Saturday, 17 May 2014

Graphic Design Basics: Colours, pt. 2: Rich Black

In part 1.5, we settled for CMYK over RGB, as far as designing is concerned. And one the most important differences between the two is their default black.

RGB black is nice, deep and... well, black. CMYK's default black is dull and... grey. Why so? Because it uses only one ink, which may look well while you are designing (depending on the options), but when you export the file or, God forbid, print CMYK black, it shows its true grey nature.

Here's what I am talking about:

Represented with digits, it looks like this:

Rich Black

R: 0, G: 0, B: 0. It's simple. You block all light and you are left with the fathomless, ghastly black of the void.

Poor Black

C: 0, M: 0, Y: 0, K: 100. Print simple black ink on a white base and you get meh black.

Truth be told, no black would look super black when printed on a t-shirt with a Direct-To-Garment printer, as illustrated by this RedBubble graphic, but still, rich black would look better than poor black.

So what's the trick, then?

Well, working in CMYK doesn't stop you from having rich black. The default black in the swatch is C: 0, M: 0, Y: 0, K: 100, but all you need to do is change the colour of your shape or path to:

C: 75%, M: 68%, Y: 67%, K: 90%

This is the CMYK equivalent of RGB black. Of course, it means it will use colour ink, as well as black ink, to achieve that deep look, but you shouldn't be cheap on the inks if you are printing a t-shirt. :)

NB! If you are using Adobe Illustrator, the default CMYK black would be displayed as regular, rich black on screen. To avoid confusion, set the on screen option to "Display All Blacks Accurately". This is found in Edit -> Preferences -> Appearance of Black.

NB 2! If you are printing from a .png file, I have noticed that Illustrator doesn't export rich black properly when you use the "export" option to create the .png. You don't get true rich black, but sliightly greyer black.

There's an option "Output All Blacks as Rich Black", but the funny thing is that it only works on default CMYK black, not on all blacks as it claims.

Here is what I mean:

The difference is not that big, but I still prefer my files to use true rich black. The only workaround I found is to save the file as .eps, open it with Photoshop, change the colour space to RGB and save as .png.
It takes a bit of extra time, but at least I can sleep soundly in the knowledge that my black is proper all the way. :D

That's it for now, stay tuned for more graphic design tips.

Also check out part 1 and part 1.5.

Friday, 2 May 2014

Graphic Design Basics: Colours (Pt. 1.5)

So, after everything we've discussed in the first part, there is still one big question left unanswered.

Should I design in CMYK or RGB and which colour space should the final output file be saved in?

During the designing process, I always work in CMYK. It excludes any unprintable colours from the palette and gives me a better idea about how the final product would look.

I've read some people saying that their printers actually have a greater gamut than CMYK SWOP (Adobe's default CMYK space), so they use RGB and while there will be some colour loss when comparing the final product to the RGB file, it still gives them a greater colour range. I don't know much about the various printers' capabilities, so I won't call bullshit on that one, but the CMYK SWOP space is big enough for me in any case, so I stick to CMYK, and I suggest you do too. (If you had a super-duper printer with a wiiide colour gamut, you probably wouldn't be reading this blog entry anyway.)

Next, you need to know what method would be used when printing the t-shirt. If you are doing the printing yourself, you should already know. If not, simply ask the people from the printing service or consult the FAQ of your chosen online retailer. The options are basically two:

1. DTG (Direct To Garment, or simply digital printing). In this case, you should save your final file in RGB. Inkjet printers would automatically convert the colour space to RGB, but you don't want to trust a printer with that, so it's best to save the file in RGB by yourself.
In addition, the best format to save in (unless the printing service accepts vector files) is png (it is lossless, supports transparency and doesn't take up much space), and png doesn't support CMYK, so you will be forced to save in RGB anyway.

2. Screen printing. With screen printing, you should not only use CMYK, but probably spot colours, if the press is manual. With automatic presses four colour printing is OK too. In addition, screen printing would require image preparation, which can be done by you (maybe I'll do a blog entry about colour separation in the future), or by the printing service. Again, you should ask them for guidelines.

Coming up: Graphic Design Basics: Colours Pt. 2 - Rich/True Black vs Default CMYK Black.