Hi I will leave the "Answer" to otherthoughts" - second part of the question, in is reply to me -- to some one else!!!!! and pose one myself -- a " Simple One " --- What is Surface Tension ???
Regards, Alois
Last edited by Alois Senefelder; 01-24-2009 at 05:22 PM.
Reason: ******** !!!!!!!!!!!!!
Perhaps what I really meant to ask is why equal amounts of the subtractive primary colors CMY, result in a "Muddy Brown" color instead of a neutral gray?
Because CMY inks are not perfect filters of light.
On a side-bar, some have argued, me included, that equal values of CMY - a.k.a. "brown balance" would be a better metric than gray balance on press.
With Cyan being the least efficient filter, hence the 60% dot over the 50% for Magenta and Yellow.
Even though everyone working with color knows that 60/50/50 makes gray. I only had one student in all the scanner training classes I gave answer this question for me. Gordo makes two.
I think otherthoughts gets my thinking. With all of the technology available, a relatively inexperienced operator could give you very good results. However a pressman with years of experience wil give you that extra 10-15% of quality.
I recall showing one of our very lower end operators (5 years exp. and struggling with 1 col black on GTO) the press. I explained to him about ink presetting and suchlike and the response I got was , 'Well anybody could run this!'.
The thing is he probably would have faired better on a 5 col 74 than on a 1 col GTO!
I think academic background is very important once you know the basic ..you can run any machine,But you can not feel colors with academic background so you need both tools and training for your eyes .About working with old technology makes it easy to work with advanced one i agree with that but you still need to learn how to use measuring tools and to give your eyes a chance to have the color feeling......
With Cyan being the least efficient filter, hence the 60% dot over the 50% for Magenta and Yellow. Even though everyone working with color knows that 60/50/50 makes gray. I only had one student in all the scanner training classes I gave answer this question for me. Gordo makes two.
Best Regards otherthoughts
I think you misunderstood what I wrote. I did not say that equal % of CMY makes gray. I wrote that equal parts of CMY makes "brown" and that "brown balance," rather than gray balance, has been argued by some (including me) as potentially a better metric on press than gray balance.
My humble apologies to Alois and Gordo for being less than clear when stating the questions and replies as well.
Gordo, I was attempting to further refine your initial statement "Because CMY inks are not perfect filters of light" in an effort show the relationship between my original question and my second. I was not addressing the "brown balance" statement. Sorry for not making myself clear.
It looks like I fouled things up more than I helped here. Sorry.
To explain, hopefully with some greater clarity what my intention was and why.
I am the kind of guy that always wants to know why something is the way it is. Especially when I am getting paid for it and shoulder some responsibility for it's outcome.
I firmly believe that the best people in any field take the time to understand how the entire system works and how one part interacts with another. I personally was never content to simply push the button just because everyone said "that's how it's done", I always asked "Why?", Needless to say, I was a pain in the neck to a great many people.
When exceptional people crossed my path, I pestered them with an endless stream of "whys" and soaked up as much knowledge as they were willing to share with me, either that or I had exhausted their patience with me.
As an example, I had been running a 4-color Heidelberg GTO for quite some time in the late 80's and always fighting with fitting the plates. If I were to fit the register marks, typically the images were out, both circumferentially and side to side. Nearly every job was a struggle to find some happy medium. Then one day, after we had hired a new stripper, all of a sudden everything began fit marvelously. Day after day, week after week.
I knew right then and there that the new stripper was someone I needed to talk to and could learn from. I was about 25 yrs old then and of course the new stripper was an older guy approaching 50 years old and had done every type of job you could name from one end of the production gamut to the other, including all the changes that had occurred with time and progress along the way.
This exceptional fellow could do things that boggled my mind. He was equally comfortable in the pressroom and prepress. It was with his help that I made the leap from lead pressman running a Heidelberg MOFPH, to the stripping department and later to become a scanner operator. The grass seemed greener to me in prepress, and in many ways it was.
When I applied for and got hired on with Linotype-Hell as a scanner trainer, they called my employer for a reference. They asked one of the owners "what I knew", he replied to them "I don't know what he knows, but he was the only one that could make things work". In many ways I give credit for that owner's reference to that exceptional fellow who had helped me so much.
I realize that I have strayed a bit here, but I felt it was in keeping with the original question posed by the thread originator, regarding old school and new school.
To get to the chase here. When I was an instructor, I tried to always explain to my students how the button works and why it works along with any caveats. I didn't just want them to become familiar with the buttons on the scanner. I wanted them to better understand the entire system so that they would know both when, as well as, when not to push the button.
One of the questions I asked at some point in every class was, "why does the Cyan require 10% more ink than the Magenta or Yellow to make a gray?". To explain the question further I would add "in the subtractive color space, cyan filters red light, magenta filters green light and yellow filters blue light right? Everyone would agree, so then I would say "why does the cyan ink require so much more to do what the magenta and yellow do with less?", "what's wrong with the cyan ink".
Now mind you some of my student's had been working with color for many years and may have worked for some of the best companies you might care to mention. Only one student of perhaps a few hundred students I worked with answered the question without delay and accurately, "the cyan ink is a less efficient filter of light than the magenta or yellow". That student and I became friends and still are to this day.
To sum up. Without exception, every single student could tell me the numbers that produced gray in their shops, 60/50/50, 60/50/47, 60/49/44 etc. etc. I just wanted them to know the reason why that was. I tried to pass on to them all the favors that a great many people had given me. It seems to me that the world is a nicer and less stressful place when we do our best to help the man who wants to be helped.
I personally learned about ink efficiency and lots more at a GATF class when I was a pressman. I always measured the ink efficiency, trapping, etc of the press samples any ink salesman brought me with a densitometer right in front of him and compared it to the inks I was currently running. I guess I pissed off my fair share of ink salesmen.
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Originally Posted by otherthoughts
Thanks!
