Rich Black Vs 100% K
tsmalldon (45 points) | Tue, 2007-02-13 18:45Hi All,
Quick Question. I've submitted literally thousands of pieces to press thus far in my career and never experienced an issue such as this.
Printer calls me up today and says I need to switch all my blacks (In the photoshop document) too 100% K. I was a little mystified because it was my understanding that there are different types of black
Cool black, velvet black, rich black......depending on the color combination used.
Any idea why the printer would suggest this? They didn't elaborate.
Trevor
Trevor Smalldon
Graphic Artist
Is this a different type of document or is it a new printer etc?
I had a similar weird issue last weekend where they rejected a 2 colour print job with a spot channel and demanded I do it in CMYK with the gold spot as yellow.
All very strange and a sign of a poor printer IMHO.
Of course this depends entirely on what the artwork is, if it's very text heavy then I'd agree that is maybe should be 100% K, but that's down to preference and certainly no reason to reject the artwork.
Odd.
The more you work with your printer the better your experience will be. ;)
Generally speaking, use Rich Black for larger coverage areas (a black page for example) where you want the black to be deeper and fuller.
Never use Rich Black for smaller, more detailed print areas or text as the printer then has to trap 4 plates perfectly instead of just one as when you have 100% K that uses only that K plate.
Unless you pay for the spot colors, the printer is going to want you to print 4-color. This is nothing new and is not the sign of a 'bad' printer.
Find out if your printer is changing processes and make sure you talk to them at the BEGINNING of your jobs to give them the chance to help you in the most effective manner.
Hope that helps.
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"The price one pays for pursuing any profession or calling
is an intimate knowledge of its ugly side." - James Baldwin
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The Salon Design Tech
would be one of the instances where a printer could demand 100% K. Any body copy not solid K could be hell to hit on press. Though a printer might not REJECT artwork, they could ask you to be responsible if a job doesn't print, trap or separate correctly.
Photoshop sometimes tends to create oversaturated blacks. Black being a to rich, too much a composition of CMYK. This results in too much ink on a specific place and creating bad prints.
In a peticular picture you could use the replace volor adjustment
Also, you may not have your "ink limit" set correctly in Photoshop for offset printing. If the ink limit is too high, the paper will become saturated and wrinkle.
You should speak to your printer about what their requirements are and how to adjust them in Photoshop.
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Visit The Graphic Mac for graphics and Mac OS tips, reviews, tutorials and discussion.
Never heard of this setting?
Care to elaborate
Thanks
Trevor Smalldon
Graphic Artist
Basically Ink Limits is the amount of Ink of each color you put on the paper when printing. If your color is 100% Cyan, 100% Magenta, 100% Yellow and 100% Black - you have a 400% ink limit (sometimes called density).
MOST commercial printers like to have between 250-300% ink limit. That means that if you want a nice deep black, you can run something like 60% cyan, 60% magenta, 40% yellow and 100% black - which is a 260% ink limit (or density).
You access this information by going to Edit>Color Settings and in the Working spaces area, you click the CMYK drop down menu and select Custom CMYK. In this box you can see an area to enter in an ink limit and dot gain.
Optimal settings are usually in the range of this:
Ink Colors: SWOP (Coated)
Dot Gain: Standard 20%
Separation Type: GCR
Black Generation: Medium
Black Ink Limit 100%
Total Ink Limit 300%
UCA Amount: 0%
The Black Ink Limit tells photoshop that the darkest black can be up to 100%. If you change that to something like 80% you will find that when you select a color that is 100% black, when you convert the image to CMYK it will only be 80% black. Obviously, you don't want that to happen except in special circumstances, so leave it at 100%.
Do you see what I mean by this?
Now these settings occur when you convert an image from RGB to CMYK only. If the image is already CMYK, there's not a whole lot you can do to fix it.
Your best bet is to always use the "North America General Purpose 2" setting in the CMYK drop down menu of the Color Settings dialog box. This assures that "general" standars are used.
I could go into more detail on how to use these settings more, but for most people, the info I provided is enough. The only time I change the setting from North America General Purpose 2 is when I'm doing a full color newspaper ad. I have a custom setting where the ink limit is changed to around 225% - because newsprint absorbs the ink more.
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Visit The Graphic Mac for graphics and Mac OS tips, reviews, tutorials and discussion.
Thanks Jim, Awesome description, I appreciate the depth.
Trevor
Trevor Smalldon
Graphic Artist
Glad to shed some light
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Visit The Graphic Mac for graphics and Mac OS tips, reviews, tutorials and discussion.
