Digital prepress question

[CatintheHat1]

I'm working on a new article, and hope I haven't asked these questions before, but I always need fresh views and up-to-date info.

1. If printing POD (digital press) and creating a PDF to go to the printer (say a book) the text should be 0/0/0/100. What can happen if it's not? Say it's rich black?

2. Can flipping from RGB to CMYK have an impact on the actual text or image quality beyond color? I was told it could make letters fuzzy, but I don't understand how.

[hewligan]

1) If you've got a rich black, then it's possible that the colours that make it up will not be correctly regsitered. For small objects like, say letters, this tends to show up pretty badly and will make the text look fuzzy. Exactly how bad this is depends on a bunch of factors, but digital POD isn't exactly known for quality.

2) The risk is that, since RGB -> CMYK and CMYK -> RGB aren't exact mappings, that K100 black of yours will get turned into a rich black. Then you get the same problem as in (1). You're also likely to see shifts in other colours. It's really not a good idea to shift between colour spaces any more than is necessary.

[SpugNothuson]

If there is time, get a sample of the digital print done by the printer you will be using. This will give you a good idea about how small type will behave itself. The differing qualities of digital print out there can be surprising.

Some digital printers will show you no furring around the edge of the type regardless of CMYK mix, some will even give furring on just K. You'll need to find out the exact nuances of the printer you will be sending your work to.

This is where it gets a little hazy for me. Never actually used a digital printer myself. If any of these details are incorrect I'm sure someone will say so.

The furring in digital print is caused by the Ink spreading on certain paper stocks, a large amount of Ink being applied to the area will cause more furring. This is not misregistered type, is that possible in digital print?

In Litho print, you will have 4 colours being placed on the sheet, CMYK, these can be misregistered, especially if the type is very small. Should be avoided if possible.

Pretty sure thats right. *crosses fingers*

[jimking]

It is the nature of a particular digi press. For example, take a rich black cover that was originally going to print offset, then it was now going to print on a iGen digital press instead. The rich black then should be changed to 100% black only, because on the iGen, built rich blacks for offset become muddy on this press. The 100% black prints very black, no need to build it. Same would pertain to built rgb or cmyk text. If one were to leave out the cmy and only print the black instead it may get that furry look because the black may not be 100%. It looks like 100% with all 4 colors but not the black by its self.

[CatintheHat1]

Again, I'm not looking for this info for a project, it's for an article and I can't just quote myself.

100% black over larger areas can be problematic, though, because it does not always spread evenly (the toner), so if it's part of a graphic or a background, rich black is the best choice to disguise any issues with uneven "inking" (a lot of our book covers go digital).

[doubting_thomas]

At our shop and on our "digital press" (Xerox 2060), I'd want your text 100% K
only, but black solids run much nicer if they're built 20, 20, 20, 100. The
2060 likes a built solid (even if the text ko's down to about 10pt excluding
script fonts). Solids that are built out of one of the CMYK colors tend to look
a bit uneven, depending on the actual size of the coverage.
RGB -> CMYK conversions of black work pretty poorly in general. Isolated heavy
builds of black tend to blast the image, or text, and create a light black halo around them.

[jimking]

Again, I'm not looking for this info for a project, it's for an article and I can't just quote myself.

100% black over larger areas can be problematic, though, because it does not always spread evenly (the toner), so if it's part of a graphic or a background, rich black is the best choice to disguise any issues with uneven "inking" (a lot of our book covers go digital).

I'm only speaking for the digital Xerox iGen only. Working in cmyk colorspace, we ran tests on the behest of the Xerox technicians. The rich blacks were muddy, the 100% blacks were very rich needing no build.

[CatintheHat1]

Just got off the phone with Xerox. They're claiming the iGens work better in RGB and there's a document here:
http://www.xerox.com/downloads/usa/en/p/Parsons_8_Edicts_Article.pdf

The HP machines promote CMYK.

Boy, this is fun.

[jimking]

Just got off the phone with Xerox. They're claiming the iGens work better in RGB and there's a document here:
http://www.xerox.com/downloads/usa/en/p/Parsons_8_Edicts_Article.pdf

The HP machines promote CMYK.

Boy, this is fun.

Watch out! :D If you were a offset printer looking to purchase an iGen to work hand in hand with your offset presses they would tell you the opposite. We needed jobs to go cross platform. We work the iGen in cmyk and build and match spot colors and do it all day long. We'll even rerun jobs that were printed offset originally on the iGen. We could not do this in RGB. But you can run jobs RGB.

[CatintheHat1]

I keep pushing my clients to run with CMYK for all the obvious reasons, but it doesn't help when companies do stuff like this, though. It's getting harder and harder to convince people the right way is still the right way.

[billyPGA]

I'm working on a new article, and hope I haven't asked these questions before, but I always need fresh views and up-to-date info.

1. If printing POD (digital press) and creating a PDF to go to the printer (say a book) the text should be 0/0/0/100. What can happen if it's not? Say it's rich black?

2. Can flipping from RGB to CMYK have an impact on the actual text or image quality beyond color? I was told it could make letters fuzzy, but I don't understand how.

Hi CatintheHat1,

There are RIPs that supports Black Texts in RGB that will Print 0/0/0/100K.
Even RGB grey can be printed with One Color using black. Look for a Printer that has an EFI RIP server with system 8.
As for the Images Color, It still depends on the Quality of the device Profile.

Cheers!:D
billyPGA

[steve2112]

A lot of digital press and copiers might be set to convert just rgb black to 100% black. Our fiery can be set to that so when you print RGB it takes all RGB and converts just that color black to 100% black.

steve