WetCanvas
Home Member Services Content Areas Tools Info Center WC Partners Shop Help
Channels:
Search for:
in:

Welcome to the WetCanvas forums. You are currently viewing our boards as a guest which gives you limited access to view most discussions, articles and access our other FREE features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please visit our help center.

Go Back   WetCanvas > Explore Subjects > Illustration
User Name
Password
Register Mark Forums Read

Salute to our Partners
WC! Sponsors

Our Sponsors
Closed Thread  
 
Thread Tools Display Modes
  #1   Report Bad Post  
Old 07-08-2016, 03:48 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Gamut color selection for P.O.D. book cover 240% ink limit

Although I'm not an illustrator, a quick search reveals that the topic of book covers arises in this forum from time to time. So I put this here, and will also leave a note in the color theory forum.

The attached zip file may be of interest to those of you who are designing a book cover, to be printed by one of those print-on-demand services that requires a 240% total ink coverage limit. This is quite popular in the USA. I have done it myself (only once!) with success, and wish to share.

The problem is that the gamut (available color range) is quite limited, with that printing process. Also, unless you have an expensive professional monitor, your own computer doesn't show all of the colors that you think it does. If you attempt to use too wide a range of colors, then the printed result will be quite a bit off (usually, too dull).

The problem is solved by soft-proof, in which your graphics program emulates the printer. Instead of designing something that the printer cannot handle, then having to keep re-editing your artwork, wouldn't it be nice to have advance knowledge of the available colors?

That's what the attachment does. It is a color chart showing which colors are expected to print the way you see them. Design using these colors to start, and the softproof (and print) will be close to expectations.

Of course, no warranty.

Note that this is NOT intended for poster design, or high-quality copies of artwork.
Attached Files
File Type: zip gamut240.zip (486.6 KB, 87 views)
  #2   Report Bad Post  
Old 07-10-2016, 06:12 PM
WFMartin's Avatar
WFMartin WFMartin is offline
A WC! Legend
Glendale, Arizona
 
Join Date: Sep 2002
Posts: 11,782
 
Hails from United States
Re: Gamut color selection for P.O.D. book cover 240% ink limit

I'm sure many artists don't understand the significance of the "240%" maximum ink limit.

I'm an ex-color separator for the litho trade, and I once worked closely with the pressroom to make their job easier.

Here's the explanation:

To reproduce a deep, solid black color, it would normally require 100% Cyan, 100% Magenta, 100% Yellow, and 100% Black.

That totals up to 400% of total layers of solid ink being laid upon the sheet of paper.

That also means that color complements are being used to create the "darks", and neutrals, without there being any consideration to total ink coverage. For example, the color Red, is grayed with Cyan, the color Green is grayed with Magenta, and the color Blue (Violet) is grayed with Yellow.

When colors are used as the "gray components" (complements) instead of Black to darken and gray colors, the image that appears on each of printed paper coming out of the press can vary in its color as ink densities fluctuate on the press. This color fluctuation does not occur if the color, Black, is used to gray, and darken colors instead of using the complementary colors to perform that function.

So, to compensate for this condition, we color separators used either UCR (Undercolor Removal), or GCR (Gray Component Removal) to "trade" the complement of each color for a more stable (and less expensive) Black ink.

When that operation occurs, instead of the 400% ink coverage, it is reduced to 240%, with Black taking on more of the duties of creating colors, rather than using the 3 complementary primary colors to serve as graying, and darkening colors.

In this case, for a deep, solid, Black-colored area, we would find that the halftone dot percentages would be as follows:

Cyan = 60%
Magenta = 40%
Yellow = 40%
Black = 100%

For a total of 240% total ink coverage on a solid Black area.

Usually, when accomplished properly, you could hold up 2 proofs (one with UCR, or GCR on it, and one without), and compare them side-by-side, and not see a difference.

The creation of this process is for the purpose of "helping" the pressroom during a run, and not to cause a visible "difference" in the color of the printed sheet.

However, an intelligent lithographer should have the "smarts" to be able to omit the UCR or GCR from their standard setup of the printing plates, if that's what you want. I worked for a printer who did that all the time. We printed 400% ink coverage almost all the time. When you have good pressmen, they can handle the inconvenience.
__________________
wfmartin. My Blog "Creative Realism"... http://www.wfmartin.com
  #3   Report Bad Post  
Old 07-10-2016, 09:45 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

Ah, so glad to see W.F. Martin comment here. I knew that he had a lot of printing press experience, and would be able to explain the significance of the ink limit better than I could.

