When displayed on screen, K100 appear as the normal black we would expect to see.
But during printing output, the K100 result is actually more greyish to our eyes.
Now that's a problem for this artwork below:
While it appears OK on screen, the printout is actually not OK, as the color texts are much much less contrast to the greyish output K100, which make them almost unreadable.
You may solve the K100 colour by selecting "preserve pure black" in the colour settings.
I don't think that will necessarily solve the contrast between black and deep colours though. I've seen so many publications from people that have done it, but such a combination works only on screen or in a backlit poster. Paper just isn't bright enough on its own to provide contrast between a dense colour and black. But you'll probably find if you put your print on a lightbox, it works fine.
My rule of thumb is that to ensure optimum legibility of text against black, you should use only white, yellow or a 30% tint of any other colour.
Hi Harry,
In my Color Management -> Default Settings, "Preserve pure black " is checked.
While I understand that K100 would be printed as greyish black on paper, I'm wondering is there a way to display it "correctly" so that the designer could avoid using the wrong color?
Here in Malaysia, all outdoor billboards and banners are printed on tarpaulin with 4-color or 6-color. The output does not have the contrast issue between the black and dark colors. I tried to explain to the client regarding the difference between the materials (paper vs tarpaulin), but to them, what appears OK on tarpaulin shall also appear OK on paper.
So, I think if the screen can display the K100 accordingly as on paper, then there shall not be any argument between paper and non-paper material.
The CMYK 100% black is showed an printed correctly, as must be. It's a transparent ink, so it's not the same of 100% Pantone Process Black, wich is opaque. Almost nobody print CMYK 100% pure black for a background (it's usefuil for small text and lines), if it's for offset printing, usually we add 40%/50% cyan. And, if it's for plotter (backlight, banners, etc) you must use at least 40/50% of the other 3 inks. You can see the difference on the screen, also if you compare pure black with "rich" black (of course 100% of all inks is too high for printing)
Hi Ariel,
Thanks for your reply.
So I think if we use C50 K100 instead of K100 for an intended black background, then the offset printing result (contrast between dark colors and black) would be close to what we see on screen? Instead of a greyish black?
I'll try that next time. Like what you suggest, I rarely use K100 for full background color. The artwork for this job was provided by client.