Lets for a minute say you are sending a file to the printer and it contains 8 pt text in black: This should be done as 100% black and set to overprint (so it doesn't create a 'ghost effect' if and when it mis-registers) Ok now increase that text to 80 pt, what happens is at 100% black the ink coverage and the absorption rate of the paper causes the black to look 'grey'. So you make it 'Rich black' by adding other colors in the CMYK space (50% C 50% M 100% K) so that when they 'pull' off on the black the color still maintains a 'black' appearance, (albiet a little brown!)
Now if you do ALL your artwork in photoshop, it defaults to rich black for EVERYTHING (including your 8pt black text) Not good. You need to go into Photoshop into the color settings preferences and set the final output of the artwork (coated non coated) so that the artwork embeds the dot gain on the colors. That way you reduce the problems associated with over saturated colors including Black. Thats why its advisable to use a vector based program to do text most times that way you can control the text color and the over prints. Hope this was helpful?
"Try not, Do! or do not, there is no try."
-Yoda
K.I.S.S (Keep It Simple Stupid)
The only reason a printer would ask you to switch a 4-color black to a k-only black is out of two reasons.
1. They are using a digital printer which does not require a 4-color black to acheive the rich black effect.
2.Their prepress department are not competent.
B.T.W.
There are a lot of different rich black color settings, float around.
Our Company stays with a:
C: 40
M: 60
Y: 40
K:100
I hope this help. cheers my friends. =)
Hey -- who you calling stupid? ;-)
Not all presses are four-color so please add a third reason: they are printing the job on a one- or two-color (K plus a spot color) press and don't want the pre-press annoyance of creating a black plate (and, presumably another one for a spot color) from CMYK seps erroneously submitted by the client. The client pays for this extra effort, so it is a kindness if the printer clarifies this when they quote the job.
But I presume you've dropped in to promote your printing business, and if sharing your expertise helps you accomplish that, then good luck to you! :-)
Mara
Mara,
I was calling no one stupid. Its a acronym I like to use. (K.I.S.S)
Cheers =)
are you saying digital printers look the same at 0/0/0/100 as they do at 30/30/20/100 (or some other rich black combo)? every digital copier i've used (going back as far as the clc300 and today on nexpress/indigo/dc252) shows a difference using rich black vs pure black.
i don't know how else you can produce a rich black on a digital printer using only 100k.
A competent printer who sees a 1/2 point keyline in rich black will point out the problem before going to press and suggest new film be created to make sure the final piece is what the artist intended. The same for small type in rich black. The whole point of rich black is to either prevent show thru (the art or media under the black area showing thru) or to deepen the black to provide a darker experience or more contrast. Small type, thin lines, etc... should never be rich black because there is no reason for them to be rich black - they won't show thru and they're too thin to darken noticeably. So all you're doing is asking for registration problems and/or muddy-looking type.
Beyond that - there are hundreds of other reasons why you would want (or not want) rich black depending on the piece, the press, the printer, etc... This is not an issue that can be reduced down to a handful of reasons one way or the other. Rich black usage is essentially a part of trapping - something that cannot be picked up over night or in the space of one BBS thread on the internet.
As always - jmho.
For a printer Rich Black is the hardest to produce because you have to line up all four plates. 100%K makes their job much easier since only the K plate has to be used.
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The Salon Design Tech
Of course you can make the printer's job half as hard by using a 2-color rich black instead. The advantages being... easier to register, less ink coverage, a tinted color black (as opposed to a neutral tone) and the benefits of auto trapping 2 colors as opposed to black only.
I just wonder if there was a lot of fine print in rich black... we have to request clients who send "camera ready" work to us with fine print in rich black to change it (the print) to 100% k because otherwise, it would look like absolute crap after it's been through the press. Registration is definitely an issue, and with our product - newsprint - you really should avoid sending art with fine print in rich black. May be a different story with glossy magazine stock or something, but as a designer, I think I'd still avoid rich black with fine text.
That's my 2¢ on a 3-year-old question. :p
As already mentioned, rich 4C blacks serves it's purposes for variety of reasons. If a printer or separator informs you they can't handle 4C blacks, that ought to be your flag for not sending them your job. Surely, 4C black is difficult to trap correctly for a printer, but that is their job. Often, the difference between a good printer and lousy one, is simply their abilities (software/hardware/skills) in handle trapping...we have been working with a printer that can't even handle two-color trapping because they simply don't trap anything. Yet, they offer very competitive pricing for 2C jobs and hence we continue to use them, go figure.
Quick and dirty tutorial for rich black.
http://www.youtube.com/watch?v=0zhr-XiKhGs