Note that the print-on-demand (POD) service involves printing as low as one book at a time, from any number of different presses (and possibly different press technologies, even with one specific intent declared). The printer's workforce probably has not seen that book before, and may not see it again, and hardly cares. So, relying on pressman experience is not what's happening in POD. Instead, some low-level technician may or may not have the PDF checked by an automated program, and it may or may not go to a calibrated or compatible press. But in general the results are good, largely thanks to modern technology.

Last edited by Pinguino : 07-10-2016 at 09:48 PM.
  #4   Report Bad Post  
Old 07-15-2016, 12:15 AM
Ratchet Ratchet is offline
Veteran Member
 
Join Date: Jun 2016
Posts: 540
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

Am I understanding this correctly? This topic might be of interest to the computer graphic artist.

First, Thanks Mr. Martin for explaining this. There are pop up boxes in computer graphic programs that allow mixing colors on the screen or using pure black. The mix is percentages of pixels of each color in the color to be used. As I understand this, that is what the subject is, how to mix color by percentage.
There is a difference between ivory black and lamp black. I spent some time trying to mimic the exact shade of vine charcoal and the velvet black of lamp black. Interesting subject.

Not all of the colors that can be mixed can be printed. It is helpful to have information about what a colors a printer can render.

Last edited by Ratchet : 07-15-2016 at 12:19 AM.
  #5   Report Bad Post  
Old 07-15-2016, 12:18 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

I guess "computer graphic artist" would be a good description. But keep in mind that this is only useful if the end product is, as mentioned, something like a book cover printed with CMYK 240% ink limit (usually in the USA). If the graphic art is intended to be seen by users on computer screens, or printed using a more color-effective process (even your home inkjet is probably better than 240% ink limit), then the gamut image is not useful.

I picked the Illustration forum because a search revealed that the topic has been mentioned here before.

Incidentally, many "ordinary" photos fit within the process limit. But artists like to go for spectacular effects, which won't make it.

Those of you who do this, have a look at old book covers from the 1950s and 1960s, particularly paperbacks (such as "Pocket" brand). Many very famous books have appeared with rather plain covers: Catch-22, Animal Farm, To Kill a Mockingbird, etc. That's also true today. But it seems that in the P.O.D. market, authors figure that a random book will be improved by a shockingly-colored cover (so that in the end, all are equally shocking).
  #6   Report Bad Post  
Old 07-15-2016, 05:00 PM
Ratchet Ratchet is offline
Veteran Member
 
Join Date: Jun 2016
Posts: 540
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

It might be interesting to keep a palette within that range. I like the limited palette in old book covers. It could be very bold and striking.

Thanks for the information. It is of value to people beside book cover designers. And I learned something. That is always good.
  #7   Report Bad Post  
Old 07-16-2016, 12:15 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

Quote:
Originally Posted by Ratchet
It might be interesting to keep a palette within that range. I like the limited palette in old book covers. It could be very bold and striking.

Thanks for the information. It is of value to people beside book cover designers. And I learned something. That is always good.

I have taken up oil painting, and routinely browse through the relevant portions of this web site, to see what others have been doing. Generally, I prefer muted colors (except where "necessary").

Sometimes I inspect the gamut of artwork photos posted to the forums, using software on my color-calibrated computer. Since I have a cheap lapop (probably typical of most users here), it has limited gamut. But with the main exception of sunset scenes, just about all of the posted images have almost all of their colors fitting within the gamut limits I described above. That's because, other than straight-from-tube cadmiums and a few others, all commonly-used artist paints and mixtures produce colors within the capability of monitors and commercial (not art-quality) printers. In the case of out-of-gamut colors, it doesn't take much adjustment to produce in-gamut colors that are not obviously different. This is in the nature of painted art, which necessarily has a limited range compared to real life.
  #8   Report Bad Post  
Old 07-17-2016, 08:33 PM
WFMartin's Avatar
WFMartin WFMartin is offline
A WC! Legend
Glendale, Arizona
 
Join Date: Sep 2002
Posts: 11,782
 
Hails from United States
Re: Gamut color selection for P.O.D. book cover 240% ink limit

I guess I'm not sure just what your goal is, here.

Computer screen monitors ALWAYS have a greater gamut of colors than any medium that is composed of pigments. The Red, Green, Blue light on a monitor screen combine to create Cyans, and Magentas that are much purer than anything we can create with paints. That is because colors composed of RGB light on a computer monitor have much greater gamut than anything we can achieve with paint, ink, or dye.

Yellow pigment is pretty close to matching colors of light, but Cyan, and Magenta fall quite a bit short in terms of pigment colors.

However, I'm not quite sure of your goal. So far, you have made a few statements, but I'm not sure toward what end.

