who decided to switch to web design would find it much easier to specify color values in a format they are already comfortable with.

To sum it up, the advantages that I think this option would provide us are:

  1. A color system that’s easier for most people to understand and manipulate.
  2. The colors you get when combining “easy” CMYK values (0%, 50%, 100%) are more beatuful than the ones you get with “easy” RGB values (0, 128, 255). Bored people and people without a taste in color selection would create more beatuful websites this way and our eyes wouldn’t hurt.
  3. We would be able to specify how our colors will get printed, something that is not currently possible at all. Extremely useful for print stylesheets.
  4. It would be easier for graphic designers to switch to web design.

And the format is very easy to imagine:

background-color: cmyk(0, 100, 50, 0);


background-color: cmyk(0%, 100%, 50%, 0%);


background-color: cmyk(0, 1, 0.5, 0);

So, what do you think? Useful or useless?

Edit: As it turns out, I’m not crazy! The W3 already considers this for CSS3 with the 3rd format (from 0 to 1)! However, no browser supports it yet, not even Webkit nightlies… :(