In terms of the POD printing, there should be no reason that a competent (notice I said "competent") printer couldn't furnish you with a 400% ink coverage, rather than the "usual" profile of the 240% to which you alluded. Believe me when I state that it can be done, and with the press of a button.
__________________
wfmartin. My Blog "Creative Realism"... http://www.wfmartin.com

Last edited by WFMartin : 07-17-2016 at 08:42 PM.
  #9   Report Bad Post  
Old 07-19-2016, 12:12 PM
Ratchet Ratchet is offline
Veteran Member
 
Join Date: Jun 2016
Posts: 540
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

The goal is to understand more about how different technologies, including oil paint, printers and computers render color.

Computers can render purer colors than any other medium but those colors are not necessarily "good colors." There is a curious flatness to computer rendered images as "pure color" is not natural and difficult to mix out when painting on the screen.

The printer colors are not natural either. On paper, there is a big difference between vine charcoal and lamp black. Mixing either of those is a task on a computer and then there is the printer. Any computer graphic person who has tried to mimic the texture and shade of aged manuscripts can attest to the difficulty of manually mixing colors in any medium, and especially on a computer.

Last edited by Ratchet : 07-19-2016 at 12:58 PM.
  #10   Report Bad Post  
Old 07-19-2016, 12:12 PM
Ratchet Ratchet is offline
Veteran Member
 
Join Date: Jun 2016
Posts: 540
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

X

Last edited by Ratchet : 07-19-2016 at 12:54 PM. Reason: Double Post
  #11   Report Bad Post  
Old 07-20-2016, 02:23 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

WFM: The "competent" printer is not what is under discussion here. Rather, it is "lowest common denominator." In those few cases where P.O.D. book will turn out to sell very well, the printing service will change technologies to accommodate volume.

Actually, 240% ink limit is not "usual" for the press technology. I have been informed (anonymously) that the usual ink limit is 300%, but the automated presses are staffed by lowly workers who don't really do much except move things from place to place. And, the job-shopper might use a service that otherwise spends most of its time with newsprint, which does have a 240% ink limit. Since the press run is sporadic, and almost always very small in total, there is no reason to invest effort. In fact, the concept of P.O.D. is that all of the work is done by the author, who submits press-ready standard files, or hires someone to do it. From there, it's the publishing equivalent of burger-flipping at Mickey D's.

Furthermore, the actual printing device is often a high-end inkjet, by "high end" I mean for automated volume and paper handling, rather than art. Its technology is unlike the modified-SWOP printer profile intent. So, the entire color-managed workflow is rather phony. But those are the rules. Submit a PDF that doesn't comply (as checked by software, not humans) and it may be rejected.

You have to ask yourself whether the typical P.O.D. book, which may be a memoir that hardly anyone cares about, or an obscure diet and health book, or psychological self-help, or yet another sword-sorcery epic, would ever need a 400% ink cover.

When I submitted the PDF/x-1a of the book block (typeset using LaTeX), someone causally asked me what "Garamond" was. She had never seen a book block that wasn't set with Times New Roman or similar, because all others she had seen were exported from MS Word, not typeset with a book typeface. Did you ever think that someone in the printing business would not know what "Garamond" was? Probably a college intern.

Still, I cannot complain about the finished product. Actually exceeded my expectations.
  #12   Report Bad Post  
Old 09-29-2016, 05:58 AM
inkslinger69's Avatar
inkslinger69 inkslinger69 is offline
Veteran Member
Hendersonville, NC
 
Join Date: Apr 2012
Posts: 696
 
Hails from United States
Re: Gamut color selection for P.O.D. book cover 240% ink limit

very interesting..... out of my league, but interesting!
  #13   Report Bad Post  
Old 07-27-2017, 05:35 PM
Pinguino's Avatar
Pinguino Pinguino is offline
Lord of the Arts
Monterey Bay area, California
 
Join Date: Dec 2015
Posts: 2,126
 
Re: Gamut color selection for P.O.D. book cover 240% ink limit

Further note: I am informed that the reason for the 240% ink limit, specifically for printed book covers using P.O.D. technology, is that the final laminate may detach if there is too much ink. Tiny spots over 240% rarely matter.

Those who paint in oils, and worry about delamination, will understand.
  #14   Report Bad Post  
Old 07-31-2017, 08:25 PM
ptrkgmc's Avatar
ptrkgmc ptrkgmc is offline
Veteran Member
Calabasas, CA
 
Join Date: May 2017
Posts: 817
 
Hails from United States
Re: Gamut color selection for P.O.D. book cover 240% ink limit

Photoshop will easily tell you if color work is out of gamut. It will also allow you to adjust a piece of work to bring it into gamut.
I don't know if Gimp will do this, I would hope, ...
It is true that in gamut works tend to be dull, but this is not a bad thing, the illustrator just need to limit his palate.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 02:41 PM.


© 2014 F+W All rights reserved.